贮藏条件对菘蓝种子萌发和幼苗生理特性的影响

【目的】明确贮藏条件对菘蓝种子萌发和幼苗生理特性的影响,掌握贮藏期间萌发能力与生理特性的变化规律,为菘蓝种子的科学贮藏及高效利用提供参考依据。【方法】以贮藏前种子为对照(CK),设4种贮藏条件:C为自然常温干藏(20~25℃)、CG为自然常温硅胶混合贮藏(20~25℃)、D为低温贮藏(0~4℃)、DG为低温硅胶混合贮藏(0~4℃),分别在贮藏的第0、90、180和270 d时取样,测定种子的发芽率、发芽势和发芽指数,以及幼苗中渗透调节能力、酶促抗氧化系统酶活力和丙二醛(MDA)等指标,并进行各测定指标间的相关分析。【结果】随着贮藏时间的延长,菘蓝种子的发芽率、发芽势和发芽指数均下降,至贮藏结束,C、CG、D和DG条件下的种子发芽率较CK分别显著下降26.50%、14.53%、31.63%和27.35%(P<0.05,下同),发芽势分别下降14.28%、3.06%、22.44%和23.47%,发芽指数分别显著下降32.31%、23.28%、38.90%和45.33%,且CG条件下各指标明显高于其他贮藏条件。此时,酶促抗氧化系统逐渐失去活性,超氧化物歧化酶(SOD)活性逐渐下降,过氧化物酶(POD)和过氧化氢酶(CAT)活性先升后降,而MDA含量在初期下降较明显、后期下降趋于平缓,可溶性糖含量表现出先降后升的变化趋势,可溶性蛋白含量则呈现一直下降趋势。相关分析结果表明,种子萌发特性与幼苗的抗氧化酶系统和贮藏物质呈正相关,但与MDA含量无显著相关性(P>0.05);在整个贮藏期,种子的萌发指标与SOD和CAT活性变化的相关性更高。【结论】菘蓝种子适宜贮藏的条件为20~25℃下与硅胶1∶1混合,SOD和CAT活性可反映出菘蓝种子的活力状况,适用于菘蓝种子活力水平的判断。

Effects of storage conditions on seed germination and seedling physiological characteristics of Isatis indigotica Fort.

【Objective】To investigate the effects of storage conditions on seed germination and seedling physiological characteristics of Isatis indigotica Fort,and to investigatehe changes of germination capacity and physiological characteristics during storage were investigated to provide theoretical and technical basis for scientific storage and efficient utilization of I. indigotica seeds.【Method】The seeds before storage as control(CK),designed with four storage conditions:C was natural dry storage at room temperature(20-25 ℃),CG was natural normal temperature storage(20-25 ℃)with silica gel,D was low temperature storage(0-4 ℃)and DG was low temperature storage(0-4 ℃)with silica gel. Sample seeds for analyses were taken after 0,90,180 and 270 days of storage. to determine the germination rate,germination vigor and germination index of seed. Seedlings were grown from the stored seed samples and their capacity for osmotic regulation,their enzyme activities of the enzymatic antioxidant system,malondialdehyde(MDA)content and other indicators measured. The correlations between these measured indicators were determined and analyzed.【Result】The germination rate,germination vigor and germination index of I. indigotica seeds decreased with the extension of storage time. By the end of stora-ge,the percentage germination rate of C,CG,D,and DG significantly decreased by 26.50%,14.53%,31.63%,and27.35%,respectively,compared with CK(P<0.05,the same below). The germination vigor decreased by 14.28%,3.06%,22.44%,and 23.47%,respectively. The germination index also significantly decreased by 32.31%,23.28%,38.90%,and45.33%,respectively. The indexes under the CG condition were higher than under the other storage conditions. The enzymatic antioxidant system gradually lost its activity,which was manifested as a gradual decrease in SOD,an initial rise then fall in POD and CAT,with a significant decrease in MDA in the early stage,followed by a gentle decrease in the later stages. Soluble sugar content appeared to decrease first and then increase,while soluble protein consistently decreased. Correlation analysis results showed that germination characteristics of seeds were positively correlated with the antioxidant enzyme system and storage substances of seedling,but had no significant correlation with MDA content(P>0.05). During the whole storage period,the correlation between seed germination and SOD and CAT activities was the highest.【Conclusion】The most suitable storage condition for I. indigotica seeds is 1∶1 mixed with silica gel at 20-25 ℃. The activities of SOD and CAT can be used as an relaiable indicator of the vitality of I. indigotica seeds.