外源钙对不同钙敏感型番茄幼苗生理特性的影响

利用钙不敏感型番茄品种（江蔬1号）和钙敏感型番茄品种（L₄₀₂）为试材，研究了不同浓度的外源钙对其根系活力、钙调素含量、叶绿素a、b含量和比值及活性氧清除酶系统活性的影响.结果表明，根系钙调素（CaM）含量随介质钙浓度增加而增加，不敏感品种江蔬1号高于敏感品种L₄₀₂.根系活力、生长点和真叶chla/b比值在低钙强度下（1和4 mg·L^-1）以江蔬1号显著高于L₄₀₂，在充足供钙时（100 mg·L^-1）L₄₀₂显著高于江蔬1号，表明江蔬1号品种具有较强的耐低钙和光胁迫的能力.对活性氧清除酶系统活性来说，在三个钙浓度下敏感品种L₄₀₂的POD、CAT酶活性均显著高于江蔬1号，降钙使两酶活性升高，SOD酶活性下降，且L₄₀₂下降的幅度高于江蔬1号，表明低钙造成的胁迫对L₄₀₂品种影响较大，江蔬1号较耐受缺钙胁迫.

Effects of exogenous Ca on some physiological characteristics of tomato (Lycopersicon esculentum) seedlings with different Ca sensitivity

Two tomato (Lycopersicon esculentum) cultivars with different Ca sensitivity were used to study the effects of exogenous Ca on their root activity, CaM content, chlorophyll a/b ratio, and reactive oxygen-scavenging enzymes' activities under different Ca concentrations in nutrient solution. The results showed that the root activity and CaM content of two cultivars increased with increasing Ca concentrations in the nutrient solution. The root activity and chlorophyll a/b ratio of Ca-insensitive cultivar Jiangshuyihao were higher than those of Ca-sensitive L-402 under extreme low Ca stress (1 and 4 mg x L(-1)), while lower than those of L-402 when sufficient Ca was applied (100 mg x L(-1)), indicating that Jiangshuyihao had a greater capability to bear the nutrient and light stress under low Ca stress. The SOD activity of Ca-insensitive cultivar Jiangshuyihao under 1 and 4 mg x L(-1) Ca was higher than that of L-402, while the activities of POD and CAT of L-402 were consistently higher than that of Jiangshuyihao under test Ca concentrations in the nutrient solution. Comparing with 100 mg x L(-1) Ca in solution, 4 mg x L(-1) Ca led to an increase of CAT and POD activities and a decrease of SOD activity in the two cultivars, but the variation of SOD activity was greater in L-402 than in Jiangshuyihao, indicating that the system of defence enzymes in Ca-insensitive cultivar played a key role when suffered from Ca stress.