1. Introduction1.導(dǎo)言
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Most agricultural crops require pollination (through insects or wind) for successful production. Weather events or asynchrony in flowering between a crop and its polliniser can cause pollination failure, and insect-pollinated crops are additionally vulnerable to declines in insect pollination services. The majority of insect pollination to crops is provided by managed Western honey bees (Apis mellifera) and, for some crops, the regional demand for pollination services can be extreme during bloom, requiring bees to be transported over large distances to service the crop. Globally, pollinator-dependent crops represent an increasing proportion of total agricultural area [1,2], increasing demand on the supply of honey bees and pollination services. While the number of honey bee colonies has increased across the globe in response, the growth rate has not kept pace with demand [3], leading to pollination deficits [4] and increased prices for pollination services. In addition, a number of intersecting issues threaten hive supply during the pollination window, including: increasingly frequent and severe weather events (such as fires, floods, and cyclones) destroying hives as well as resources in the landscape necessary to sustain them [5]; restrictions limiting transport of hives between regions [6,7]; reduction in colony resilience due to pesticide exposure [8]; and competition for hives among crop producers [9]. Sustainable production of high-value crops may require new approaches to pollination services that supplement or substitute honey bees if, or when, there are not enough colonies available to meet demand.
▲kiwipollen
大多數(shù)農(nóng)作物需要授粉（通過(guò)昆蟲或風(fēng)）才能成功生產(chǎn)。天氣事件或作物與其傳粉者開花不同步會(huì)導(dǎo)致授粉失敗，昆蟲授粉的作物也容易受到昆蟲授粉服務(wù)下降的影響。作物的大部分昆蟲授粉是由有管理的西方蜜蜂（Apis mellifera）提供的，對(duì)于某些作物，在開花期間，該地區(qū)對(duì)授粉服務(wù)的需求可能非常大，需要將蜜蜂長(zhǎng)途運(yùn)輸來(lái)為作物服務(wù)。在全球范圍內(nèi)，依賴傳粉媒介的作物在農(nóng)業(yè)總面積中所占的比例越來(lái)越大[1,2]，對(duì)蜜蜂供應(yīng)和授粉服務(wù)的需求也在增加。盡管全球蜜蜂群體的數(shù)量有所增加，但增長(zhǎng)速度并沒(méi)有跟上需求的步伐，導(dǎo)致授粉不足和授粉服務(wù)價(jià)格上漲。此外，在授粉窗口期間，許多交叉問(wèn)題威脅著蜂箱的供應(yīng)，包括：日益頻繁和嚴(yán)重的天氣事件（如火災(zāi)、洪水和颶風(fēng)）破壞了蜂箱以及維持蜂箱所需的景觀資源；限制蜂箱在地區(qū)之間運(yùn)輸?shù)南拗?；農(nóng)藥暴露導(dǎo)致菌落彈性降低；以及作物生產(chǎn)者之間對(duì)蜂箱的競(jìng)爭(zhēng)。如果沒(méi)有足夠的蜂群來(lái)滿足需求，高價(jià)值作物的可持續(xù)生產(chǎn)可能需要新的授粉服務(wù)方法來(lái)補(bǔ)充或替代蜜蜂。
▲Bee pollination
Humans have tried to replace natural pollinators before, with varying degrees of success. Date palms have successfully been hand-pollinated by humans for over 4000 years—documented since at least the Code of Hammurabi [10]. Other plants have been more challenging, as most have smaller flowers, produce less pollen, and have a shorter working life for each pollen grain. Pollen from many plant species has been successfully collected and stored for breeding new varieties, but this requires a tiny fraction of the amount of pollen required to fully replace, or even supplement, insect pollinators [11]. Beyond date palm, the economics of only a handful of other crops, most notably vanilla, can support the labour-intensive cost of pollination by hand. Even in cases where manual pollination has been successful—such as the human pollinators of Maoxian County in China, where a massive force of labourers hand-pollinated vast tracts of apples with paintbrushes in 2001 [12]—they are not always sustainable. Researchers visiting Maoxian Country 10 years later found most of the apple trees had been cut down and replaced by wind-pollinated walnut and self-fertile loquat; both can be pollinated with few, or no, insects [12]. Manual pollination in Maoxian County arose because the high use of pesticides created an environment where beekeepers refused to risk their hives. It was abandoned due to labour migration into the cities.
人類以前曾試圖取代自然傳粉者，取得了不同程度的成功。椰棗樹已經(jīng)成功地由人類人工授粉了4000多年，這至少可以追溯到《漢謨拉比法典》。其他植物則更具挑戰(zhàn)性，因?yàn)榇蠖鄶?shù)植物的花朵較小，產(chǎn)生的花粉較少，每個(gè)花粉粒的工作壽命也較短。許多植物物種的花粉已被成功收集和儲(chǔ)存，用于培育新品種，但這只需要完全替代甚至補(bǔ)充昆蟲傳粉者所需花粉量的一小部分。除了椰棗，只有少數(shù)其他作物的經(jīng)濟(jì)效益，尤其是香草，可以支持人工授粉的勞動(dòng)密集型成本。即使在人工授粉成功的情況下——比如中國(guó)茂縣的人類授粉者，2001年，大量工人用畫筆為大片蘋果人工授粉——它們也并不總是可持續(xù)的。10年后，訪問(wèn)茂縣的研究人員發(fā)現(xiàn)，大多數(shù)蘋果樹已被砍伐，取而代之的是風(fēng)媒授粉的核桃和自育枇杷；兩者都可以用很少或沒(méi)有昆蟲授粉[12]。茂縣的人工授粉之所以興起，是因?yàn)榇罅渴褂脷⑾x劑創(chuàng)造了一個(gè)養(yǎng)蜂人拒絕冒蜂箱風(fēng)險(xiǎn)的環(huán)境。由于勞動(dòng)力向城市遷移，它被廢棄了。
For several decades, a handful of industries—primarily stonefruit, pipfruit, and kiwifruit—successfully collected and applied pollen using a wide array of pollination technologies, from hand applicators through to tractor-mounted spray systems. Kiwifruit is a flagship crop for artificial pollination, where its dioecious nature (male and female flowers on separate plants), lack of nectar, and high potential for fruit set led to early exploration of artificial pollination [13]. This research demonstrated that supplementing insect pollinators with artificial pollination increased both fruit set and fruit quality [14,15]. The success of early trials in New Zealand led to the development of an array of pollen delivery devices that reduced labour and made artificial pollination an important tool for many growers, and it has become the primary strategy used in Italy [16], southern China [17,18], and Korea [19]. Elsewhere, it is used as a supplemental pollination strategy, with approximately half the kiwifruit growers in New Zealand using supplemental artificial pollination. Several New Zealand companies commercially harvest and mill kiwifruit pollen, supplying it to domestic and global growers [20,21]. Tools developed for kiwifruit have been adapted for, and employed in, other cropping systems [22,23,24].
▲Kiwi insect pollination
Most artificial pollination technologies require a high-quality source of pollen to be successful—a chicken-and-egg situation for crop producers in places that lack existing pollen harvesting and supply infrastructure, although a number of small-scale pollen collection methodologies exist. Despite these limitations, the last decade has seen many researchers, as well as small and start-up companies, take on the pollination challenge, evidenced by the increasing numbers of patents published regarding artificial pollination devices (Figure 1 and Figure 2; Appendix A).
