Photosynthetic responses of three C4 grasses of different metabolic subtypes to water deficit
Photosynthetic responses of three C4 grasses of different metabolic subtypes to water deficit
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DOI：
10.1071/fp06278
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发表时间：
2007-01-01
影响因子：
3
通讯作者：
Arrabaca, Maria Celeste
中科院分区：
文献类型：
--
作者：
Carmo-Silva, Ana E.;Soares, Ana S.;Arrabaca, Maria Celeste
由于其二氧化碳浓缩机制，C-4 植物被认为比 C-3 植物对干旱不太敏感。比较了 C-4 草雀稗 (NADP-ME)、狗牙根 (L.) Pers (NAD-ME) 和结缕草 (PEPCK) 对在其生长的营养液中添加聚乙二醇所造成的水分亏缺的反应。研究了干旱对叶片相对含水量（RWC）、净光合作用、气孔导度、羧化酶活性和叶绿素a荧光的影响。与 P. dilatatum 和 Z. japonica 相比，C. dactylon 的 RWC 对水分亏缺更敏感，但光合作用活性不太敏感。缺水条件下P. dilatatum光合作用的降低与羧化酶的活性或叶绿素a荧光没有密切关系。然而，核酮糖1,5-二磷酸羧化酶/加氧酶和磷酸烯醇丙酮酸羧化酶的活性降低，除了气孔导度降低之外，可能是导致牵牛花和粳稻光合作用因干旱而降低的原因。结合 C-4 草的自然栖息地讨论了对缺水的不同反应。
C-4 plants are considered to be less sensitive to drought than C-3 plants because of their CO2 concentrating mechanism. The C-4 grasses, Paspalum dilatatum Poiret (NADP-ME), Cynodon dactylon (L.) Pers (NAD-ME) and Zoysia japonica Steudel (PEPCK) were compared in their response to water deficit imposed by the addition of polyethylene glycol to the nutrient solution in which they were grown. The effects of drought on leaf relative water content (RWC), net photosynthesis, stomatal conductance, carboxylating enzyme activities and chlorophyll a fluorescence were investigated. In C. dactylon the RWC was more sensitive, but the photosynthetic activity was less sensitive, to water deficit than in P. dilatatum and Z. japonica. The decrease of photosynthesis in P. dilatatum under water deficit was not closely related to the activities of the carboxylating enzymes or to chlorophyll a fluorescence. However, decreased activities of ribulose 1,5-bisphosphate carboxylase/oxygenase and phosphoenolpyruvate carboxylase, in addition to decreased stomatal conductance, may have contributed to the decrease of photosynthesis with drought in C. dactylon and Z. japonica. The different responses to water deficit are discussed in relation to the natural habitats of C-4 grasses.