[Effects of exogenous nitric oxide on active oxygen metabolism and photosynthetic characteristics of tomato seedlings under cadmium stress].
A hydroponic experiment was conducted to study the effects of exogenous sodium nitroprusside (SNP), a NO donor, on the active oxygen metabolism and photosynthetic characteristics of tomato (Lycopersicon esculentum Mill.) seedlings under Cd stress. The results showed that under the stress, applying 100 micromol x L(-1) SNP promoted the activities of plant superoxide dismutase (SOD) and catalase (CAT) significantly, increased the leaf- and root calcium (Ca) and iron (Fe) contents and the leaf chlorophyll content, net photosynthetic rate (P(n)), transpiration rate (T(r)), and stomatal conductance (G(s)), and decreased the contents of H2O2 and MDA and the concentration of intercellular CO2 (C(i)). The addition of hemoglobin, a NO scavenger, eliminated the effects of SNP, while applying 100 micromol x L(-1) sodium nitrate or nitrite (the decomposition products of NO or its donor SNP) or 100 micromol x L(-1) sodium ferrocyanide (an analog of SNP) had no significant alleviation effects on Cd stress. This study suggested that exogenous NO could promote the scavenging of reactive oxygen, keep the mineral nutrition in balance, and alleviate the damage of Cd stress to the leaf photosynthetic apparatus, making the tomato seedlings preserve their photosynthetic efficiency.
Zhang
Yi-Kai
YK
College of Resources and Environment, Shandong Agricultural University, Taian 271018, Shandong, China. zhang1982@sdau.edu.cn
Cui
Xiu-Min
XM
Yang
Shou-Xiang
SX
Chen
Xiu-Ling
XL
D002104:Cadmium / Q000633:toxicity*; D018551:Solanum lycopersicum / Q000187:drug effects / Q000378:metabolism / Q000502:physiology*; D009569:Nitric Oxide / Q000494:pharmacology*; D010788:Photosynthesis / Q000502:physiology*; D017382:Reactive Oxygen Species / Q000378:metabolism*; D036226:Seedlings / Q000378:metabolism / Q000502:physiology; D013312:Stress, Physiological
D017382:Reactive Oxygen Species; D002104:Cadmium; D009569:Nitric Oxide