大多數(shù)人工授粉技術(shù)需要高質(zhì)量的花粉來(lái)源才能成功，這對(duì)缺乏現(xiàn)有花粉采集和供應(yīng)基礎(chǔ)設(shè)施的地方的作物生產(chǎn)者來(lái)說(shuō)是一種雞和蛋的局面，盡管存在一些小規(guī)模的花粉采集方法。盡管存在這些局限性，但在過(guò)去的十年里，許多研究人員以及小型和初創(chuàng)公司都面臨著授粉挑戰(zhàn)，這可以從越來(lái)越多的人工授粉設(shè)備專利中得到證明（圖1和圖2；附錄A）。
▲Kiwi insect pollination
2.花粉采集
The quantity of pollen required for artificial pollination depends on both the crop species and the device used to deliver it. Some crops, such as date palm and anemophilous (wind-pollinated) trees, produce large quantities of pollen that is relatively easy to collect. However, most crops, including almond, apple, and kiwifruit, produce a relatively small number of pollen grains per flower and require more labour [29]. This suggests two goals for practical artificial pollination: securing a supply of inexpensive, high-quality pollen, and ensuring that as little pollen as possible is wasted during application.
人工授粉所需的花粉量取決于作物種類和用于輸送花粉的設(shè)備。一些作物，如椰棗和風(fēng)媒（風(fēng)媒授粉）樹，會(huì)產(chǎn)生大量相對(duì)容易收集的花粉。然而，大多數(shù)作物，包括杏仁、蘋果和獼猴桃，每朵花產(chǎn)生的花粉粒數(shù)量相對(duì)較少，需要更多的勞動(dòng)力[29]。這為實(shí)用的人工授粉提出了兩個(gè)目標(biāo)：確保廉價(jià)、高質(zhì)量的花粉供應(yīng)，并確保在應(yīng)用過(guò)程中浪費(fèi)盡可能少的花粉。
▲Bees pollinate kiwifruit
Pollen is typically most viable at the time of anthesis [30], just as the anthers begin to release pollen. However, collecting flowers at this stage can result in significant pollen losses, as flowers can release the majority of their pollen on the day of anthesis [15,28]. To obtain the highest quantity of pollen per flower, it is generally preferable to harvest immediately prior to anthesis to prevent pollen losses [30].
花粉通常在開花時(shí)最具活力[30]，就像花藥開始釋放花粉一樣。然而，在這個(gè)階段收集花朵可能會(huì)導(dǎo)致花粉大量流失，因?yàn)榛ǘ淇梢栽陂_花當(dāng)天釋放大部分花粉[15,28]。為了獲得每朵花的最高花粉量，通常最好在開花前立即收獲，以防止花粉損失[30]。
▲Bees pollinate kiwifruit
Three approaches have been taken to collecting pollen: hand-picking or mechanically harvesting flowers just prior to anthesis and extracting the pollen; vacuuming pollen directly from flowers; and using pollen traps attached to honey bee hive entrances to obtain bee-collected pollen from the crop (Figure 3).
收集花粉有三種方法：在開花前手工采摘或機(jī)械收割花朵并提取花粉；直接從花中吸出花粉；并使用附著在蜜蜂蜂箱入口的花粉陷阱從作物中獲取蜜蜂采集的花粉（圖3）。
Hand-picking individual flowers, inflorescences, or panicles has been successful in plants that produce copious quantities of pollen. For date palm, entire panicles are harvested, dried, and then filtered [28]. The tassels, strobili, or catkins (male reproductive structures) of wind-pollinated plants can be handled similarly [24,31,32,33,34,35].
在產(chǎn)生大量花粉的植物中，手工采摘單個(gè)花朵、花序或圓錐花序是成功的。對(duì)于椰棗，整個(gè)穗被收獲、干燥，然后過(guò)濾[28]。風(fēng)媒傳粉植物的流蘇、球果或柳絮（雄性生殖結(jié)構(gòu)）可以類似地處理[24,31,32,33,34,35]。
▲Bees pollinate kiwifruit
Entomophilous plants (pollinated by insects) typically produce less pollen, making collection more challenging. Anthers can be manually excised from individual flowers—an approach employed in artificial pollination research [36,37], but the method is labour-intensive and is economical only for small-scale application (e.g., breeding programmes, vanilla and cacao pollination). Larger-scale pollination was enabled by methods of mechanically separating pollen from whole flowers for kiwifruit [15,23,38,39], cherimoya [30], date palm [22,28], and almond [40]. This typically involves drying the collected flowers, milling the flowers to separate the anthers from other floral structures, allowing the anthers to dehisce under controlled conditions, and using a filter- or cyclone-type cleaning machine that extracts the anthers and pollen, which can then be dried. The pollen is then extracted using a sieve attached to a vacuum. Anther-drying has been identified as a rate-limiting step in the pollen-milling process outlined above, but attempts to reduce drying time by increasing temperature or air-flow negatively affect viability beyond a certain point [15].
昆蟲學(xué)植物（由昆蟲授粉）通常產(chǎn)生的花粉較少，這使得采集更具挑戰(zhàn)性?；ㄋ幙梢詮膯味浠ㄉ先斯で谐@是人工授粉研究中采用的一種方法[36,37]，但這種方法勞動(dòng)密集，僅適用于小規(guī)模應(yīng)用（如育種計(jì)劃、香草和可可授粉）。通過(guò)機(jī)械分離獼猴桃[15,23,38,39]、番荔枝[30]、椰棗[22,28]和杏仁[40]全花花粉的方法，實(shí)現(xiàn)了更大規(guī)模的授粉。這通常涉及干燥收集的花朵，研磨花朵以將花藥與其他花結(jié)構(gòu)分離，使花藥在受控條件下開裂，并使用過(guò)濾器或旋風(fēng)式清潔機(jī)提取花藥和花粉，然后可以干燥。然后用真空篩提取花粉?；ㄋ幐稍镆驯淮_定為上述花粉碾磨過(guò)程中的限速步驟，但試圖通過(guò)提高溫度或空氣流量來(lái)減少干燥時(shí)間，會(huì)對(duì)超過(guò)某一點(diǎn)的存活率產(chǎn)生負(fù)面影響[15]。
▲播宏果業(yè)獼猴桃花粉旋風(fēng)分離采集花粉工序照片
Flowers are commonly sourced from growers (either to apply back to the same orchard, or sold for pollen processing), and increasingly, from orchards grown specifically to supply pollen. There are, however, several challenges with orchards dedicated to pollen production, including lower financial return than fruiting orchards and a very brief, high-labour demand for harvesting flowers. As a result, a combination of dedicated pollen production and fruiting orchards is likely to remain in use [41,42,43]. Anecdotally, harvest rates for manual picking vary wildly with the experience of pickers and orchard management practices. A mixed-sex kiwifruit orchard (not dedicated to pollen production), for example, could yield between 20 and 200 kg-flower/ha, with a typical yield of 30–40 kg-flower/ha from a well-trained team in a well-managed orchard. Picking rates vary from less than 1 kg-flower/day up to 40 kg-flower/day, although again this is heavily dependent on experience and orchard practice. Pollen yield for good male cultivars reportedly varies from 8.5 g/kg-flower up to 10.5 g/kg-flower with careful attention to the process. Poor-producing cultivars may yield only 4 g/kg-flower (pers. comm. Mat Johnston).
