棉花种子活力与其植株停留期间气象因子的关系研究

Relationship between cotton seeds vigor and meteorological factor during plant residence

【目的】探讨种子植株停留期间的气象条件对棉花种子活力的影响。【方法】本试验选择辽棉31和辽棉25两个棉花品种,利用开花当日挂花的方法,获得不同成熟度的棉花种子群体。通过研究比较群体中各样本的百粒重、7 d发芽率、主要营养成分含量以及发芽期间丙二醛(Malondialdehyde, MDA)浓度及过氧化物酶(Peroxidase, POD)、过氧化氢酶(Catalase, CAT)、超氧化物歧化酶(Superoxide dismutase, SOD)活性。【结果】棉花种子的百粒重与植株停留时间显著相关,与开花时间关系不大。辽棉31种子的粗脂肪含量显著高于辽棉25。两个品种间可溶性糖含量和淀粉含量差异不显著,且可溶性糖含量与种子的植株停留时间显著相关。种子发芽期间MDA浓度呈先升高后下降趋势,辽棉25的MDA浓度稍低于辽棉31,但两个品种间差异不显著。种子发芽期间POD活性呈先升高后下降趋势,下降较明显;CAT活性呈先下降再升高趋势,下降明显,但升高有限;SOD活性呈逐渐下降趋势,下降明显。辽棉25种子中上述3种酶的活性都稍高于辽棉31,但差异不显著。通过气象因子与种子生理生化指标的相关分析,发现降水量、≥12℃积温、日温差和日照时间等4个气象因子与种子的百粒重、可溶性糖含量、MDA浓度以及CAT活性等4个特征指标显著或极显著相关。以4个气象因子为自变量、4个种子特征指标为因变量,利用逐步回归的方法获得了25个模拟模型,对其中13个模型利用边缘分析的方法,得出4个气象因子的边际效应。【结论】种子植株停留期间的降水量、≥12℃积温、日温差和日照时间4个气象因子通过影响种子的百粒重、可溶性糖含量、MDA浓度以及CAT活性4个特征指标,进而影响到种子的总体活力,其中日温差和日照时间对种子特征指标的影响较大。辽河流域棉区棉花种子的植株停留时间以65~70 d为宜,这部分种子主要来自早伏桃及部分伏前桃。

[Objective]This study aims to determine the effect of meteorological conditions on cottonseed vigor.[Method]Two cotton varieties,Liaomian 31 and Liaomian 25 were selected.Flowers were hanged on the day of flowering,and the population of seeds with different plant resident time was obtained.The 100-seed weight,7 d germination rate,and main nutrient content of the seeds were measured.Malondialdehyde(MDA)concentration,peroxidase(POD)activity,catalase(CAT)activity,and superoxide dismutase(SOD)activity during germination were also measured.[Result]The 100-seed weight was related to seed residence time in plant but not to with flowering time.The crude fat content in Liaomian 31 seeds was significantly higher than that in Liaomian 25 seeds.The contents of soluble sugars and starch were not significantly different between the two cultivars,and the contents of soluble sugars were related to seed residence time in the plant.During germination,the MDA concentration increased first and then decreased,and was lower in Liaomian 25 than that in Liaomian 31 without significantdifference.The POD activity increased first and then decreased obviously.The CAT activity decreased first obviously and then increased limitedly.The SOD activity decreased continuously and obviously.The activities of POD,CAT,and SOD in Liaomian25 were higher than those in Liaomian 31 without significant difference.The correlation analysis between meteorological factors and seed physiological and biochemical indices indicated that 4 meteorological factors,namely,precipitation,the accumulated temperature of≥12℃,diurnal range,and sunshine hours,exhibited significant or extreme significant correlation with 100-seed weight,soluble sugar content,MDA concentration,and CAT activity during seed germination.Twenty-five simulation models were obtained by stepwise regression method with the four meteorological factors as independent variables and the four seed characteristic indices as dependent variables.Among these models,13 quadratic polynomial models were further analyzed by edge analysis to determine the marginal effects of meteorological factors.[Conclusion]Overall,four meteorological factors,precipitation,the accumulated temperature of≥12℃,diurnal range and sunshine hours during seed resident in plants affected the four seed characteristic indices,100-seed weight,soluble sugar content,MDA concentration,CAT activity,and consequently influenced seed vigor.Among them,the influence of diurnal range and sunshine hours on seed characteristic index is greater.The optimal plant resident time of cotton seeds in the Liaohe River Basin was 65-70 d.These bolls are mainly formed in the middle of July.