茶树凋落叶浸提液对菘蓝生理生化的化感效应

为研究茶树凋落叶浸提液对菘蓝生长与生理生化的化感效应,以模拟自然条件下雨雾淋溶方式,采用不同浓度的茶树凋落叶浸提液(CK:0 mg·mL^-1、T1:6.25 mg·mL^-1、T2:12.5 mg·mL^-1、T3:25 mg·mL^-1 和T4:50 mg·mL^-1)处理菘蓝,测定其生长、抗氧化酶活性及其基因表达量、细胞膜损伤率以及丙二醛(MDA)、过氧化氢(H₂O₂)、渗透调节物质和次生代谢物含量的变化。结果表明,茶树凋落叶浸提液对菘蓝生长表现出“低促高抑”的浓度效应,与CK相比,T1对菘蓝生长具有一定的促进作用,而浸提液浓度超过菘蓝的耐受阈值时,会对其生长产生不利的影响。随着浸提液浓度的升高,可溶性糖和可溶性蛋白含量呈先上升后下降的趋势,而脯氨酸含量则持续增加。与CK相比,T1的MDA含量、细胞膜损伤率和H₂O含量差异不显著,而T3、T4则显著升高。茶树凋落叶浸提液对抗氧化酶活性及其基因表达有不同的影响,T1的过氧化物酶(POD)与抗坏血酸氧化物酶(APX)活性最高,T2的过氧化氢酶(CAT)活性最高,而T3、T4的4种抗氧化酶活性均显著低于CK。T1的Pod、Cat、Apx基因表达量最高,而T4则抑制了抗氧化酶基因的表达。此外,POD活性与其基因表达量呈显著正相关,而超氧化物歧化酶(SOD)、CAT和APX活性与其基因表达量的相关性不显著。不同浓度的茶树凋落叶浸提液对于菘蓝次生代谢物质积累的影响存在显著差异,低浓度茶树凋落叶浸提液对菘蓝生长、靛蓝和靛玉红含量积累有促进作用,而高浓度茶树凋落叶浸提液对总黄酮含量积累有一定的促进作用。本研究结果可为幼龄茶园中茶树-菘蓝复合种植提供理论参考。

Allelopathic Effect of Leaf Litter Extracts of Camellia sinensis on the Physiology and Biochemistry of Isatis indigotica Fort.

By simulating the way of rain-fog leaching under natural conditions, a laboratory experiment was conducted to investigate the allelopathic effect of growth, physiology and biochemistry of I. indigotica exposed to leaf litter extracts of Camellia sinensis (LLEC) (CK: 0 mg·mL^-1,T1: 6.25 mg·mL^-1, T2: 12.5mg·mL^-1, T3: 25 mg·mL^-1, T4: 50 mg·mL^-1). The changes of growth, antioxidant enzyme activity, gene expression, cell membrane damage rate, malondialdehyde, hydrogen peroxide, osmotic regulators and secondary metabolites were measured. The results showed a dose-dependent effect, namely promoting effect at low concentration and suppressing effect at high concentration on the growth of Ⅰ. indigotica. Compared to CK, the growth of Ⅰ. indigotica was enhanced by T1 treatment. However, it was not conducive to its growth when the concentration of LLEC exceeded the tolerance threshold of Ⅰ. indigotica. With increasing the concentration of LLEC, the content of soluble sugar and soluble protein increased first and then decreased, but proline content continued to increase. There were no significant differences between the malondialdehyde content, the cell membrane damage rate and hydrogen peroxide content and CK by T1 treatment. These indicators increased significantly under T3 and T4 treatments. The activities and gene expressions of antioxidant enzymes were affected to different degrees by LLEC. The activity of peroxidase and ascorbate peroxidase by T1 treatment, the activity of catalase by T2 treatment were the highest, but the activities of four antioxidant enzymes by T4 treatment were significantly lower than those of CK. A significant positive correlation was found between the activities of peroxidase and related gene expression level, but the correlation between enzyme activities and related gene expression levels of superoxide dismutase,catalase and ascorbate peroxidase were not significant. Remarkable difference was observed in the accumulation of secondary metabolites in Ⅰ. indigotica under different concentrations of LLEC. The contents of indigo and indirubin were the highest under T1 treatment, and the contents of total flavonoids were the highest under T4 treatment. In conclusion, low concentration of LLEC could promote the growth and accumulation of indigo and indirubin of Ⅰ. indigotica, while high concentration of LLEC could promote the accumulation of total flavonoids. The research provides a theoretical reference for intercropping model of C. sinensis and Ⅰ. indigotica in the young tea field.