摘要
The Tarim Basin,Xinjiang,China,a region important to the walnut industry,is affected by frequent heavy dust storms.Dust,including micro-particles(diameter<10μm),covers the surface of the walnut tree,thereby changing the surface-atmosphere interface microenvironment,which,in turn,influences the exterior and interior structure of the tree.Dust storms occur in spring and summer,during the flowering period of walnut,which is the key developmental stage leading to fruit formation.This study investigated the effects of dust on female flowers,male flowers,and the pollination of walnut.The morphological changes in the stigma during pollination were recorded.Stigma receptivity was studied via the benzidine–H2O2 method.Morphological features of the female floral organs and pollen were investigated using scanning electron microscopy.Pollen germination and pollen tube growth were examined by fluorescence microscopy.The results showed that dust had a significant inhibitory effect on male and female flowers,resulting in decreased catkin growth,reduced pollen viability(pollen viability was 20.13%),blocked pollen apertures,a reduced pollen germination rate on the stigma,and increased time needed for pollen tube appearance.Dust also had an inhibitory effect on stigma length and receptivity of female walnut flowers,with the length of the walnut stigma being reduced by 0.25~0.80 mm during the flowering process.In addition,there was decreased stigma mucus,resulting in stigma atrophy,decreased amount of pollen on the stigma,weakened stigma receptivity,and accelerated drying of female flowers.In the Tarim Basin,walnut flowering occurd at the same time as dust storms do,which had a negative impact on the floral organ,flowering and pollination of walnut.
塔里木盆地是核桃的主产区,又是沙尘暴源区及频发区;沙尘暴及沙尘暴后所产生的自然降尘(包括直径<10μm的颗粒物)能够在植物表面积累形成覆盖层,改变植物—气界面,影响植物的外部和内部结构。自然降尘多集中在春夏季,这正与核桃的生育期特别是花期相遇,自然降尘对核桃的生殖活动是否会带来不利影响尚不清楚,但相关研究已证明自然降尘会损伤果树叶片表面和内部结构,从而间接影响果树产量及品质。该文应用联苯胺-过氧化氢法研究核桃雌花柱头可授性;扫描电镜观察雌花器官和花粉的形态特征;利用荧光显微镜观察花粉萌发和花粉管生长情况,旨在探讨降尘对核桃雌花、雄花发育及授粉受精的影响。结果表明,降尘对雄花和雌花均有显著的抑制作用,导致花粉生活力下降(花粉生活力为20.13%),花粉孔受阻,花粉萌发率降低,花粉管形成所需时间延长。对核桃雌花柱头长度和可授性也有抑制作用,在开花过程中核桃柱头长度减少了0.25~0.80 mm。此外,柱头粘液减少,导致柱头萎缩,柱头上花粉量减少,柱头可授性减弱,雌花干燥加速。在新疆塔里木盆地,核桃开花期与沙尘暴同时发生,对核桃花器官、授粉和开花都产生了不利影响。
基金
国家自然科学基金(31960325,31760219)
2017年自治区高校科研计划(重大项目)(XJEDU20171006)
天山青年计划(2018Q020)
天山英才计划(第三期)
新疆农业大学博士后流动站.
作者简介
陈虹(1981-),女,四川南充人,副教授,主要从事核桃生理与栽培的研究;通信作者:陈虹。
