Differences in the stimulation of cyclic electron flow in two tropical ferns under water stress are related to leaf anatomy.

Abstract

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.

• Authors: Ji-Hua Wang, Shen-Chong Li, Mei Sun, Wei Huang, Hua Cao, Feng Xu, Ning-Ning Zhou, Shi-Bao Zhang
• Journal: Physiologia plantarum (Physiol Plant) Vol. 147 Issue 3 Pg. 283-95 (Mar 2013) ISSN: 1399-3054 [Electronic] Denmark
• PMID: 22626455 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: Copyright © Physiologia Plantarum 2012.

Chemical References

• Photosystem I Protein Complex
• Photosystem II Protein Complex
• Water
• Chlorophyll

Topics

• Biological Transport
• Chlorophyll (metabolism)
• Dehydration
• Droughts
• Electron Transport
• Light
• Photosynthesis (physiology)
• Photosystem I Protein Complex (physiology)
• Photosystem II Protein Complex (physiology)
• Plant Epidermis (anatomy & histology, metabolism, physiology, radiation effects)
• Plant Leaves (anatomy & histology, metabolism, physiology, radiation effects)
• Plant Stomata (anatomy & histology, metabolism, physiology, radiation effects)
• Plant Transpiration (physiology)
• Polypodiaceae (anatomy & histology, metabolism, physiology, radiation effects)
• Species Specificity
• Stress, Physiological (physiology)
• Water (metabolism)