花卉通常來(lái)自種植者（要么用于回用同一果園，要么用于花粉加工），而且越來(lái)越多地來(lái)自專門為供應(yīng)花粉而種植的果園。然而，專門用于花粉生產(chǎn)的果園存在一些挑戰(zhàn)，包括比果園更低的經(jīng)濟(jì)回報(bào)，以及收獲花朵的勞動(dòng)力需求非常短暫和高。因此，專門的花粉生產(chǎn)和果園很可能會(huì)繼續(xù)使用[41,42,43]。據(jù)傳，人工采摘的收獲率因采摘者的經(jīng)驗(yàn)和果園管理實(shí)踐而異。例如，一個(gè)混合性別的獼猴桃園（不專門用于花粉生產(chǎn)）每公頃可以生產(chǎn)20到200公斤的花，在管理良好的果園里，訓(xùn)練有素的團(tuán)隊(duì)每公頃的典型產(chǎn)量為30到40公斤的花。采摘率從每天不到1公斤花到每天40公斤花不等，盡管這在很大程度上取決于經(jīng)驗(yàn)和果園實(shí)踐。據(jù)報(bào)道，良好雄性品種的花粉產(chǎn)量從8.5克/千克花到10.5克/千克花不等，要仔細(xì)注意這一過(guò)程。產(chǎn)量低的品種可能只生產(chǎn)4克/公斤的花（通訊員馬特·約翰斯頓）。
▲Kiwi insect pollination
Recently, a mechanical pollen harvesting device has been developed for almond, which uses a tree shaker to dislodge flowers at full bloom, collecting them on a tarp beneath the tree [40,42]. Flowers are dislodged at various states of maturity, so pollen recovery rates are lower on a per-flower basis, but bulk harvesting significantly reduces the cost of collection. Harvesting machinery has also been developed for maize flowers, removing tassels for later milling and application in the production of hybrid maize seed [35]. More than 80 L of pollen can be collected each day with this machinery, a high yield made possible by the fact that maize is wind-pollinated and therefore produces large quantities of pollen [35].
最近，一種用于杏仁的機(jī)械花粉采集裝置已經(jīng)開發(fā)出來(lái)，該裝置使用樹木搖床在盛開時(shí)移走花朵，將它們收集在樹下的防水布上[40,42]?；ǘ湓诟鞣N成熟狀態(tài)下都會(huì)脫落，因此每朵花的花粉回收率較低，但批量收獲顯著降低了采集成本。還開發(fā)了玉米花收割機(jī)械，去除穗以備后續(xù)碾磨，并應(yīng)用于雜交玉米種子的生產(chǎn)[35]。使用這種機(jī)器每天可以收集超過(guò)80升的花粉，玉米是風(fēng)媒傳粉的，因此可以產(chǎn)生大量花粉，從而實(shí)現(xiàn)高產(chǎn)[35]。
Mechanical harvesting techniques are relatively new, so the primary driver of pollen cost is labour. In November 2022, during the pollination season, the price was NZD 8250/kg (USD 5200/kg) for kiwifruit pollen in New Zealand, and USD 7500–8500/kg for pipfruit and stonefruit pollen from the USA [44]. In contrast, date pollen is available at USD 150–225/kg in the USA and Mexico [28].
機(jī)械收割技術(shù)相對(duì)較新，因此花粉成本的主要驅(qū)動(dòng)力是勞動(dòng)力。2022年11月，在授粉季節(jié)，新西蘭的獼猴桃花粉價(jià)格為8250新西蘭元/公斤（5200美元/公斤），美國(guó)的梨果和石果花粉價(jià)格為7500-8500美元/公斤[44]。相比之下，在美國(guó)和墨西哥，棗花粉的價(jià)格為150-225美元/公斤[28]。
In the pursuit of less-expensive material for artificial pollination, there has been considerable interest in pollen collected by honey bees, despite its variable viability and purity. The impurities stem from two sources: honey bees mix pollen with nectar to form pollen pellets on their legs, and additionally may not be foraging exclusively on the target crop. Trials have successfully demonstrated fruit set using bee-collected pollen in kiwifruit [45,46,47], peach [48], apple [48,49], pear [48,50], almond [51,52], and canola [53]. Researchers found, however, that fruit drop was higher and fruit weight lower in flowers fertilised with bee-collected pollen instead of pure pollen. Consequently, higher application rates are required. Several studies have noted lower fruit set from bee-collected pollen, which was improved by washing it and formulating it to remove excess sugars, which otherwise appear to inhibit pollen germination [30,49,53]. A recent study found that pollen on bees’ bodies is much more able to achieve fruit set than that stored on their corbiculae; bees that do not pack their pollen with sugars (e.g.,?Megachile rotundata, Megachilidae;?Halictus?spp., Halictidae) do not show the same detrimental effect on pollination potential [53], but it has not yet been possible to collect pollen from these species at sufficient scale. More research into the handling and processing of bee-collected pollen is needed before it can be used for large-scale pollination.
為了尋找更便宜的人工授粉材料，人們對(duì)蜜蜂收集的花粉產(chǎn)生了相當(dāng)大的興趣，盡管其存活率和純度各不相同。這些雜質(zhì)來(lái)自兩個(gè)來(lái)源：蜜蜂將花粉與花蜜混合，在腿上形成花粉粒，而且可能不會(huì)只在目標(biāo)作物上覓食。試驗(yàn)已成功證明使用蜜蜂采集的花粉在獼猴桃[45,46,47]、桃[48]、蘋果[48,49]、梨[48,50]、杏仁[51,52]和油菜[53]中坐果。然而，研究人員發(fā)現(xiàn)，用蜜蜂采集的花粉而不是純花粉受精的花朵，落果率更高，果實(shí)重量更低。因此，需要更高的申請(qǐng)率。幾項(xiàng)研究發(fā)現(xiàn)，蜜蜂采集的花粉坐果率較低，通過(guò)清洗和配制花粉以去除多余的糖來(lái)改善坐果率，否則這些糖似乎會(huì)抑制花粉萌發(fā)[30,49,53]。最近的一項(xiàng)研究發(fā)現(xiàn)，蜜蜂身上的花粉比儲(chǔ)存在球莖上的花粉更容易坐果；不將花粉包裹在糖中的蜜蜂（例如，圓斑大蜂、圓斑大蚊科、Halictus spp.、Halictidae）對(duì)授粉潛力沒(méi)有同樣的不利影響[53]，但還不可能以足夠的規(guī)模從這些物種中收集花粉。在將蜜蜂采集的花粉用于大規(guī)模授粉之前，需要對(duì)其處理和加工進(jìn)行更多的研究。
Pollen can also be vacuumed directly from some flowers, catkins, or strobili. The viability of pollen collected in this way is generally much higher than that with other methodologies [30,38]. Furthermore, in some designs, the vacuum may be reversed to apply collected pollen immediately without further processing or storage. Vacuum collection has successfully been employed to collect quantities of larch [54], Douglas fir [55], olive (manual [23], mechanised [30]), kiwifruit [23,38,56], and cannabis [57] pollen. Pollen yield varies with plant species, with yields 500 cc/h being reported for Douglas fir [55], 140 g/h being reported in kiwifruit [38] and 100–200 g/h in olive (cultivar-dependent [23]). A handful of prototype mechanical pollen-harvesting systems have been developed to vacuum pollen from trees. These rely on surrounding the tree with a vacuum and filtration system, while using a tree shaker to release the pollen (olive [30], larch [54]). These mechanised systems can harvest up to ten times the quantity of pollen as handheld vacuum devices can, although the pollen tends to be of somewhat lower quality [54].
花粉也可以直接從一些花、柳絮或球果中抽出。以這種方式收集的花粉的存活率通常遠(yuǎn)高于其他方法[30,38]。此外，在某些設(shè)計(jì)中，可以顛倒真空狀態(tài)，立即施加收集到的花粉，而無(wú)需進(jìn)一步加工或儲(chǔ)存。真空收集已成功用于收集大量落葉松[54]、花旗松[55]、橄欖（手動(dòng)[23]、機(jī)械化[30]）、獼猴桃[23,38,56]和大麻[57]花粉?；ǚ郛a(chǎn)量因植物種類而異，道格拉斯冷杉的產(chǎn)量為500毫升/小時(shí)[55]，獼猴桃的產(chǎn)量為140克/小時(shí)[38]，橄欖的產(chǎn)量為100-200克/小時(shí)（取決于品種[23]）。已經(jīng)開發(fā)了一些原型機(jī)械花粉采集系統(tǒng)，用于從樹木中真空采集花粉。這些依賴于用真空和過(guò)濾系統(tǒng)包圍樹木，同時(shí)使用樹木搖床釋放花粉（橄欖[30]，落葉松[54]）。這些機(jī)械化系統(tǒng)可以收獲的花粉量是手持真空設(shè)備的十倍，盡管花粉的質(zhì)量往往較低[54]。
Different processes are explored in Figure 3.
