[Responses of Rubisco and Rubisco activase in cucumber seedlings to low temperature and weak light].
Using 'Jinyou 3' cucumber seedlings as test materials, this paper studied their photosynthetic rate (P(n)), Ribulose 1,5-bisphosphate carboxylase/oxygenase (Rubisco) and Rubisco activase (RCA) activities, and gene expression of Rubisco and RCA under optimal temperature and weak light (WL: 25 degrees C/18 degrees C, 100 micromol x m(-2) x s(-1)), suboptimal temperature and weak light (ST+WL: 18 degrees C/12 degrees C, 100 micromol x m(-2) x s(-1)), and low temperature and weak light (LT+WL: 10 degress C/5 degrees C, 100 micromol x m(-2) x s(-1)). Comparing with the control (25 degrees C/18 degrees C, 400 micromol x m(-2) x s(-1)), treatments WL, ST+WL, and LT+WL all led to a remarkable decrease in leaf area and dry matter mass. At initial stage, the P(n), Rubisco activity, rbcL and rbcS expression, RCA activity, and CsRCA expression in the three treatments declined by a big margin; 5-7 days later, these parameters tended to be less changed in treatment WL, ascended slowly in treatment ST+WL, and decreased continuously in treatment LT+WL. These results suggested that the photosynthetic apparatus of test cucumber seedlings could gradually adapt to weak light or suboptimal temperature and weak light. The Rubisco and RCA activities and the gene expression of Rubisco and RCA showed the similar responses to low temperature and weak light as the P(n), suggesting that the decline in Rubisco and RCA activities and gene expression in cucumber seedlings under low temperature and weak light could be the important reason leading to the decrease of P(n).
State Key Laboratory of Crop Biology/Ministry of Agriculture Key Laboratory of Horticultural Crop Biology, College of Horticulture Science and Engineering, Shandong Agricultural University, Tai'an 271018, Shandong, China. jzssdau@163.com
Zhen-Sheng
ZS
Jiang
Xiao-Qi
XQ
Sun
Xi-Zhen
XZ
Ai
Mei-Ling
ML
Wang
Huan-Gai
HG
Bi
Hong-Tao
HT
Wang
D003080:Cold Temperature; D018553:Cucumis sativus / Q000201:enzymology* / Q000254:growth & development; D015870:Gene Expression; D008027:Light; D010788:Photosynthesis / Q000502:physiology; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D012273:Ribulose-Bisphosphate Carboxylase / Q000235:genetics / Q000378:metabolism*; D036226:Seedlings / Q000201:enzymology* / Q000254:growth & development
D010940:Plant Proteins; C054765:rca protein, plant; D012273:Ribulose-Bisphosphate Carboxylase