氮肥对茶树春季光合、抗衰老特性及内源激素含量的影响

为明确氮肥施用量对春茶优良品种‘乌牛早'(Camellia sinensis ‘Wuniuzao')春季光合等生理特性和内源激素的动态变化的影响,试验设计土壤施氮量为N1(0.4 g/盆)、N2(0.8 g/盆)、N3(1.6 g/盆)和N4(2.4 g/盆),并利用多重比较分析了施氮后各处理随时间变化的情况。结果表明:①施氮处理后‘乌牛早'叶片的光合能力增强,其中叶片叶绿素含量(SPAD值)、净光合速率(P_r)、蒸腾速率(T_r)、气孔导度(G_s)显著增加,胞间二氧化碳浓度(C_i)显著降低,且以N3处理最好,以上各指标分别较对照增加24.36%、26.06%、32.29%和24.49%,C_i较对照降低7.35%。②施氮处理后‘乌牛早'叶片的抗衰老能力增强,以N3处理最强,SOD活性和MDA含量分别是CK的1.14倍和0.75倍。③施氮处理后‘乌牛早'嫩芽中生长素、赤霉素和玉米素含量增加,脱落酸含量降低,以N3处理为最优,各指标分别较CK增加了43.22%、69.08%和54.91%,脱落酸含量较对照降低12.04%。试验表明,春季施氮量为1.6 g/盆时,‘乌牛早'叶片存在较高的光合、抗衰老特性及内源激素含量,说明在春茶生长季增施一定的氮肥能增加茶叶片光合能力延缓叶片的衰老。

Effects of nitrogen fertilization level in soil on physiological characteristics and quality of tea leaves

In order to clarify the dynamic changes of physiological characteristics and endogenous hormone after nitrogen fertilizer on Camellia sinensis ‘Wuniuzao', an experiment was conducted by using the experimental design which included five treatments namely 0.4 g/pot(N₁), 0.8 g/pot(N₂), 1.6 g/pot(N₃)and 2.4 g/pot(N₄)of the nitrogen fertilization level in soil, and no nitrogen fertilization was used as the control(CK). Multiple comparison was used to analyze the significance of each treatment over time after nitrogen application. The effect of different nitrogen levels in soil on the SPAD value, photosynthetic parameters, senescent characteristics and endogenous hormones of tea leaves was studied. The results showed that ① the photosynthetic capacity of ‘Wuniuzao' tea leaves was improved after nitrogen fertilization treatments, in which the SPAD value, net photosynthetic rate(P_r), transpiration rate(T_r)and stomatal conductance(G_s)increased initially and then decreased; the inter cellular CO₂ concentration(C_i)initially decreased and then increased with the increase of the nitrogen fertilization level. Also, N₃ treatment was superior to the other treatments. Compared with the control, the SPAD value, net photosynthetic rate(P_r), transpiration rate(T_r)and stomatal conductance(G_s)increased by 24.36%, 26.06%, 32.29% and 24.49% respectively, C_i decreased by 7.35%. ② The ability of anti-aging increased after fertilizing, and N₃ treatment was superior to the other treatments, SOD activity and MDA content was 1.14 times and 0.75 times of CK. ③ The average contents of Indole acetic acid, gibberellin and zeatin in ‘Wuniuzao' tender buds increased after fertilizing while abscisic acid decreased. N₃ treatment was superior to the other treatments. Compared with the control, the average contents of Indole acetic acid, gibberellin and zeatin increased by 43.22%, 69.08% and 54.91% respectively, abscisic acid decreased by 12.04%. The experiment showed that with the application of a 1.6 g/pot nitrogen fertilization, the ‘Wuniuzao' tea appeared higher photosynthesis and anti-senescence characteristics. The results could provide a theoretical basis for fertilization management to tea tree.