After collection and processing, binucleate pollen can be put into cold storage and kept viable, often for several years. Storage conditions for particular species have been explored thoroughly in the literature on germplasm maintenance and plant breeding (recently reviewed by [58]). As long as the cold chain is maintained, it is not uncommon to be able to store pollen at ?20 °C for 1–6 years with little loss of viability [23,28,58], giving producers flexibility to apply pollen from one year to the next, helping to mitigate synchronicity and production risks.
圖3探討了不同的過(guò)程。
經(jīng)過(guò)收集和處理后，雙核花粉可以冷藏保存，通?？梢员４鏀?shù)年。在種質(zhì)資源維護(hù)和植物育種的文獻(xiàn)中，對(duì)特定物種的儲(chǔ)存條件進(jìn)行了深入探討（最近由[58]綜述）。只要冷鏈得以維持，能夠在-20°C下儲(chǔ)存花粉1-6年而幾乎不損失活力的情況并不罕見[23,28,58]，這使生產(chǎn)者能夠靈活地將花粉從一年應(yīng)用到下一年，有助于降低同步性和生產(chǎn)風(fēng)險(xiǎn)。
3. Pollen Application3.花粉施用
Many methods to pollinate plants have been explored. Broadly, there are two main approaches: pollen can be applied dry (possibly diluted with a neutral carrier, such as charcoal, to help manage application rates), or wet (generally suspended in an aqueous liquid, often with additives to ensure isotonic balance with pollen cells) (Figure 4). A third option is available for selected, self-compatible crops—such as tomato—where vibrating the floral structures, either through direct contact or with a puff of air, shakes loose pollen to fertilize the flower [59].
人們已經(jīng)探索了許多給植物授粉的方法。從廣義上講，有兩種主要方法：花粉可以干施（可能用中性載體如木炭稀釋，以幫助控制施用量），也可以濕施（通常懸浮在水性液體中，通常含有添加劑以確保與花粉細(xì)胞的等滲平衡）（圖4）。第三種選擇適用于選定的自兼容作物，如番茄，通過(guò)直接接觸或一股空氣振動(dòng)花朵結(jié)構(gòu)，搖動(dòng)松散的花粉使花朵受精[59]。
Most application literature measures results directly in terms of fruit or seed set, as pollen requirements have been characterized for relatively few crops [60,61,62,63]. Research has shown that liquid-carrier (or dry diluent composition) formulation, temperature, time of day, weather, stigma receptivity, and flower age all influence pollination efficacy [41,61,64,65,66,67,68]. These factors are largely ignored in much of the work published on alternative pollination systems.
大多數(shù)應(yīng)用文獻(xiàn)的測(cè)量結(jié)果直接與果實(shí)或結(jié)實(shí)有關(guān)，因?yàn)榛ǚ坌枨蟮奶卣魇窍鄬?duì)較少的作物[60,61,62,63]。研究表明，液體載體（或干稀釋劑組合物）配方、溫度、時(shí)間、天氣、柱頭接受性和花齡都會(huì)影響授粉效果[41,61,64,65,66,67,68]。在許多關(guān)于替代授粉系統(tǒng)的研究中，這些因素在很大程度上被忽視了。
Dry application has two important advantages over wet pollen application:
干施比濕施花粉有兩個(gè)重要優(yōu)點(diǎn)：
Dry pollen delivered to non-target areas (e.g., petals, leaves) often remains viable and can be redistributed to the stigmas by bees [69], while pollen remains viable only for a short time once it becomes wet (30–100 min; [15,70]);
遞送到非目標(biāo)區(qū)域（如花瓣、葉子）的干花粉通常仍然存活，并可以被蜜蜂重新分配到柱頭[69]，而花粉一旦變濕，只能在短時(shí)間內(nèi)存活（30-100分鐘；[15,70]）；
Suitable aqueous carrier solutions have been demonstrated for kiwifruit [36], cherry [70], pear [71,72], pistachio [32], and date palm [28], but new solutions must be created, or customized, and validated for each crop.
獼猴桃[36]、櫻桃[70]、梨[71,72]、開心果[32]和椰棗[28]已經(jīng)證明了合適的水性載體溶液，但必須為每種作物創(chuàng)造、定制和驗(yàn)證新的溶液。
Insect pollinators take advantage of naturally occurring electrostatic forces, which help transfer pollen from bee to flower [73]. Research and commercial application have demonstrated that electrostatically charging dry pollen can improve the proportion captured by the flower by 5- to 10-fold [70,74,75,76]. However, droplets in aqueous systems generally have larger mass, making it more difficult to attach a sufficient charge to the pollen to affect its trajectory.
昆蟲傳粉者利用自然產(chǎn)生的靜電力，這有助于將花粉從蜜蜂轉(zhuǎn)移到花朵[73]。研究和商業(yè)應(yīng)用表明，帶靜電的干花粉可以將花朵捕獲的比例提高5到10倍[70,74,75,76]。然而，水性系統(tǒng)中的液滴通常具有更大的質(zhì)量，這使得更難在花粉上附著足夠的電荷來(lái)影響其軌跡。
The main advantages of aqueous systems are:
水性系統(tǒng)的主要優(yōu)點(diǎn)是：
Enabling more targeted delivery, efficacy during damp conditions where insect pollinators may be scarce [15,23,38];
在昆蟲傳粉者可能稀缺的潮濕條件下實(shí)現(xiàn)更有針對(duì)性的遞送和療效[15,23,38]；
The additional liquid mass increases momentum for targeted delivery, reducing the risk the pollen is dispersed by wind.
額外的液體質(zhì)量增加了靶向遞送的動(dòng)量，降低了花粉被風(fēng)吹散的風(fēng)險(xiǎn)。
The majority of the artificial pollination systems in Figure 4 are used to supplement available bees, but for some crops, these systems perform adequately by themselves, including kiwifruit [16,19,23,77,78,79,80], olive [23], date palm [28], walnut [33,81], tomato [59], and hybrid maize seed [35].
圖4中的大多數(shù)人工授粉系統(tǒng)用于補(bǔ)充可用的蜜蜂，但對(duì)于某些作物，這些系統(tǒng)本身就可以充分發(fā)揮作用，包括獼猴桃[16,19,23,77,78,79,80]、橄欖[23]、椰棗[28]、核桃[33,81]、番茄[59]和雜交玉米種子[35]。
In cases where insect pollinators are abundant, bees perform equivalently or better than artificial pollination for kiwifruit [56,82,83] and kiwiberry [84,85], but when conditions are not optimal, particularly in years where local conditions limit pollinator activity, correctly applied supplemental pollination can increase seed number and fruit size [16,19,23,78,79,80]. Pollen is typically applied in two or more passes through the orchard [86], but a single pass at petal fall has been effective in Italian kiwifruit orchards [23].
