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- Title
Photosynthetic response to precipitation/rainfall in predominant tree (Ulmus pumila) seedlings in Hunshandak Sandland, China.
- Authors
Y.-G. Li; G.-M. Jiang; M.-Z. Liu; S.-L. Niu; L.-M. Gao; X.-C. Cao
- Abstract
Abstract??The responses of gas exchange and chlorophyll fluorescence of field-growingUlmus pumilaseedlings to changes in simulated precipitation were studied in Hunshandak Sandland, China. Leaf water potential (?wp), net photosynthetic rate (PN), stomatal conductance (gs), and transpiration rate (E) were significantly increased with enhancement of precipitation from 0 to 20 mm (p<0.01), indicating stomatal limitation ofU. pumilaseedlings that could be avoided when soil water was abundant. However,PNchanged slightly when precipitation exceeded 20 mm (p>0.05), indicating more precipitation than 20 mm had no significant effects on photosynthesis. Maximum photochemical efficiency of photosystem 2, PS 2 (Fv/Fm) increased from 0.53 to 0.78 when rainfall increased from 0 to 10 mm, and Fv/Fmmaintained a steady state level when rainfall was more than 10 mm. Water use efficiency (WUE) decreased significantly (from 78?95 to 23?27 ?mol mol?1) with enhancement of rainfalls.PNshowed significant linear correlations with bothgsand ?wp(p<0.0001), which implied that leaf water status influenced gas exchange ofU. pumilaseedlings. The 20-mm precipitation (soil water content at about 15 %, v/v) might be enough for the growth of elm seedlings. When soil water content (SWC) reached 10 %, down regulation of PS2 photochemical efficiency could be avoided, but stomatal limitation to photosynthesis remained. When SWC exceeded 15 %, stomatal limitation to photosynthesis could be avoided, indicating elm seedlings might tolerate moderate drought.
- Subjects
PLANT photorespiration; ULMACEAE; CHLOROPLAST pigments; WATER use
- Publication
Photosynthetica, 2007, Vol 45, Issue 1, p133
- ISSN
0300-3604
- Publication type
Article
- DOI
10.1007/s11099-007-0021-5