Abstract:
Effect of fluoride (F)-stress on the nutrients absorbed by a tea plant was studied. Seedlings of 10-month-old
Camellia sinensis (L.) O. Kuntze cv. Ruixiang grown in pots were fed 3 times weekly for 6 weeks with a nutrient solution containing 0, 100, 200 or 600 mg NaF/L. Contents of F, N, P, K, Ca and Mg in the seedlings were determined. The result showed that F-stress significantly reduced the dry weights of leaves and stems. The ratio of root/shoot (dry weights) declined slightly initially and followed by a significant increase as F concentration reached 600 mg/L. The F contents in the parts, leaves especially, increased with increasing F in solution. Under high F-stress, P in the leaves, stems and roots significantly decreased. In contrast, K in the stems and roots were high under low F treatment and decreased significantly as F concentration was beyond 200 mg/L. Ca in the leaves decreased gradually with increasing F and reduced significantly at the highest F. Mg in the roots significantly declined under 600 mg NaF/L. Otherwise, there were no significant effects on the nutrients in the parts of a plant due to the increased F. The regression equations for contents in leaves between F and total N was determined to be
Y(N)=0.0179
X+28.5509(
R2=0.6662) and between F and Ca,
Y(Ca)=-0.0029
X+1.9852(
R2=0.9864).