Humans have a strange fascination with flowers. From the multi‐billion dollar cut‐flower industry where flowers are bred, grown, admired, and then thrown away to the houses of Christian Dior and Yves Saint Laurent, where floral extracts are used to make us smell less like mammals and more like plants, our flower obsession makes it easy to forget that they evolved not to beguile us, but primarily to facilitate pollen movement from anthers to stigmas. Despite a torrent of pollination studies since Darwin (1862), pollen movement, one of the most important aspects of pollination, remains one of its hardest to quantify (Minnaar et al., 2019a). The pollen journey from anther to ovule is like an obstacle course, with barriers, hurdles, twists, and turns (Inouye et al., 1994). With so many possible outcomes, it is difficult to determine why some pollen grains make it through the course but others get held up or lost along the way (Minnaar et al., 2019a). However, if biologists could label and distinguish cohorts of identical‐looking pollen grains from separate flowers, and then recapture those labelled grains at different points along the obstacle course, we could begin to trace the complex pathway leading to pollen success or failure. Although molecular tools can determine the pollen parent of seeds, difficulties in sequencing pollen (but see Matsuki et al., 2007) and applying labels to many of them, mean that the fates of most pollen grains (>98% of which do not fertilize seeds; Harder and Thomson, 1989) remain mysterious.

Two breakthroughs provide us with new tools to follow grains. The first is the ability to determine the genotypes of individual pollen grains (Matsuki et al., 2007; Hasegawa et al., 2015). The second is the application of quantum dot nanotechnology as fluorescent pollen markers (Minnaar and Anderson, 2019). Quantum dots (Q‐dots) are crystals of semiconductor metals, so small (10,000 Q‐dots span the width of a human hair) that they behave somewhat like atoms (Gammon, 2000). When exposed to ultraviolet light, their electrons jump excitedly between states, emitting super‐bright photons of light (Ekimov, 1991). By fine‐tuning Q‐dot size, the color of the emitted light can be altered (Yoffe, 2001). Q‐dots covered in a fatty‐acid coating can then be attached to pollen grains simply by suspending them in solution and applying the solution to anthers using a pipette. UV illumination can then be used to distinguish pollen grains labelled with different colors after they have been deposited on stigmas or pollinators (Fig. 1). Q‐dots have advantages over traditional dyes because unlike dyes, they adhere to individual pollen grains, allowing quantitative estimates of pollen movement. In contrast, dye particles are qualitative surrogates for pollen movement. Unlike other pollen‐marking techniques (reviewed by Minnaar and Anderson, 2019), the simple application of quantum dots can be used in most flowers (except plants with very restricted anther openings), they seldom change the transfer characteristics of pollen grains, they can be immediately visualized, and they can be applied in the field.

人类对鲜花有一种奇特的迷恋。从价值数十亿美元的切花产业中繁衍，生长，欣赏，然后扔到克里斯汀·迪奥（Christian Dior）和伊夫·圣洛朗（Yves Saint Laurent）的房子里，那里的花卉提取物使我们闻起来不像哺乳动物，而更像植物，我们对花朵的痴迷使人们很容易忘记它们的进化不是为了迷惑我们，而是主要是为了促进花药从花药到柱头的移动。尽管自达尔文（1862）以来对授粉的研究激增，但花粉运动是授粉的最重要方面之一，仍然是最难量化的活动之一（Minnaar et al。，2019a）。从花药到胚珠的花粉旅程就像一个障碍路线，有障碍，障碍，扭曲和转弯（Inouye等人，1994年）。由于有许多可能的结果，因此很难确定为什么有些花粉颗粒通过了整个过程，而其他花粉颗粒却被阻止或丢失（Minnaar等人，2019a）。但是，如果生物学家可以标记并区分来自不同花朵的外观相同的花粉粒，然后在障碍物路线的不同位置重新捕获这些标记的粒，我们就可以开始追踪导致花粉成功或失败的复杂途径。尽管分子工具可以确定种子的花粉亲本，但难以对花粉进行测序（但请参见Matsuki等，2007），并在许多花粉上施加标签，这意味着大多数花粉粒的命运（其中> 98％的种子无法受精）种子； Harder和Thomson，1989年）仍然神秘。

两项突破为我们提供了跟踪谷物的新工具。首先是确定单个花粉粒基因型的能力（Matsuki等，2007； Hasegawa等，2015）。第二是量子点纳米技术作为荧光花粉标记的应用（Minnaar和Anderson，2019）。量子点（Q点）是半导体金属的晶体，非常小（在人发的整个宽度上有10,000个Q点），它们的行为有点像原子（Gammon，2000年）。当暴露于紫外线下时，它们的电子会在状态之间激发跃迁，发出超明亮的光子（Ekimov，1991）。通过微调Q点的大小，可以改变发射光的颜色（Yoffe，2001年）。）。然后，只需将它们悬浮在溶液中，然后使用移液器将其施加到花药上，即可将覆盖有脂肪酸涂层的Q点附着到花粉颗粒上。然后，在将其沉积在柱头或授粉媒介上后，可使用UV照明来区分以不同颜色标记的花粉粒（图1）。Q点相对于传统染料具有优势，因为与染料不同，它们附着在单个花粉颗粒上，可以定量估计花粉的运动。相反，染料颗粒是花粉运动的定性替代物。与其他花粉标记技术不同（Minnaar和Anderson审查，2019年），量子点的简单应用可以用于大多数花朵（除了具有非常有限的花药开口的植物之外），它们很少改变花粉粒的传递特性，可以立即将其可视化，并且可以在野外应用。