在昆蟲傳粉者豐富的情況下，蜜蜂對(duì)獼猴桃[56,82,83]和獼猴桃[84,85]的授粉效果與人工授粉相當(dāng)或更好，但當(dāng)條件不是最佳時(shí)，特別是在當(dāng)?shù)貤l件限制傳粉者活動(dòng)的年份，正確應(yīng)用補(bǔ)充授粉可以增加種子數(shù)量和果實(shí)大小[16,19,23,78,79,80]。花粉通常在果園中分兩次或多次施用[86]，但在意大利獼猴桃果園中，花瓣落下時(shí)單次施用是有效的[23]。
3.1. Hand-Pollination
Manual pollination with a paintbrush, stick, or pole tipped with a feather-brush is labour-intensive [12,23,41,87]. This cost can be sustained by some high-value crops (Table 1) [11], particularly when pollen does not need to be collected (e.g., tomato), the pollen is produced in abundance and collection costs are low (e.g., date), or the market value of the crop is very high (e.g., vanilla). Where mechanisation is available (even if only in the form of a vibratory wand), it is often more effective and economical than manual pollination [23,59,72,86,87].
3.1. 人工授粉
用畫筆、棍子或羽毛刷尖端的桿子進(jìn)行人工授粉是勞動(dòng)密集型的[12,23,41,87]。一些高價(jià)值作物可以承受這種成本（表1）[11]，特別是在不需要收集花粉（如番茄）、花粉大量生產(chǎn)且收集成本低（如棗）或作物的市場(chǎng)價(jià)值很高（如香草）的情況下。在機(jī)械化可用的情況下（即使只是以振動(dòng)棒的形式），它通常比人工授粉更有效、更經(jīng)濟(jì)[23,59,72,86,87]。
3.2. Handheld Devices
Handheld devices, such as blowers, sprayers, and vibratory wands, are quicker and easier to use for applying pollen than simple hand tools, such as paintbrushes, significantly reducing labour costs. Within these technologies is a constellation of inventive processes, but we found that four general categories of applicators are commonly used in commercial settings: vibratory wands (particularly for indoor tomato production); pneumatic devices tipped with a brush or feather-brush (for orchard crops); handheld blowers (often utilising commercial leaf blowers as a base component); and modified agricultural sprayers (Table 2). Directed broadcast of pollen using a handheld leaf blower has been estimated to deliver only 1% of pollen to stigmatic surfaces [101]; for dry application, some of the remaining 99% may then be redistributed by bees [69]. Other approaches have been explored, including a bubble gun [102], and a handheld electrostatic pollinator that can both collect and apply pollen [103]. However, both require further research to overcome the technical challenges (e.g., poor targeting and damage to floral structures from coronal discharge) before they could become commercial realities. A different handheld electrostatic pollinator was used successfully for the indoor cultivation of hybrid larch seed, but requires an external pollen supply [31].
3.2. 手持裝置
手持式設(shè)備，如鼓風(fēng)機(jī)、噴霧器和振動(dòng)棒，比簡(jiǎn)單的手動(dòng)工具（如畫筆）更快、更容易用于施加花粉，大大降低了勞動(dòng)力成本。在這些技術(shù)中，有一系列創(chuàng)造性的工藝，但我們發(fā)現(xiàn)，在商業(yè)環(huán)境中通常使用四類施用器：振動(dòng)棒（特別是用于室內(nèi)番茄生產(chǎn)）；帶刷子或羽毛刷的氣動(dòng)裝置（用于果園作物）；手持式鼓風(fēng)機(jī)（通常使用商用吹葉機(jī)作為基礎(chǔ)組件）；以及改良的農(nóng)業(yè)噴霧器（表2）。據(jù)估計(jì)，使用手持式吹葉機(jī)定向傳播花粉只能將1%的花粉輸送到柱頭表面[101]；對(duì)于干施，剩下的99%中的一部分可能會(huì)被蜜蜂重新分配[69]。已經(jīng)探索了其他方法，包括氣泡槍[102]和可以收集和施用花粉的手持式靜電授粉器[103]。然而，在它們成為商業(yè)現(xiàn)實(shí)之前，兩者都需要進(jìn)一步的研究來(lái)克服技術(shù)挑戰(zhàn)（例如，靶向性差和冠狀放電對(duì)花結(jié)構(gòu)的破壞）。另一種手持式靜電授粉器已成功用于雜交落葉松種子的室內(nèi)栽培，但需要外部花粉供應(yīng)[31]。
3.3. Vehicle-Mounted Devices
Sprayers, blowers, and fans of various kinds have been developed for large-scale pollination (Table 3). These devices require far fewer person-hours than equivalent handheld devices [28,86]. Early trials with apples used spray planes [26], and broadcast tractor sprayers [27]). In kiwifruit, broadcast systems were developed in the 1980s and had significant uptake by growers in the USA, Italy, and New Zealand for supplementing insect pollinators (replacing them in Italy, southern China, and Korea [16,17,18,19]) owing to their lower labour costs than hand application. In the Middle East, several inventions, including directed high-pressure sprayers drawn by tractors [28], have also performed as well as or better than the standard practice of manually pollinating date palm. Most of these devices are made to be towed behind a tractor, but some are also able to be mounted on farm ATVs for increased manoeuvrability, or on autonomous robotic platforms to reduce operator costs (e.g., XAG’s R150, Guangzhou, Guangdong, China, a small, multipurpose autonomous spraying and mowing robot). XAG’s ground-based pollen sprayer traversed a row of an apple orchard in 10 min, while hand pollination would take more than 2 h; however, pollination efficacy was not reported [93]. Broadcast wet sprayers are considered a last resort for pollination, and have lower efficiency in kiwifruit than dry applicators unless high rates of pollen are used [23], and also failed to deposit any pollen on the stigma of the much smaller Japanese plum flowers [14].
3.3. 車載設(shè)備
已經(jīng)開發(fā)了各種噴霧器、鼓風(fēng)機(jī)和風(fēng)扇，用于大規(guī)模授粉（表3）。這些設(shè)備所需的人時(shí)比同等的手持設(shè)備少得多[28,86]。早期對(duì)蘋果的試驗(yàn)使用了噴霧機(jī)[26]和廣播拖拉機(jī)噴霧器[27]）。在獼猴桃中，廣播系統(tǒng)是在20世紀(jì)80年代開發(fā)的，由于其比手工應(yīng)用更低的勞動(dòng)力成本，美國(guó)、意大利和新西蘭的種植者大量采用該系統(tǒng)來(lái)補(bǔ)充昆蟲傳粉者（在意大利、中國(guó)南方和韓國(guó)取代了它們[16,17,18,19]）。在中東，一些發(fā)明，包括拖拉機(jī)牽引的定向高壓噴霧器[28]，也與人工授粉椰棗的標(biāo)準(zhǔn)做法一樣好或更好。這些設(shè)備中的大多數(shù)都是拖在拖拉機(jī)后面的，但也有一些能夠安裝在農(nóng)場(chǎng)ATV上以提高機(jī)動(dòng)性，或者安裝在自主機(jī)器人平臺(tái)上以降低操作員成本（例如，XAG的R150，中國(guó)廣東廣州，一種小型多用途自主噴灑和割草機(jī)器人）。XAG的地面花粉噴霧器在10分鐘內(nèi)穿過(guò)一排蘋果園，而人工授粉需要2個(gè)多小時(shí)；然而，沒(méi)有報(bào)道授粉效果[93]。噴灑式濕式噴霧器被認(rèn)為是授粉的最后手段，除非使用高花粉率，否則在獼猴桃上的效率低于干式噴霧器[23]，而且也沒(méi)有在小得多的日本梅花的柱頭上沉積任何花粉[14]。
By their nature, non-targeted systems are wasteful, as pollen grains that settle on leaves, orchard structures, and branches do not fertilise the flower (pollen grains that land on petals, which can be redistributed by bees, are in the minority). To address this, researchers have investigated directed broadcast of electrostatically charged pollen, primarily for almonds, but also for apple, pear, sweet cherry, kiwifruit, and pistachio. Directing the pollen into the canopy reduces the amount of pollen lost to the wider environment, while positively charging the pollen increases attraction to pointed structures (such as styles), increasing pollen deposition [108]. Most of the work investigating electrostatic charge in pollination has involved an Israeli group led by Gan-Mor [74,75,108], and two US groups [109,110]. The application of electrostatic charge has increased pollen deposition on stigmas and improved the fruit set of almond, pistachio, date, apple, cherry, and pear under poor pollination conditions [70,94,110]. In general, for insect-pollinated crops other than kiwifruit and date palm, broadcast pollination is applied in addition to bee pollination, where it may improve fruit or nut set in years where pollination is poor [70,110]. However, there have been few studies on the effects of electrostatically charged pollen application on insect-pollinated crops without the assistance of bees; a trial from the grey literature suggests that the systems are no substitute for insect pollinators—almond yields were 1.3% without pollination, 17% with electrostatic pollination, and over 50% with insect pollination [111].
