Koti S, Reddy K R, Kakani V G, Zhao D, Reddy V R
Department of Plant and Soil Sciences, Box 9555, 117 Dorman Hall, Mississippi State University, Mississippi State, MS 39762, USA.
Ann Bot. 2004 Dec;94(6):855-64. doi: 10.1093/aob/mch212. Epub 2004 Oct 5.
Ultraviolet-B (UV-B) radiation effect on reproductive parts of the plants has received little attention. We studied the influence of UV-B radiation on flower and pollen morphology, pollen production and in vitro pollen germination and tube growth of six genotypes of soybean (Glycine max).
Soybean genotypes were investigated by growing them under four levels of biologically effective UV-B radiation of 0 (control), 5, 10 and 15 kJ m(-2) d(-1) in sunlit controlled-environment chambers.
Reductions in lengths of flower, standard petal, and staminal column along with reduced pollen production, germination and tube growth were observed in all genotypes with increasing UV-B radiation. Combined response index (CRI), the sum of percentage relative responses in flower size, pollen production, pollen germination and tube growth due to UV-B radiation varied with UV-B dosage: -67 to -152 with 5 kJ m(-2) d(-1), -90 to -212 with 10 kJ m(-2) d(-1), and -118 to -248 with 15 kJ m(-2) d(-1) of UV-B compared to controls. Genotypes were classified based on the UV-B sensitivity index (USI) calculated as CRI per unit UV-B, where D 90-9216, DG 5630RR and D 88-5320 were classified as tolerant (USI > -7.43), and DP 4933RR, Stalwart III and PI 471938 were sensitive (USI < -7.43) in their response to UV-B radiation. Pollen grains produced in plants grown at 15 kJ m(-2) d(-1) UV-B radiation were shrivelled and lacked apertures compared to control and other UV-B treatments in both sensitive and tolerant genotypes, and the differences were more conspicuous in the sensitive genotype (PI 471938) than in the tolerant genotype (D 90-9216). The number of columellae heads of the exine was reduced with increasing UV-B radiation.
Soybean genotypes varied in their reproductive response to UV-B radiation. The identified UV-B tolerant genotypes could be used in future breeding programmes.
紫外线B（UV-B）辐射对植物繁殖器官的影响鲜有研究。我们研究了UV-B辐射对6个大豆（Glycine max）基因型的花朵和花粉形态、花粉产量以及体外花粉萌发和花粉管生长的影响。
将大豆基因型种植在阳光充足的可控环境培养箱中，设置4个生物有效UV-B辐射水平，分别为0（对照）、5、10和15 kJ m(-2) d(-1)，以此对其进行研究。
随着UV-B辐射增加，所有基因型均出现花朵、旗瓣和雄蕊柱长度缩短，以及花粉产量、萌发率和花粉管生长降低的情况。综合响应指数（CRI），即因UV-B辐射导致的花朵大小、花粉产量、花粉萌发和花粉管生长的相对响应百分比之和，随UV-B剂量变化：与对照相比，UV-B剂量为5 kJ m(-2) d(-1)时，CRI为-67至-152；10 kJ m(-2) d(-1)时，为-90至-212；15 kJ m(-2) d(-1)时，为-118至-248。根据以每单位UV-B的CRI计算的UV-B敏感性指数（USI）对基因型进行分类，其中D 90-9216、DG 5630RR和D 88-5320被分类为耐受性基因型（USI > -7.43），而DP 4933RR、Stalwart III和PI 471938对UV-B辐射敏感（USI < -7.43）。与对照及其他UV-B处理相比，在15 kJ m(-2) d(-1) UV-B辐射下生长的植物所产生的花粉粒，在敏感和耐受性基因型中均出现干瘪且无萌发孔的情况，且在敏感基因型（PI 471938）中差异比耐受性基因型（D 90-9216）中更明显。随着UV-B辐射增加，花粉外壁小柱头部数量减少。
大豆基因型对UV-B辐射的繁殖响应存在差异。所鉴定出的UV-B耐受性基因型可用于未来的育种计划。
