School of Environmental and Rural Science, University of New England, Armidale, NSW, 2351, Australia.
Department of Horticulture and Landscape Gardening, Faculty of Agriculture and Plantation Management, Wayamba University of Sri Lanka, Makandura, Gonawila, 60170, North Western Province, Sri Lanka.
Sci Rep. 2022 Feb 25;12(1):3222. doi: 10.1038/s41598-022-06297-2.
Hybrid crop production is more reliant on pollinators compared to open-pollinated crops because they require cross-pollination between a male-fertile and a male-sterile line. Little is known about how stigma receipt of pollen from male-sterile genotypes affects reproduction in hybrids. Non-viable and non-compatible pollen cannot fertilise plant ovules, but may still interfere with pollination success. Here we used seedless watermelon (Citrullus lanatus (Thunb.) Matsum. & Nakai) as a model hybrid plant, to evaluate the morphology, physiology, and movement of pollen from inter-planted genotypes (diploids and triploids). We found that pollen from triploids ('Exclamation' and 'Royal Armada') and diploids ('SP-6', 'Summer Flavor 800', and 'Tiger') was visually distinguishable. Pollen in triploids had more deformities (42.4-46%), tetrads (43-44%), and abnormal growth of callose plugs in pollen tubes. The amount of pollen in triploids to germinate on stigmas was low (8 ± 3%), and few pollen grains produced pollen tubes (6.5 ± 2%). Still, contrary to previous reports our results suggest that some viable pollen grains are produced by triploid watermelons. However, whilst honey bees can collect and deposit pollen from triploids onto stigmas, its effect on hybrid watermelon reproduction is likely to be minimal due to its low germination rate.
与自花授粉作物相比，杂种作物的生产更依赖传粉者，因为它们需要在可育雄株和不育雄株之间进行异花授粉。关于不育基因型的花粉从柱头接收后如何影响杂种的繁殖，人们知之甚少。无活力和不亲和的花粉不能使植物胚珠受精，但仍可能干扰授粉成功。在这里，我们使用无籽西瓜（Citrullus lanatus (Thunb.) Matsum. & Nakai）作为模型杂种植物，评估了来自间作基因型（二倍体和三倍体）的花粉的形态、生理和运动。我们发现三倍体（“惊叹号”和“皇家舰队”）和二倍体（“SP-6”、“Summer Flavor 800”和“Tiger”）的花粉在视觉上是可区分的。三倍体中的花粉有更多的畸形（42.4-46%）、四分体（43-44%）和花粉管中胼胝质塞的异常生长。在柱头萌发的三倍体花粉数量较少（8 ± 3%），产生花粉管的花粉粒较少（6.5 ± 2%）。尽管如此，与之前的报道相反，我们的结果表明，三倍体西瓜确实产生了一些有活力的花粉粒。然而，尽管蜜蜂可以从三倍体上收集和沉积花粉到柱头上，但由于其低发芽率，其对杂种西瓜繁殖的影响可能很小。