從本質(zhì)上講，非目標(biāo)系統(tǒng)是浪費(fèi)的，因?yàn)槁湓谌~子、果園結(jié)構(gòu)和樹枝上的花粉粒不會(huì)給花施肥（落在花瓣上的花粉顆粒是少數(shù)，可以被蜜蜂重新分配）。為了解決這個(gè)問(wèn)題，研究人員研究了帶靜電花粉的定向傳播，主要用于杏仁，也用于蘋果、梨、甜櫻桃、獼猴桃和開心果。將花粉引入樹冠可以減少花粉流失到更廣泛環(huán)境中的量，而帶正電的花粉可以增加對(duì)尖端結(jié)構(gòu)（如花柱）的吸引力，增加花粉沉積[108]。研究授粉中靜電荷的大部分工作都涉及由Gan-Mor領(lǐng)導(dǎo)的以色列小組[74,75108]和兩個(gè)美國(guó)小組[109110]。在授粉條件較差的情況下，施加靜電荷增加了柱頭上的花粉沉積，并改善了杏仁、開心果、棗、蘋果、櫻桃和梨的坐果率[70,94110]。一般來(lái)說(shuō)，對(duì)于獼猴桃和椰棗以外的昆蟲授粉作物，除了蜜蜂授粉外，還應(yīng)用了廣播授粉，這可能會(huì)在授粉不良的年份提高果實(shí)或堅(jiān)果的結(jié)實(shí)率[70110]。然而，在沒(méi)有蜜蜂幫助的情況下，關(guān)于靜電花粉施用對(duì)昆蟲授粉作物的影響的研究很少；灰色文獻(xiàn)的一項(xiàng)試驗(yàn)表明，這些系統(tǒng)不能替代昆蟲傳粉者——不授粉時(shí)杏仁產(chǎn)量為1.3%，靜電授粉時(shí)為17%，昆蟲授粉時(shí)為50%以上[111]。
Table 3
Representative pollination devices mounted to tractors with and without electrostatic charge capability.
表3
安裝在具有和不具有靜電荷能力的拖拉機(jī)上的代表性授粉裝置。
| Mode | General Type | Examples | References |
|---|---|---|---|
| Vibration | Fan | Ventola, Italy | [23,41] |
| Dry | Pollen blowers | QuadDuster, KiwiPollen, New Zealand?AirShear, KiwiPollen, New Zealand?PollenSmart, PollenSmart, New ZealandATV Applicator, PollenPro, USAScumby, Firman Pollen, USA [112]Palm Tree Pollination Machine, AgroPalms Machinery, Spain | [107][41][113][112][28,114,115] |
| Electrostatic pollen blowers | Home-made devicesEdete | [116][95] | |
| Wet | High-pressure sprayers | Palm Tree Pollination Machine, Agrom Agro Machinery, IL | [28] |
| Fogger/fine mist sprayers | Kiwi Pollen Boom Sprayer, KiwiPollen, New Zealand?Spruzz@Polline TR, Gerbaudo, Cuneo, Italy?XAG R150, China | [38][23,93] | |
| Electrostatic sprayers | Electrostatic Spraying Systems, Inc., USAOnTarget, On Target Spray Systems, USA?Fruit Tower, LectroBlast, USA | [111][117][116][93] |
3.4. Unmanned Aerial Vehicles (UAVs)
Drone-based pollination technology has received considerable attention (Table 4). The use of drones to pollinate crops is an attractive proposition both because drones have a good aesthetic fit for the job—they are airborne pollinators, like bees—and because drone technology has a lower barrier to entry than other forms of robotics [118]. These devices are either directly controlled by a pilot, follow a set path defined by the layout of orchard rows, or utilise a 3-D model of the environment built from an earlier pass by scouting drones [119]. Many drone pollinators are modifications of commercially available drones, particularly those designed for agrichemical sprays (e.g., [51,81,120]), but a number are also being custom-designed for pollination. Several pollination modes are being explored, including aerial broadcast distribution of pollen (Table 4), as well as utilising the drone’s air vortices for pollination directly for hybrid grain production and glasshouse-grown self-compatible crops such as strawberry, tomato, pepper, and eggplant [121,122]. Other approaches have also been prototyped, including a microdrone with a fur pad for direct contact pollination [123], and a drone equipped with a bubble gun [102], but the drawbacks to both approaches—time in the first case and accuracy in the second—may limit their applicability in field situations. Indeed, contact-style drones have been criticised for trying to emulate bees too closely: it is neither practicable nor desirable to create tens of thousands of microdrones to replace a single honey bee colony [124,125], let alone the thousands of colonies used each year for intensive commercial cropping. Aerial broadcast approaches are likely to have the same limitations as ground-based broadcasts, with only a small portion of the pollen dispensed reaching the stigma where it can contribute to pollination.
3.4. 無(wú)人機(jī)
基于無(wú)人機(jī)的授粉技術(shù)受到了相當(dāng)大的關(guān)注（表4）。使用無(wú)人機(jī)為作物授粉是一個(gè)有吸引力的提議，這既是因?yàn)闊o(wú)人機(jī)具有很好的美學(xué)適合這項(xiàng)工作——它們是空中授粉者，就像蜜蜂一樣——也是因?yàn)闊o(wú)人機(jī)技術(shù)的進(jìn)入門檻比其他形式的機(jī)器人低[118]。這些設(shè)備要么由飛行員直接控制，要么遵循果園行布局定義的設(shè)定路徑，要么利用偵察無(wú)人機(jī)從早期通行中構(gòu)建的環(huán)境三維模型[119]。許多無(wú)人機(jī)傳粉者是對(duì)商用無(wú)人機(jī)的改進(jìn)，特別是那些專為農(nóng)用化學(xué)品噴霧而設(shè)計(jì)的無(wú)人機(jī)（例如[51,8112]），但也有一些是為授粉而定制的。目前正在探索幾種授粉方式，包括空中傳播花粉（表4），以及利用無(wú)人機(jī)的空氣渦流直接為雜交谷物生產(chǎn)和溫室種植的草莓、番茄、辣椒和茄子等自交作物授粉[121122]。其他方法也已經(jīng)原型化，包括帶有毛皮墊的微型飛行器用于直接接觸授粉[123]，以及配備氣泡槍的無(wú)人機(jī)[102]，但這兩種方法的缺點(diǎn)——第一種方法的時(shí)間和第二種方法的準(zhǔn)確性——可能會(huì)限制它們?cè)诂F(xiàn)場(chǎng)情況下的適用性。事實(shí)上，接觸式無(wú)人機(jī)因試圖過(guò)于接近蜜蜂而受到批評(píng)：制造數(shù)萬(wàn)個(gè)微芯片來(lái)取代一個(gè)蜜蜂群落既不可行也不可取[124125]，更不用說(shuō)每年用于密集商業(yè)種植的數(shù)千個(gè)蜂群了?？罩袕V播方法可能與地面廣播具有相同的局限性，只有一小部分分配的花粉到達(dá)可以促進(jìn)授粉的柱頭。
Drone pollinators have seen a degree of commercial success in date palm pollination, historically pollinated by hand, by humans scaling the palm trees. As these trees produce copious quantities of pollen, there is little concern about waste from broadcast application [108], and the increase in time savings and improved safety from reducing tree climbing are significant [28,119,120]. Walnut pollination is another emerging area, with positive initial results in multiple countries, producing walnut kernels equivalent to those from wind-pollinated controls [33,81]. Dropcopter is the most well-known organization in this field. They provide pollination services to several crops (Table 4), including apple, cherry, and almond, reporting 53%, 40%, and 94% higher fruit set, respectively, over grower standard methods. However, little independent information about this system’s efficacy (and those of most commercial drone offerings) is available to date.
