Guedira Mohammed, Paulsen Gary M
Department of Agronomy, Throckmorton Hall, Kansas State University, Manhattan, KS 66506, USA.
Department of Agronomy, Throckmorton Hall, Kansas State University, Manhattan, KS 66506, USA.Corresponding author; email:
Funct Plant Biol. 2002 Apr;29(4):495-503. doi: 10.1071/PP01006.
The impact of high temperatures on accumulation of starch in the grain of wheat (Triticum aestivum L.) is usually attributed to direct effects of the stress on the enzymes involved. However, roots are extremely sensitive to temperatures that can be as high as those experienced by the shoots, and their role in whole-plant responses should be considered. Wheat (cv. Len) was grown at 15/15, 30/15, 15/30, and 30/30˚C shoot/root temperatures during maturation, and accumulation of dry matter and N, contents of sucrose and starch, and activities of enzymes in the pathway of starch assimilation in the endosperm, were measured weekly. Dry matter and N accumulation were affected more by root than by shoot temperatures. High whole-plant temperatures (30/30˚C) accelerated linear grain growth but diminished the duration of assimilation, the contents of sucrose and starch, and the activities of the enzymes involved. The effects of high root temperature (15/30˚C) resembled those of high whole-plant temperature, whereas low root temperature (30/15˚C) tended to ameliorate them. Sucrose synthase and soluble starch synthase were affected more than the other enzymes by high shoot and/or root temperature. However, treatments that caused the lowest activities resulted in the fastest, but briefest, linear rates of grain growth. We concluded that shoots and roots interact in the response of wheat to high temperature, and that stress on both organs affects accumulation of starch in grain.
高温对小麦（Triticum aestivum L.）籽粒中淀粉积累的影响通常归因于该胁迫对相关酶的直接作用。然而，根系对与地上部所经历的温度一样高的温度极为敏感，应考虑其在整株植物响应中的作用。在成熟期间，将小麦（品种Len）种植在15/15、30/15、15/30和30/30˚C的地上部/根系温度条件下，每周测定干物质和氮的积累、蔗糖和淀粉含量以及胚乳中淀粉同化途径中酶的活性。干物质和氮的积累受根系温度的影响大于地上部温度。较高的整株植物温度（30/30˚C）加速了籽粒的线性生长，但缩短了同化持续时间、蔗糖和淀粉含量以及相关酶的活性。高根系温度（15/30˚C）的影响与高整株植物温度的影响相似，而低根系温度（30/15˚C）则倾向于缓解这些影响。高地上部和/或根系温度对蔗糖合酶和可溶性淀粉合酶的影响大于其他酶。然而，导致最低活性的处理导致籽粒生长的线性速率最快，但持续时间最短。我们得出结论，地上部和根系在小麦对高温的响应中相互作用，并且对两个器官的胁迫都会影响籽粒中淀粉的积累。
