Abstract:

A field experiment was conducted with Aconitum kusnezoffii to investigate effects of alternate partial root zone drying(APRD), fixed partial root zone drying(FPRD),and whole root zone irrigation (BPRI) on photosynthesis characteristics of two-year-old A. kusnezoffii, aimed at providing a theoretical basis for cultivating this kind of plant for the arid area. The results showed that, 1)The transpiration rate(Tr) in all three treatments were decreased gradually with experimental time. The peak value decreased and the peak point moved forward with the aggravated water stress. 2)A. kusnezoffii in APRD treatment had lower stomatal conductance than the other treatments, and the net photosynthetic rate(P_</em>n)was higher than BPRI and FPRD by 4.16% and 37.43% respectively when the Tr in APRD treatment was decreased than BPRI by 30%, reflecting that the APRD treatment could optimally adjust the stomatal behavior. 3)The diurnal change of water use efficiency in three treatments was all double peak curves. The WUE in the APRD treatment was significantly higher than that in BPRI and FPRD by 20.39% and 10.53%, respectively.(4)The photosynthetic light response curve in the three treatments was generally similar. The apparent quantum yield (AQY) of photosynthesis in three treatments was similar to each other. The collaborative variation of light saturation point (LSP) and light compensation point (LCP) showed that the ability to adapt to light in the treatment of APRD was enhanced to some extent. The maximum net photosynthesis rate(P)in the APRD treatment was the highest. The dark respiration rate (R_</em>d) in the APRD treatment was lowest, suggesting that A. kusnezoffii reduced its consumption so as to adapt arid environment. Alternate partial root zone drying(APRD) developed the biological water-saving potential plants by regulating water supply.max

Key words: alternate water stress, water use efficiency, photosynthesis light response, Aconitum kusnezoffii