無(wú)人機(jī)授粉者在椰棗授粉方面取得了一定程度的商業(yè)成功，歷史上是由人類攀爬棕櫚樹手工授粉的。由于這些樹木會(huì)產(chǎn)生大量的花粉，因此很少有人擔(dān)心廣播應(yīng)用的浪費(fèi)[108]，減少爬樹可以節(jié)省大量時(shí)間并提高安全性[28119120]。核桃授粉是另一個(gè)新興領(lǐng)域，在多個(gè)國(guó)家取得了積極的初步成果，生產(chǎn)的核桃仁與風(fēng)媒授粉對(duì)照的核桃仁相當(dāng)[33,81]。Dropcopter是該領(lǐng)域最知名的組織。它們?yōu)槎喾N作物提供授粉服務(wù)（表4），包括蘋果、櫻桃和杏仁，其坐果率分別比種植者標(biāo)準(zhǔn)方法高53%、40%和94%。然而，迄今為止，關(guān)于該系統(tǒng)的功效（以及大多數(shù)商用無(wú)人機(jī)產(chǎn)品的功效）的獨(dú)立信息很少。
Drones have considerable promise in tall tree crops where their ability to dispense pollen above the canopy is an advantage, with potential applications in conifer breeding [129] as well as wind-pollinated nut crops, which have shown promise in artificial pollination trials, including hazelnut, pistachio, and walnut [25,33,81].
無(wú)人機(jī)在高大樹木作物中具有相當(dāng)大的前景，它們?cè)跇涔谏戏椒峙浠ǚ鄣哪芰κ且粋€(gè)優(yōu)勢(shì)，在針葉樹育種[129]以及風(fēng)媒授粉的堅(jiān)果作物中都有潛在的應(yīng)用，這些作物在人工授粉試驗(yàn)中顯示出希望，包括榛子、開心果和核桃[25,33,81]。
3.5. Robotics and Autonomous Pollination
Autonomous robotic pollinators are often designed to target individual flowers for to minimize waste. Generally, machine vision is used to identify a flower that requires pollination. Broadly, two approaches to delivering pollen have been explored: moving an end-effector close to the flower, or spraying pollen from a distance. Several methods to apply pollen with an end-effector have been explored, including using a robot arm to brush the flower with pollen, touching the flower with a vibrating rod, and delivering a tuned vibration or air-blast to distribute pollen. Aside from brushing pollen, these methods apply only to crops that are self-fertile (e.g., tomato). Pollen sprayed from a distance can be delivered wet or dry.
3.5. 機(jī)器人與自主授粉
自主機(jī)器人傳粉者通常被設(shè)計(jì)為針對(duì)單個(gè)花朵，以盡量減少浪費(fèi)。通常，機(jī)器視覺(jué)用于識(shí)別需要授粉的花朵。從廣義上講，已經(jīng)探索了兩種傳遞花粉的方法：將末端效應(yīng)器靠近花朵，或從遠(yuǎn)處噴灑花粉。已經(jīng)探索了幾種使用末端執(zhí)行器施加花粉的方法，包括使用機(jī)器人手臂用花粉刷花，用振動(dòng)棒觸摸花，以及傳遞調(diào)諧振動(dòng)或氣流來(lái)分配花粉。除了刷花粉外，這些方法僅適用于自育作物（如番茄）。從遠(yuǎn)處噴灑的花粉可以濕送或干送。
Machine-vision systems employing deep learning can locate objects in images with 90%, or higher, accuracy, and with processing rates of up to 100 frames/s [97,130,131,132,133]. Systems employing robotic arms tend to be relatively slow. For example, research on a tomato pollination robot reported pollination speeds of 15–20 s per flower, rates that are not practical for pollination of commercial-scale crops [134,135,136]. Several systems that have already been commercialised are quicker—achieving application rates of about 2–5 s per flower cluster [137]—using several arms to pollinate multiple flowers at once and air-jets to reduce the fine motor control required to position end-effectors directly on a flower. For example, Arugga AI incorporate four sets of nozzles to pollinate high-wire tomato [98]. However, systems employing arms to move an end-effector close to the flower have been used only in greenhouse applications to date (Table 5). Field applications tend to favour spraying systems, delivering a dose of pollen from a vehicle moving through the crop. For example, PowerPollen are running commercial trials with a tractor-mounted boom holding 16 parallel autonomous pollinators for maize. The system mechanically funnels maize silks into the autonomous pollinator’s spray region and deliveries a dose of electrostatically charged dry pollen as the tractor traverses the crop rows [35].
采用深度學(xué)習(xí)的機(jī)器視覺(jué)系統(tǒng)可以以90%或更高的精度在圖像中定位物體，處理速率高達(dá)100幀/秒[9713013132133]。采用機(jī)械臂的系統(tǒng)往往相對(duì)較慢。例如，對(duì)番茄授粉機(jī)器人的研究報(bào)告稱，每朵花的授粉速度為15-20s，這一速度對(duì)于商業(yè)規(guī)模作物的授粉是不切實(shí)際的[134135136]。幾個(gè)已經(jīng)商業(yè)化的系統(tǒng)更快——每個(gè)花簇的施用率約為2-5s[137]——使用多個(gè)臂同時(shí)為多朵花授粉，并使用空氣噴射器減少將末端執(zhí)行器直接放置在花上所需的精細(xì)運(yùn)動(dòng)控制。例如，Arugga AI結(jié)合了四組噴嘴來(lái)為高架番茄授粉[98]。然而，迄今為止，使用臂將末端執(zhí)行器移動(dòng)到花朵附近的系統(tǒng)僅在溫室應(yīng)用中使用（表5）。田間應(yīng)用往往傾向于噴霧系統(tǒng)，從穿過(guò)作物的車輛中輸送一定劑量的花粉。例如，PowerPollen正在進(jìn)行商業(yè)試驗(yàn)，其拖拉機(jī)上安裝的吊桿上裝有16個(gè)平行的玉米自主傳粉者。該系統(tǒng)將玉米絲機(jī)械地輸送到自主授粉者的噴灑區(qū)域，并在拖拉機(jī)穿過(guò)作物行時(shí)輸送一劑帶靜電的干花粉[35]。
Autonomous robotic pollinators equipped with expert-informed targeting systems could identify and target flowers that produce the best fruit, enabling intelligent pollination services—a possibility suggested by Verdant Robotics’ patented apple pollinator and flower thinner (US11308323B2). Unfortunately, very few data are available about the pollination efficacies of the above devices. The prototype ultrasonic strawberry pollinator was able to perform better than hand pollination [99], while the prototype tomato pollinator performed substantially worse [134]. PowerPollen reported success in hybrid maize production, with a 20% boost in seed yield over current practice [35].
