《植物生理学报》 2017, 53(5): 795-806
通信作者：王文泉；E-mail: wangwenquan@itbb.org.cn
摘 要：
以木薯耐旱品种SC124与不耐旱品种Arg7为材料, 在成株期持续干旱胁迫26 d, 分析此过程中植株茎杆皮层、中柱可溶性糖、淀粉含量及糖代谢相关酶的活性变化。结果表明: 干旱胁迫下2个品种茎杆皮层和中柱均产生较高浓度的海藻糖, 而对照无海藻糖, 海藻糖是木薯适应干旱渗透调节的重要物质; 一定程度干旱胁迫下, 木薯中柱与皮层果糖与葡萄糖含量升高, 而蔗糖含量上升后又降低, 说明干旱胁迫蔗糖有降解成分子量更小的葡萄糖与果糖的趋势; 而在严重干旱状态下, 可溶性糖的含量大幅度降低, 渗透调节能力降低。干旱胁迫下, 耐旱品种SC124茎杆皮层、中柱中可溶糖含量高于不耐旱品种Arg7。木薯茎杆中含有大量的淀粉, 淀粉含量测定及扫描电镜结果显示, 干旱胁迫下SC124与Arg7皮层与中柱中的淀粉含量均显著降低。干旱胁迫下茎杆中ADPG焦磷酸化酶(AGPase)、淀粉磷酸化酶(SP)、α-淀粉酶及蔗糖合成酶(SuSy)活性的测定也证明了淀粉分解类酶活性增加。关键词：木薯; 干旱胁迫; 茎杆; 可溶性糖; 淀粉; 酶活
收稿：2017-04-05 修定：2017-05-12
资助：国家木薯产业技术体系(CARS-12wwq)和海南大学科研启动基金(kyqd1426)。
Corresponding author: WANG Wen-Quan; E-mail: wangwenquan@itbb.org.cn
Abstract:
This study examined the active changes of the soluble sugar content, starch content and enzyme activities in cortex and stele of plant stem after continuous drought for 26 days. Two cassava varieties, SC124 (drought resistant) and Arg7 (sensitive to water stress), were used for investigating the drought response of starch metabolism. The results showed that trehalose with a higher concentration produced in the cortex and stele of stems in both SC124 and Arg7 under the drought stress, which was an important component of osmotic regulation in cassava adaptable to water stress. Also, fructose, glucose and sucrose were important osmotic materials in cassava. Fructose and glucose contents of the cortex and stele increased, while sucrose contents increased and then decreased. The results indicated that sucrose was degradated into glucose and fructose under drought stress, which were smaller molecular weight. While the content of soluble sugar decreased greatly, and the capacity of osmotic regulation decreased under severe drought conditions. Drought-resistant variety SC124 had higher soluble sugar content in the cortex and stele than non-drought-resistant variety Arg7 under drought stress. The analysis of starch contents, and examination of the number of starch grains with scanning electron microscope showed that SC124 and Arg7 contained a lot of starch in stem, while decreased significantly in the cortex and stele under drought stress. Moreover, the activity of ADP-glucose pyrophosphorylase (AGPase), starch phosphorylase (SP), α-amylase and sucrose synthase (SuSy) in stem were measured to indicate that the activity of starch decomposition enzyme increased under drought stress.Key words: cassava (Manihot esculenta Crantz); drought stress; stem; soluble sugars; starch; enzyme activity
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