Acta Agrestia Sinica ›› 2014, Vol. 22 ›› Issue (3): 550-555.DOI: 10.11733/j.issn.1007-0435.2014.03.017

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The Effects of Drought and Heat Stress on the Photosynthetic Characteristics of Alfalfa

MU Lan, HE Cheng-gang, JIANG Hua, SHAN Gui-lian, WANG Yu-jia, BI Yu-fen   

  1. Department of Animal Science and Technology, Yunnan Agricultural University, Kunming, Yunnan Province 650201, China
  • Received:2013-09-18 Revised:2013-11-18 Online:2014-06-15 Published:2014-06-04

干热胁迫对紫花苜蓿光合特性的影响

牟兰, 何承刚, 姜华, 单贵莲, 王玉佳, 毕玉芬   

  1. 云南农业大学动物科学技术学院, 云南 昆明 650201
  • 通讯作者: 姜华
  • 作者简介:牟兰(1988- ),女,山东高密人,硕士研究生,主要从事牧草品种资源与遗传育种方面的研究,E-mail:mulan1016@163.com;
  • 基金资助:

    国家自然基金项目(31060324)(31160480);云南省自然基金项目(2012FB148)(2008CD031);云南省教育厅重点项目(2012Z021)资助

Abstract:

With the global weather becoming warmer, the drought and heat has become more and more severe. In order to understand the change of photosynthetic characteristics under drought and heat stress, the effects of drought and heat stress on the leaf net photosynthetic rate (Pn), transpiration rate (Tr), intercellular CO2 concentration (Ci), stomatal conductance (Gs), water use efficiency (WUE) of six alfalfa (Medicago sativa L.) cultivars were studied. Results showed that the leaf net photosynthetic rate, transpiration rate, stomatal conductance, water use efficiency of all tested cultivars decreased with the increase of drought and heat stress, while the intercellular CO2 concentration increased (P<0.05). The transpiration rate and stomatal conductance of WL525 recovered obviously after (P<0.05) rehydration, whereas the net photosynthetic rate, intercellular CO2 concentrtion, water use efficiency of all tested cultivars were not improved significantly after rehydration. Correlation analyses showed that the net photosynthetic rate had significantly positive correlation with the transpiration rate, stomatal conductance, water use efficiency of alfalfa under drought and heat stress (P<0.01), but had significantly negative correlation with the intercellular CO2 concentration (P<0.01).

Key words: Alfalfa, Drought and heat stress, Rehydration, Photosynthetic characteristics, Water use efficiency

摘要:

为了解紫花苜蓿(Medicago sativa L.)在干热胁迫条件下光合特性的变化规律,对其6个品种的叶片净光合速率(Pn)、蒸腾速率(Tr)、胞间二氧化碳浓度(Ci)、气孔导度(Gs)、水分利用效率(WUE)进行测定。结果表明,随着干热胁迫强度的增加,各紫花苜蓿品种叶片的净光合速率、蒸腾速率、气孔导度、水分利用效率整体呈下降趋势;而胞间二氧化碳浓度整体呈上升趋势(P<0.05)。且经过一定时间的复水处理,WL525的蒸腾速率和气孔导度得到了明显的恢复(P<0.05),与胁迫前的状态接近,且其他品种的蒸腾速率和气孔导度也得到一定程度的恢复;而供试品种的净光合速率、胞间CO2浓度及水分利用效率均没有得到明显改善。相关分析表明,在干热胁迫条件下,净光合速率与蒸腾速率、气孔导度、水分利用效率均成极显著正相关(P<0.01),而与胞间二氧化碳浓度成极显著负相关(P<0.01)。

关键词: 紫花苜蓿, 干热胁迫, 复水, 光合特性, 水分利用效率

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