PEG胁迫对木薯叶片形态、生理及根系解剖结构的影响

为探讨木薯的干旱响应,采用0(CK)、10%、20%、30%PEG模拟法,研究干旱对木薯叶片形态、生理,以及根系解剖结构等的影响。结果表明,与CK相比,在30%PEG处理下,木薯叶片均萎蔫、下垂。除SC205游离脯氨酸含量在30%PEG处理下降外,3份种质叶片的O2-产生速率、游离脯氨酸含量均随PEG浓度提高而明显提高。在PEG胁迫下,Rayong9叶片的可溶性蛋白含量无明显变化,CMR35-22-196的显著提高,SC205的明显降低。3份种质在20%PEG和30%PEG处理下,均出现表皮或薄壁细胞残缺、根冠脱落现象;且Rayong9在30%PEG处理下,根系出现细胞程序性死亡,SC205、CMR35-22-196在20%和30%PEG处理下,根系出现细胞程序性死亡、表皮细胞栓化。可见,干旱胁迫对木薯生长不利,胁迫越强,危害越大。

Influence of PEG Stress on the Morphology and Physiology of Leaf and Anatomical Structure of Root of Cassava

The purpose of this study was to investigate the variation of different cassava germplasms responding to drought stress. The leaf morphology, leaf physiology and root anatomical structure of three cassava germplasms, namely Rayong9, SC205 and CMR35-22-196, were evaluated, under drought stress using 0(CK), 10%, 20% and 30% of PEG solutions. The results showed that the leaves of the three germplasms became wilting and drooping at the 30% PEG. The O2- production rate and the free proline contents of the three germplasms increased with the increasing of PEG, except for the free proline content of SC205 decreased at the 30% PEG. When compared with the 0 PEG, PEG stress affected slightly the soluble proteins content of Rayong9, while, those of SC205 and CMR35-22-196 were decreased and increased dramatically, respectively. The epidermis or parenchyma cells of root of the three germplasms, were incomplete and the root cap came off at the 20% and 30% PEG, when compared with the 0 PEG. Simultaneously, the programmed death cells in root were appeared for Rayong9 at the 30% PEG, while, the programmed death cells and suberisated epidermis were both appeared for SC205 and CMR35-22-196 at the 20% and the 30% PEG. In short, drought stress was bad for the growth of cassava, and the damage was getting worse with the aggravating drought stress.