| ALA was applied by spraying on tomato (Solanum esculentum L, cv. Jfsg.) cultured under suboptimal temperature or suboptimal photon flux density conditions. The exchange parameters, chlorophyll content, chlorophyll fluorescence parameters, antioxidant enzyme activities and other physiological characterists were determined. The results showed as follows:1. Compared with the treatment of spraying ALA on tomato cultured under appropriate temperature and light conditions, the netphotosynthetic rate (Pn), stomatal conductance (Gs), carboxylation efficiency (CE), apparent quantumyield (AQY), actual photochemical efficiency of PSII (ΦPSII), photochemical quenching (qP), antennatransformation efficiency (Fv′/Fm′), the light compensation point (LCP), CO2 compensation point (CCP) and chlorophyll content of tomato seedlings cultured under suboptimal temperature were decreased, but the intercellular CO2 concentration (Ci) of tomato seedlings were increased.2. Compared with the treatment of spraying water on tomato cultured under suboptimal temperature, the Pn, Gs, CE, AQY,ΦPSII, qP, Fv′/Fm′and chlorophyll content of tomato seedling cultured under suboptimal temperature was increased by the treatment of spraying 30 mg·L-1ALA. On the contrary, the Ci, LCP and CCP were decreased. These results suggested that non-stomatal limitation was the main cause of the decrease of Pn.3. Compared with the treatment of spraying ALA on tomato cultured under appropriate temperature and light conditions, leaf malondialdehyde (MDA) content of tomato cultured under suboptimal temperature was increased, catalase (CAT) activity was decreased and superoxide dismutase (SOD) activity and peroxidase (POD) activity were decreased after an initial increase. Compared with the treatment of spraying water, the Pn, Gs,ΦPSII, Fv/Fm, as well as the activities of SOD, POD and CAT were increased by pretreatment of foliar spraying 30 mg·L-1 ALA, but the Ci and MDA content were decreased by the pretreatment.4. The photon flux density was reduced from 952μmol·m-2·s-1 to 263μmol·m-2·s-1 by 60% shaded treatement in summer and the photon flux density was reduced to 194μmol·m-2·s-1 by 80% shaded treatement. The net photosynthetic rate (Pn), stomatal conductance (Gs), carboxylation efficiency (CE), apparent quantumyield (AQY), the light compensation point (LCP), photochemical quenching (qP), yield and plant height of tomato were decreased by shaded treatment, but the intercellular CO2 concentration (Ci) and CO2compensation point (CCP), chlorophyll content, maximal photochemical efficiency (Fv/Fm), transformation efficiency (Fv′/Fm′), actual photochemical efficiency of PSII (ΦPSII) and plant stem of tomato were increased.5.The decrease amplitude of Pn, Gs, CE, AQY, LCP, qP and yield and the increase amplitude of Ci, CCP,ΦPSII, Fv′/Fm′and Fv/Fm were alleviated by the treatment of spraying 0.06 g·m-2 ALA. Chlorophyll content was increased by the treatment also. But there were no effect were obsevered on plant height and plant stem. Consider comprehensively, the alleviated effect of the treatment of foliar spraying 30 mg·L-1 ALA on tomato cultured under 60% shaded conditions was the best.
|
PDF Full Text Request