茶氨酸对烟草幼苗生长及生理特性的影响

为了研究茶氨酸对烟草幼苗生长及生理特性的影响,以云烟87为材料,进行水培试验,对不同茶氨酸浓度(0、0.5、1和5 mmol·L-1)处理下烟草幼苗的生长特征及部分生化指标进行测定。结果表明,茶氨酸会使烟草幼苗根长变短,地上部分、地下部分干重和鲜重、根冠比以及叶绿素含量明显降低;可溶性蛋白、脯氨酸和还原型谷胱甘肽(GSH)含量升高;超氧化物歧化酶(SOD)、过氧化物酶(POD)活性升高,过氧化氢酶(CAT)活性降低,抗氧化酶系统失衡导致H2O2在烟草幼苗体内累积引起膜脂氧化造成损伤,丙二醛(MDA)含量及相对电导率相应的升高进一步说明了上述结论。由此可见,外源施加茶氨酸会使烟草幼苗体内抗氧化系统失衡致使膜脂氧化引发氧化损伤从而抑制其生长。

Influence of theanine on the growth and physiological indexes of tobacco seedlings

In order to elucidate the influence of theanine on the growth and related physiological indexes of tobacco seedlings, Yunyan 87 was used to study the effects of different concentrations of theanine (0, 0.5, 1 and 5 mmol/L) on the growth characteristics and related physiological indexes of tobacco seedlings under the hydroponic cultivation condition. As results, theanine significantly decreased the root length, root dry and fresh weight, shoot dry and fresh weight, root-shoot ratio, and chlorophyll content; however, it significantly increased the content of soluble protein, proline, and GSH. The increase of SOD and POD activities and the decrease of CAT activity caused the unbalance of antioxidant enzyme systems, which ultimately led to the accumulation of H₂O₂ in tobacco seedlings, causeing lipid membrane damage. Furthermore, the increase of the relative conductivity and MDA content verified this conclusion. These results showed that application of exogenous theanine could make the antioxidant enzyme system imbalance and cause oxidation reactions. Therefore, we concluded that theanine might inhibit the growth of tobacco seedlings by disturbing the equilibrium of the antioxidant system.