Differences in the stimulation of cyclic electron flow in two tropical ferns under water stress are related to leaf anatomy.
Differences in the stimulation of cyclic electron flow in two tropical ferns under water stress are related to leaf anatomy.
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DOI：
10.1111/j.1399-3054.2012.01657.x
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发表时间：
2013-03
影响因子：
6.4
通讯作者：
Ji‐Hua Wang;Shen-chong Li;Mei Sun;Wei Huang;Hua Cao;Feng Xu;N. Zhou;Shi-Bao Zhang
中科院分区：
文献类型：
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作者：
Ji‐Hua Wang;Shen-chong Li;Mei Sun;Wei Huang;Hua Cao;Feng Xu;N. Zhou;Shi-Bao Zhang
循环电子流（Cyclic electron flow， CEF）在环境胁迫下被子植物的光保护中起着重要作用。然而，由于蕨类植物对干旱更为敏感，其输水系统不如被子植物高效，CEF是否也有助于这些植物的光保护尚不清楚。以斑点微梭菌（Microsorum punctatum）和潜心菌（pareptochillus decurrens）为材料，研究了水分胁迫下它们在光系统I （PSI）和光系统II （PSII）中的电子通量及其叶片解剖结构。我们的目标是确定CEF是否在这些蕨类植物的光保护中起作用，如果有的话，CEF刺激是否与叶片解剖有关。马尾松叶片和角质层较厚，储水能力较强，气孔密度较低，水分流失率较慢。在诱导干旱期间，叶水势（Ψ（叶））的下降在黄杨中比在马尾松中更为明显。对于这两个物种，Ψ（叶）的下降与有效PSII量子产率、PSI光化学量子产率和电子传递率（ETR）的降低有关，而调节能量耗散量子产率、CEF和CEF/ETR（II）比增加有关。光强为500-600µmol m(-2) s（-1）时，斑马草的CEF值和CEF/ETR（II）比值达到峰值，而decurrens的CEF值仅为150-200µmol m(-2) s（-1）。因此，我们的研究结果表明，刺激热带蕨类植物的CEF有助于它们在水分胁迫下的光保护，并且与它们各自的耐旱性和叶片解剖结构有关。
Cyclic electron flow (CEF) plays an important role in photoprotection for angiosperms under environmental stresses. However, ferns are more sensitive to drought and their water transport systems are not as efficient as those of angiosperms, it is unclear whether CEF also contributes to photoprotection in these plants. Using Microsorum punctatum and Paraleptochillus decurrens, we studied the electron fluxes through both photosystem I (PSI) and photosystem II (PSII) under water stress and their leaf anatomies. Our goal was to determine if CEF functions in the photoprotection of these ferns and, if so, whether CEF stimulation is related to leaf anatomy. Compared with P. decurrens, M. punctatum had thicker leaves and cuticles and higher water storage capacity, but lower stomatal density and slower rate of water loss. During induced drought, the decrease in leaf water potential (Ψ(leaf) ) was more pronounced in P. decurrens than in M. punctatum. For both species, the decline in Ψ(leaf) was associated with a lower effective PSII quantum yield, photochemical quantum yield of PSI and electron transport rate (ETR), whereas increases were found in the quantum yield of regulated energy dissipation, CEF and CEF/ETR(II) ratio. Values for CEF and the CEF/ETR(II) ratio peaked in M. punctatum at a light intensity of 500-600 µmol m(-2) s(-1) vs only 150-200 µmol m(-2) s(-1) in P. decurrens. Therefore, our results indicate that the stimulation of CEF in tropical ferns contributes to their photoprotection under water stress, and is related to their respective drought tolerance and leaf anatomy.