Effect of water and nitrogen treatment on photosynthetic characteristics and the biomass allocation of annual cutting seedling of Machilus pauhoi
To investigate the effects of water and nitrogen on photosynthetic characteristics and biomass allocation of Machilus pauhoi,one-year old cutting propagated Machilus pauhoi plants potted in greenhouse were treated with different gradients of water and nitrogen.The results showed that:(1) Drought stress significantly reduced the net photosynthetic rate (Pn),stomatal conductance (Gs) and transpiration rate (E),total biomass and leaf weight ratio,while the stem weight ratio increased;however,the influences on intercellular CO2 concentration,root weight ratio and root shoot ratio were not significant.(2) Pn,Gs and E in the low-nitrogen addition group were higher than CK,but addition of high-nitrogen inhibited the photosynthesis.The total biomass in the nitrogen addition groups (LN and HN) was higher than in CK.The effect of nitrogen addition on the biomass allocation trend in different organs was not obvious.(3) The interaction between water and nitrogen addition had no significant influence on the photosynthetic characteristics and biomass allocation of the plant.Therefore,we must provide sufficient water during the process of plant growth.
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