植物生态学报 ›› 2017, Vol. 41 ›› Issue (4): 480-488.doi: 10.17521/cjpe.2016.0210

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接种丛枝菌根真菌对受镉胁迫美洲黑杨雌、雄株光合生理的影响

陈良华, 赖娟, 胡相伟, 杨万勤, 张健*(), 王小军, 谭灵杰   

  1. 四川农业大学生态林业研究所, 长江上游生态安全协同创新中心, 林业生态工程四川省重点实验室, 成都 611130
  • 收稿日期:2016-06-27 接受日期:2016-12-25 出版日期:2017-04-10 发布日期:2017-05-19
  • 通讯作者: 张健 E-mail:sicauzhangjian@163.com
  • 基金资助:
    国家自然科学基金(31300513)

Effects of inoculation with arbuscular mycorrhizal fungi on photosynthetic physiology in females and males of Populus deltoides exposed to cadmium pollution

Liang-Hua CHEN, Juan LAI, Xiang-Wei HU, Wan-Qin YANG, Jian ZHANG*(), Xiao-Jun WANG, Ling-Jie TAN   

  1. Key Laboratory of Ecological Forestry Engineering, Collaborative Innovation Center of Ecological Safety in the Upper Reaches of Yangtze River, Institute of Ecology & Forestry, Sichuan Agricultural University, Chengdu 611130, China
  • Received:2016-06-27 Accepted:2016-12-25 Online:2017-04-10 Published:2017-05-19
  • Contact: Jian ZHANG E-mail:sicauzhangjian@163.com

摘要:

美洲黑杨(Populus deltoides)是长江中下游及江淮平原重要的造林树种, 目前广泛栽培的美洲黑杨既有雄株品系, 也有雌株品系。为了解镉(Cd)胁迫条件下美洲黑杨雌、雄株的耐受性差异, 采用盆栽实验, 研究Cd污染(10 mg·kg-1)条件下美洲黑杨雌、雄株气体交换速率、CO2响应曲线、叶绿素荧光参数、渗透调节能力、激素含量的响应特征, 以及接种丛枝菌根真菌(Rhizophagus intraradices)对受Cd胁迫美洲黑杨雌、雄株的生理效应。结果表明: (1) Cd胁迫下, 美洲黑杨雌、雄株净光合速率、气孔导度、胞间CO2浓度、蒸腾速率、光系统II (PSII)最大光化学量子产量、PSII有效光化学量子产量、光化学淬灭系数、最大羧化速率、最大电子传递速率、磷酸丙糖利用速率均不同程度降低, 雌株的下降幅度更大, 接种丛枝菌根真菌的雌株的以上参数有了不同程度的恢复, 但对雄株没有明显影响; (2) Cd胁迫下, 美洲黑杨雌雄株的脯氨酸含量均显著增加, 接种丛枝菌根真菌进一步提高了雌株的脯氨酸含量; (3) Cd胁迫下, 美洲黑杨雌、雄株叶片生长素含量下降, 脱落酸含量增加, 雌株的变化幅度更大, 接种丛枝菌根真菌有利于恢复雌株激素的平衡。由此可见, 与雄株相比, Cd胁迫对美洲黑杨雌株气体交换速率和碳固定能力的负面影响更大, 植株光合机构受损更严重, 激素平衡更易受到影响, 表现出更弱的胁迫耐受性; 接种丛枝菌根真菌有利于增强美洲黑杨雌株的渗透调节能力并在一定程度上恢复雌株的固碳能力和激素平衡, 但菌根对雄株的效应并不显著。

关键词: 丛枝菌根, 美洲黑杨, 镉污染, 雌雄异株, 光合作用

Abstract:
Aims Populus deltoides is an important plantation tree species in the middle and lower reaches of the Yangtze River and in Huai River Plain. The extensively cultivated varieties are consisted of both females and males of P. deltoides. The objective of this paper was to characterize the difference in cadmium (Cd) tolerance between the sexes and the effects of symbiosis with Rhizophagus intraradices on their Cd tolerance.
Methods The experiment was carried out under semi-controlled conditions in a natural light greenhouse, protected from rain. Rhizophagus intraradices was inoculated on roots of both females and males when transplanting to a sand culture substrate. After one month, half of cuttings were exposed to Cd pollution (10 mg·kg-1). All cuttings were irrigated with sterile water to avoid infection by other microorganism. About three months later, the gas exchange rate, net photosynthesis rate (Pn)-intercellular CO2 concentration (Ci) curve, chlorophyll fluorescence, osmotic adjustment and phytohormone content of both females and males of P. deltoides were measured.
Important findings Our main results are as follows: (1) when compared to the controls, decreases in Pn, stomatal conductance, Ci, transpiration rate, maximum photochemical efficiency of photosystem II (PSII), effective quantum yield of PSII, photo-chemical quenching coefficient, maximum rate of carboxylation of Rubisco, photosynthetically active radiation-saturated rate of electron transport and rate of triose phosphate utilization to a different degree in both sexes of P. deltoides under Cd pollution were found, and females exhibited a greater decrease in such parameters than males. Rhizophagus intraradices inoculation mitigated the toxic effect of Cd on such parameters to a different degree in females, not in males. (2) Under Cd pollution, there was an increase in proline content in both sexes when compared to the controls. A further increase in proline content occurred in females, not in males, when inoculated with R. intraradices. (3) When compared to the controls, there was a decrease in indoleacetic acid, but an increase in abscisic acid in leaves of both sexes when exposed to Cd pollution. The amplitude changed in both phytohormones in females was greater than that in males. Rhizophagus intraradices inoculation was helpful for recovery of phytohormone balance in females, which was not observed in males. Therefore, our results indicated that (1) there were a greater negative effect exerted by Cd pollution on gas exchange rate, carbon fixation capacity and phytohormone balance and a more impairment of photosynthetic apparatus in females when compared to males, showing a less tolerance to stress conditions in females; (2) Rhizophagus intraradices inoculation could enhance the osmotic adjustment capacity in females, thus mitigate the negative effect of Cd stress on ability of carbon fixation and phytohormone balance in females. However, such positive effects derived from R. intraradices symbiosis were not observed in males.

Key words: vesicular-arbuscular mycorrhiza, Populus deltoides, cadmium pollution, dioecy, photosynthesis