Abstract:
Two yearold seedlings of tea plants (
Camellia sinensis cv. Tieguanyin and
C.sinensis cv. Fudingdabaicha ) were cultivated in a pot experiment to investigate the photosynthetic parameters with light intensity of PAR 0 ~ 2 000 μmol·m
-2·s
-1 under four water stress treatments: 75% (normal water supply), 55% (slight water stress), 35% (mild water stress) and 20% (severe water stress) of soil field capacity. The results show that light response curves of net photosynthetic rate (
Pn ) in “Tieguanyin” and “Fudingdabaicha” tea plants follow an exponential equation model. Under normal water supply condition, “Tieguanyin” and “Fudingdabaicha” maximum net photosynthetic rates (
Pnmax) are 8.169 μmol(CO
2)·m
-2·s
-1 and 3.946 μmol(CO
2)·m
-2·s
-1; apparent quantum yields (
AQY ) are 0.039 μmol(CO
2)·μmol
-1 and 0.024 μmol(CO
2)·μmol
-1; light saturation points (
LSP ) are 973.07 μmol·m
-2·s
-1 and 775.78 μmol·m
-2·s
-1; light compensation points (
LCP ) are 5.15 μmol·m
-2·s
-1 and 6.49 μmol·m
-2·s
-1; and dark respiration rates (
Rd ) are 1.025 μmol(CO
2)·m
-2·s
-1 and 1.040 μmol(CO
2)·m
-2·s
-1 respectively. Under soil drought stress,
Pnmax,
AQY and
LSP decrease while
LCP and
Rd increase. Compared with “Fudingdabaicha”, “Tieguanyin” presents higher
Pn,
Pnmax,
LSP and
AQY, but lower
LCP and
Rd ; indicating that “Tieguanyin” has higher adaptation capacity to different soil water supply and light intensity than “Fudingdabaicha” under the same environmental conditions.