配備有專家信息定位系統(tǒng)的自主機(jī)器人傳粉者可以識(shí)別和定位產(chǎn)生最佳果實(shí)的花朵，從而實(shí)現(xiàn)智能授粉服務(wù)——Verdant Robotics的專利蘋果傳粉者和花朵稀釋劑（US11308323B2）提出了這種可能性。不幸的是，關(guān)于上述設(shè)備的授粉效率，可用的數(shù)據(jù)很少。原型超聲波草莓傳粉者能夠比手工授粉表現(xiàn)更好[99]，而原型番茄傳粉者的表現(xiàn)要差得多[134]。PowerPollen報(bào)道了雜交玉米生產(chǎn)的成功，種子產(chǎn)量比目前的做法提高了20%[35]。
Pollen delivered in an aqueous suspension, sprayed from a moving platform, has demonstrated speeds more practical for intensive commercial cropping [77]. In 2019, during field trials of the autonomous research prototype robot, the machine fully pollinated >670 export-quality “Hayward” kiwifruit, without contribution from insect pollinators, from a platform moving at 2.5 km/h. Key metrics (fruit set, seed count, fruit weight) were comparable to those of insect-pollinated control samples [77]. However, the authors cited high pollen usage (3–5 kg/ha), the associated labour cost to collect the pollen, and relatively slow speed as some of the challenges to be overcome before practical commercial application.
從移動(dòng)平臺(tái)噴灑的水懸浮液中輸送的花粉，已經(jīng)證明其速度更適合密集的商業(yè)種植[77]。2019年，在自主研究原型機(jī)器人的田間試驗(yàn)中，該機(jī)器從以2.5公里/小時(shí)的速度移動(dòng)的平臺(tái)上完全授粉了670多個(gè)出口質(zhì)量的“海沃德”獼猴桃，沒(méi)有昆蟲授粉者的貢獻(xiàn)。關(guān)鍵指標(biāo)（坐果、種子數(shù)、果實(shí)重量）與昆蟲授粉的對(duì)照樣本相當(dāng)[77]。然而，作者指出，在實(shí)際商業(yè)應(yīng)用之前，需要克服的一些挑戰(zhàn)包括花粉使用量高（3-5kg/ha）、收集花粉的相關(guān)勞動(dòng)力成本和相對(duì)較慢的速度。
4. Conclusions
Artificial pollination is currently used to supplement insect pollinators for a variety of cropping systems. The rare cases where artificial pollination is used instead of insect pollinators are generally characterized by particular features that make natural pollination difficult, such as a lack of natural pollinators (vanilla, cherimoya, date palm) or dioecy combined with abundant pollen (e.g., kiwifruit, pistachio), or, conversely, are those that are easily self-pollinated by agitation alone (e.g., tomato, strawberry). A variety of devices are being developed and are used commercially to pollinate crops, with increasing focus on drone- and robotics-based solutions.
4.結(jié)論
人工授粉目前用于補(bǔ)充各種種植系統(tǒng)的昆蟲傳粉者。使用人工授粉而不是昆蟲授粉的罕見情況通常具有使自然授粉困難的特定特征，例如缺乏天然授粉者（香草、番荔枝、椰棗）或結(jié)合大量花粉的雌雄異株（如獼猴桃、開心果），或者相反，是那些僅通過(guò)攪拌就容易自花授粉的情況（如番茄、草莓）。正在開發(fā)各種設(shè)備，并將其用于商業(yè)作物授粉，越來(lái)越多地關(guān)注基于無(wú)人機(jī)和機(jī)器人的解決方案。
However, many challenges remain. Insects are full-service pollinators collecting, transporting and delivering a portion of the pollen they collect while foraging. They reproduce quickly, easily producing thousands of “workers” each year, and thus provide the scale needed for intensive commercial cropping systems. Yet, like many ecosystem services, their contribution to food production is threatened. Most artificial pollination research to date treats pollen as a system input and its delivery as the final output. Pollen is available at commercial scale for a limited number of crops globally, and its availability is driven largely by quantified benefits for supplementing natural pollinators. Little research has been found on the collection, processing and management of pollen for artificial pollination in many crops. Perhaps because of the lack of clear commercial benefit and practical methods for application, harvesting pollen is of limited value for all but the highest-value crops. Nevertheless, the increased activity in research and commercial applications over the last decade signals growing appreciation for the vital role pollination services play in agricultural food production systems.
然而，許多挑戰(zhàn)仍然存在。昆蟲是全方位服務(wù)的傳粉者，在覓食時(shí)收集、運(yùn)輸和遞送部分花粉。它們繁殖迅速，每年很容易產(chǎn)生數(shù)千名“工人”，從而為密集的商業(yè)種植系統(tǒng)提供了所需的規(guī)模。然而，與許多生態(tài)系統(tǒng)服務(wù)一樣，它們對(duì)糧食生產(chǎn)的貢獻(xiàn)受到了威脅。迄今為止，大多數(shù)人工授粉研究都將花粉視為系統(tǒng)輸入，將其傳遞視為最終輸出。全球范圍內(nèi)，花粉在商業(yè)規(guī)模上可用于有限數(shù)量的作物，其可用性在很大程度上是由補(bǔ)充天然傳粉者的量化益處驅(qū)動(dòng)的。在許多作物中，關(guān)于人工授粉花粉的收集、加工和管理的研究很少。也許是因?yàn)槿狈γ鞔_的商業(yè)效益和實(shí)用的應(yīng)用方法，除了價(jià)值最高的作物外，采集花粉對(duì)所有作物的價(jià)值都是有限的。然而，過(guò)去十年研究和商業(yè)應(yīng)用活動(dòng)的增加表明，人們?cè)絹?lái)越認(rèn)識(shí)到授粉服務(wù)在農(nóng)業(yè)糧食生產(chǎn)系統(tǒng)中發(fā)揮的重要作用。
Conceptualization, M.A.B., M.C. and P.M.: methodology, M.A.B. and P.M.; formal analysis, M.A.B.; investigation, M.A.B. and P.M.; data curation, M.A.B.; writing—original draft preparation, M.A.B.; writing—review and editing, M.A.B., M.C. and P.M.; visualization, M.A.B.; supervision, M.A.B.; project administration, M.A.B.; funding acquisition, M.A.B. All authors have read and agreed to the published version of the manuscript.
概念化，M.A.B.、M.C.和P.M.：方法論，M.A.B和P.M。；形式分析，M.A.B。；調(diào)查，M.A.B.和P.M。；數(shù)據(jù)管理，M.A.B。；寫作——初稿編寫，M.A.B。；寫作——審查和編輯，文學(xué)碩士、文學(xué)碩士和下午。；可視化，M.A.B。；監(jiān)督，M.A.B。；項(xiàng)目管理碩士。；所有作者均已閱讀并同意手稿的出版版本。
We thank Claudia Adams for running the initial patent search, and Warrick Nelson, Monica Holland, Max Buxton, David Pattemore, Nico Bordes, and Anne Gunson for providing a critical review of the manuscript. We also thank three anonymous reviewers for their helpful comments on the manuscript.
我們感謝Claudia Adams進(jìn)行了初步的專利檢索，并感謝Warrick Nelson、Monica Holland、Max Buxton、David Pattemore、Nico Bordes和Anne Gunson對(duì)手稿進(jìn)行了批判性審查。我們也感謝三位匿名審稿人對(duì)手稿的寶貴意見。
The authors declare no conflict of interest. All authors have participated in the development of artificial pollination technology. The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript; or in the decision to publish the results.
作者聲明沒(méi)有利益沖突。所有作者都參與了人工授粉技術(shù)的發(fā)展。資助者在研究設(shè)計(jì)中沒(méi)有任何作用；收集、分析或解釋數(shù)據(jù)；在撰寫手稿時(shí)；或者在決定公布結(jié)果時(shí)。
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