1. Effects of high temperature stress on photosynthesis and chlorophyll fluorescence of cut flower chrysanthemum (Dendranthema grandiflora 'Jinba').
- Author
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Xian-zhi Sun, Cheng-shu Zheng, and Xiu-feng Wang
- Abstract
Cut flower chrysanthemum (Dendranthema grandiflora 'Jinba') plants were treated with 40 °C/35 °C or 33 °C/28 °C (day/night) for 11 days and then transferred to 23 °C/18 °C for 5 days to study the changes in their photosysnthesis and flourescence parameters under high temperature stress and normal temperature recovery. The results showed that on the 5
th day of 33 °C/28 °C treatment, net photosynthesis (Pn ) decreased gradually and stomatal conductance (Gs ) decreased evidently; while after recovery for 5 days, both Pn and Gs resumed to 80% of the control. At 40 °C/35 °C, Pn and Gs decreased dramatically. The increase of intercellular CO2 concentration (Ci ) at the early stage under given high temperatures that the photosynthesis inhibition by high temperature stress was resulted from non-stomatal limitations. However, 9 days later, stomatal limitation became the mainly cause of photosynthesis inhibition by high temperature stress was resulted from non-stomatal limitations. However, 9 days later, stomatal limitation became the mainly cause of photosynthesis inhibition. The intrinsic photochemical efficiency (Fv /Fm ), quantum yields of PS II (ΦPS II ), and the efficiency of excitation energy capture by open PS II reaction center (Fv '/Fm ') at 33 °C/28 °C and 40 °C/35 °C all decreased light capture and efficiency of electron transfer through PS II. The photochemical quenching (qp ) at 33 °C/28 °C descended first and turned to rise then, suggesting that the election transfer was firstly restrained by the stress. Contrastively, qp rose continuously at 40 °C/35 °C, indicating that oxygen-evolving complex (OEC) was the location in chrysanthemum photosynthesis apparatus most sensitive to extreme high temperature. [ABSTRACT FROM AUTHOR]- Published
- 2008