Effects of fluorine stress on growth, physiological-biochemical characteristics and quality of tea leaves

With a pot experiment, effects of fluorine stress with different concentrations (0—200 mg/kg) on growth, physiological-biochemical indexes of leaves, abilities of accumulating fluorine and quality characteristics in two tea cultivars (Mingshanbaihao and Fudingdabaicha) were studied. The results show that chlorophyll synthesis, tea plant growth and photosynthesis are significantly inhibited with the increase of fluorine stress. Meanwhile, the activities of SOD, CAT and POD in Fudingdabaicha are tended to increase at first and then decrease with the increase of fluorine stress. However, the activities of SOD, CAT and POD in Mingshanbaihao are significantly inhibited. The components of catechin and contents of free amino acids and caffeine, which are the indexes of the quality of tea, are decreased. These results indicate that the fluorine stress might restrain catechin synthesis and nitrogen metabolism. The accumulation of fluorine in tea plant is increased with the increase of fluorine concentration in soil. The total content of fluorine (y) in all organs of tea plant is significantly positively correlated with the fluorine concentrations (x), and the distribution order of fluorine in tea plants was: leaves > new shoots > branches > stems > roots. It's highlighted that Fudingdabaicha has a much better ability of tolerance and resistance to fluorine than that of Mingshanbaihao, while Mingshanbaihao accumulates more fluorine.