Photosynthetic responses to heat treatments at different temperatures and following recovery in grapevine (Vitis amurensis L.) leaves. 2011 PLoS One, 6: e23033

Hai-Bo Luo1,2, Ling Ma1,2, Hui-Feng Xi1,2, Wei Duan1, Shao-Hua Li3, Wayne Loescher4, Jun-Fang Wang1,2, Li-Jun Wang1*

1 Beijing Key Laboratory of Viticulture and Enology, and Key Laboratory of Plant Resource Science, Institute of Botany, Chinese Academy of Sciences, Beijing, People‘s Republic of China, 2 Graduate University of Chinese Academy of Sciences, Beijing, People‘s Republic of China, 3 Key Laboratory of Plant Germplasm Enhancement and Speciality Agriculture, Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan, People‘s Republic of China, 4 College of Agriculture and Natural Resources, Michigan State University, East Lansing, Michigan, United States of America

Abstract
Background
The electron transport chain, Rubisco and stomatal conductance are important in photosynthesis. Little is known about their combined responses to heat treatment at different temperatures and following recovery in grapevines (Vitis spp.) which are often grown in climates with high temperatures.
Methodology/Findings
The electron transport function of photosystem II, the activation state of Rubisco and the influence of stomatal behavior were investigated in grapevine leaves during heat treatments and following recovery. High temperature treatments included 35, 40 and 45°C, with 25°C as the control and recovery temperature. Heat treatment at 35°C did not significantly (P>0.05) inhibit net photosynthetic rate (Pn). However, with treatments at 40 and 45°C, Pn was decreased, accompanied by an increase in substomatal CO2 concentration (Ci), decreases in stomatal conductance (gs) and the activation state of Rubisco, and inhibition of the donor side and the reaction center of PSII. The acceptor side of PSII was inhibited at 45°C but not at 40°C. When grape leaves recovered following heat treatment, Pn, gs and the activation state of Rubisco also increased, and the donor side and the reaction center of PSII recovered. The increase in Pn during the recovery period following the second 45°C stress was slower than that following the 40°C stress, and these increases corresponded to the donor side of PSII and the activation state of Rubisco.
Conclusions
Heat treatment at 35°C did not significantly (P>0.05) influence photosynthesis. The decrease of Pn in grape leaves exposed to more severe heat stress (40 or 45°C) was mainly attributed to three factors: the activation state of Rubisco, the donor side and the reaction center of PSII. However, the increase of Pn in grape leaves following heat stress was also associated with a stomatal response. The acceptor side of PSII in grape leaves was responsive but less sensitive to heat stress.

http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0023033#abstract0