[Effects of drought stress on leaf gas exchange and chlorophyll fluorescence of Salvia miltiorrhiza].
Taking the seedlings of Salvia miltiorrhiza cv. Sativa (SA) and S. miltiorrhiza cv. Silcestris (SI) as test materials, this paper studied the effects of drought stress on their leaf gas exchange and chlorophyll fluorescence parameters. After 15 days of drought stress, the net photosynthetic rate (P(n)) and the maximal photochemical efficiency of PS II (F(v)/F(m)) of SA were decreased by 66.42% and 10.98%, whereas those of SI were decreased by 29.32% and 5.47%, respectively, compared with the control, suggesting that drought stress had more obvious effects on the P(n) and F(v)/F(m) of SA than of SI. For SI, the reduction of P, under drought stress was mainly due to stomatal limitation; while for SA, it was mainly due to non-stomatal limitation. Drought led to a decrease of leaf stomatal conductance (G(s)), but induced the increase of water use efficiency (WUE), non-photochemical quenching coefficient (q(N)), and the ratio of photorespiration rate to net photosynthetic rate (P(r)/P(n)), resulting in the enhancement of drought resistance. The increment of WUE, q(N), and P(r)/P(n) was larger for SI than for SA, indicating that SI had a higher drought resistance capacity than SA.
Luo
Ming-Hua
MH
College of Life Science and Biotechnology, Mianyang Normal University, Mianyang 621000, Sichuan, China. mhemei@126.com
Hu
Jin-Yao
JY
Wu
Qing-Gui
QG
Yang
Jing-Tian
JT
Su
Zhi-Xian
ZX
D002245:Carbon Dioxide / Q000378:metabolism*; D055864:Droughts; D010788:Photosynthesis / Q000502:physiology; D045332:Photosystem II Protein Complex / Q000378:metabolism*; D018515:Plant Leaves / Q000378:metabolism / Q000502:physiology; D027561:Salvia miltiorrhiza / Q000502:physiology*; D036226:Seedlings / Q000502:physiology; D013312:Stress, Physiological
D045332:Photosystem II Protein Complex; D002245:Carbon Dioxide