基于PEG-6000模拟干旱胁迫下三个甘蔗品种种茎根芽萌发特征

Stem Bud and Root Germination Characteristics of Three Sugarcane Varieties Simulated Under Drought Stress Based on PEG-6000

为探究三个抗旱性不同的甘蔗品种[‘中蔗9号’(ZZ9),抗旱性强;‘中蔗2号’(ZZ2),抗旱性弱;‘新台糖22号’(Xintaitang22),抗旱性居中]在不同干旱胁迫环境下萌发早期种茎根和芽萌发的差异,试验采用水培法用不同浓度梯度PEG-6000[CK、10%(w/v)和20%(w/v)]模拟干旱胁迫连续培养12 d后采集根系和芽的萌发数量、根和芽的生物量、根系的形态特征及生理指标数据。研究结果显示,抗旱性强的品种‘中蔗9号’根系的形态指标(根总长、根面积、根体积和根直径等)均显著高于‘中蔗2号’和‘新台糖22号’的。随着PEG-6000胁迫程度加深,‘中蔗2号’的根系脱落率显著高于‘中蔗9号’的,在高浓度PEG-6000(20%)胁迫下,随时间的延长‘中蔗2号’的根系数量急剧下降,而‘中蔗9号’的根系数量呈现上升趋势,说明‘中蔗9号’的根点在高浓度PEG-6000模拟干旱胁迫下仍能保持生活力,并从休眠状态复苏而继续萌发。‘中蔗9号’的根茎粗壮,根系生物量最多,芽体生物量最少,而‘中蔗2号’反之,根系生物量最少,芽体生物量最多。在高浓度PEG-6000胁迫下,‘中蔗2号’和‘新台糖22号’的SOD、POD的酶活性均下降,而‘中蔗9号’的处于持续上升趋势,此时‘中蔗9号’根系的脯氨酸含量亦极显著(240%)上升。在PEG-6000模拟干旱胁迫下,甘蔗种茎根芽萌发的上述特征与大田抗旱表型观察结果相吻合。本研究结果为快速筛选抗旱甘蔗品种提供了参考依据。

The aim of this study was to investigate the difference of stem root and bud germination of three sugarcane varieties with different drought resistance['Zhongzhe9'(ZZ9),drought resistance is strong;'Zhongzhe2'(ZZ2),drought resistance is weak;'Xintaitang22'(Xintaitang22),drought resistance is medium]under different drought stress conditions in early germination.In the experiment,hydroponics was used to simulate drought stress with PEG-6000[CK,10%(w/v)and 20%(w/v)]for 12 consecutive days,and the germination quantity of roots and buds,the biomass of roots and buds,the morphological characteristics and physiological indexes of roots were collected.The results showed that the root morphological indexes(total root length,root area,root volume and root diameter,etc.)of'Zhongzhe9'with strong drought resistance were significantly higher than those of'Zhongzhe2'and'Xintaitang22'.With the deepening of PEG-6000 stress,the root shedding rate of'Zhongzhe2'was significantly higher than that of'Zhongzhe9'.Under high concentration of PEG-6000(20%)stress,the root number of'Zhongzhe2'decreased sharply with the extension of time,while the root number of'Zhongzhe9'showed an increasing trend.The results showed that'Zhongzhe9'could maintain vitality and recover from dormancy state under simulated drought stress with high concentration of PEG-6000.'Zhongzhe9'had the largest rhizome biomass and the smallest sprout biomass,whereas'Zhongzhe2'had the smallest root biomass and the largest sprout biomass.Germination and growth of buds need more water and nutrients,which undoubtedly increases the burden of water absorption of roots in the early stage of germination,which should not be an advantage for drought resistance of plants,which may be one of the reasons why'Zhongzhe9'has strong drought resistance and'Zhongzhe2'has weak drought resistance.Under high concentration PEG-6000,SOD and POD activities of'Zhongzhe2'and'Xintaitang22'decreased,while'Zhongzhe9'showed a continuous upward trend,and the proline content of roots of'Zhongzhe9'also increased significantly(240%).The above characteristics of sugarcane stem germination under PEG-6000 simulated drought stress were consistent with the observation results of drought-resistant phenotypes in the field.The results of this experiment provided a reference for rapid selection of sugarcane varieties with strong drought resistance.