不同成熟期对花椰菜种子活力及相关生理生化指标的影响

Effects of Different Maturity Period on Seed Vigor and Physiological and Biochemical Characteristics of Cauliflower Seeds

花椰菜种子收获时常依据经验进行,易导致采收时期不当,对种子质量造成较大的影响。为研究花椰菜杂交种子成熟期与种子活力的关系,确定适宜的种子收获期,本研究以花椰菜品种瓯松60天为材料,分析了授粉后40、45、50、55、60、65 d不同成熟期种子物理性状、种子活力和抗氧化酶活性等指标变化。结果表明,随着种子成熟期延长,种子含水量、鲜种子千粒重呈降低趋势,种子浸泡液电导率和丙二醛(MDA)含量先降低后趋于稳定,规定水分千粒重、超氧化物歧化酶(SOD)活性、过氧化物酶(POD)活性、发芽率、发芽势、活力指数、苗高、根长先增加后趋于稳定。不同授粉后天数之间比较结果表明,授粉后55、60、65 d,活力指数、苗高和根长差异不显著,但均显著高于50 d;规定水分千粒重、SOD活性、POD活性、MDA含量、电导率在授粉后55 d趋于稳定。回归分析结果表明,活力指数与鲜种子千粒重、种子含水量、MDA含量、电导率显著(P<0.05)或极显著(P<0.01)线性负相关,与SOD和POD活性极显著线性正相关(P<0.01)。活力指数、SOD活性、POD活性、MDA含量、电导率与种子发育天数符合二项式函数变化:y_(活力指数)=-0.131x2+16.957x-344.480,y_(SOD活性)=-0.020x2+2.668x-10.420,y_(POD活性)=-0.112x2+14.417x-368.610,y_(MDA含量)=0.113x2-13.771x+433.780,y_(电导率)=0.088x2-10.319x+338.680,达显著或极显著水平,可用来预测不同发育天数种子的活力、保护酶清除活性氧自由基能力和细胞膜结构的完整性。综上,授粉后55 d,瓯松60天种子已达可采收程度,发芽率98%,规定水分千粒重4.364 g,种子活力和种子生理也趋于稳定,且对幼苗生长没有影响,还可降低种子易落粒损失风险。本研究结果为花椰菜杂交种子适时采收提供了理论依据。

The harvest period of cauliflower seed is usually estimated based on experience,which may lead to inappropriate harvesting and adverse seed quality.Studying the relationship between maturity period and seed vigor of cauliflower hybrid seeds can help to determine the optimum harvest period.Hybrid cauliflower Ousong 60 seeds harvested at 40,45,50,55,60 and 65 days after pollination were used to investigate the seed physical properties,seed vigor,and antioxidant enzyme activity,etc.The results showed that,with the increase of maturity,the seed water content and fresh 1000-seeds weight were decreased,electric conductivity of seed soaking solution and MDA content were first decreased and then stabilized,while the specified water 1000-seeds weight,SOD activity,POD activity,germination percentage,germination rate,vigor index,seedling height and root length were increased first and then stabilized.The seed vigor index,seedling height and root length of seeds harvested at 55,60 and 65 days after pollination presented no significant differences,but were all significantly higher than those at 50 days.Specified water 1000-seeds weight,SOD activity,POD activity,MDA content,and electric conductivity,also stabilized after 55 days after pollination.Regression analysis revealed that the vigor index was significantly negatively correlated with fresh 1000-seed weight,seed water content,MDA content and electric conductivity(P<0.05 or P<0.01),while was significantly positively correlated with SOD activity and POD activity(P<0.01).Seed vigor index,SOD activity,POD activity,MDA content and electric conductivity showed binomial relationship with seed development days with significant or extremely significant correlation,y(vigor index)=-0.131x 2+16.957x-344.480,y(SOD activity)=-0.020x 2+2.668x-10.420,y(POD activity)=-0.112x 2+14.417x-368.610,y(MDA content)=0.113x 2-13.771x+433.780,y(electric conductivity)=0.088x 2-10.319x+338.680,which could be used to predict the seed vigor,ability of the enzymes for scavenging reactive oxygen species and the integrity of cell membrane at different maturity stages.In summary,Ousong 60 seeds at 55 days after pollination were ready to harvest with germination percentage of 98%and the specified water 1000-seeds weight of 4.364 g,and the seed vigor and physiology were stabilized,exhibiting no impact on seedling growth and reduced risk of seed loss due to falling.The current study provided theoretical basis for determination of appropriate seed harvesting period of cauliflower hybrid seeds.