Study on plant growth characteristics and diurnal variation of photosynthetic indicators of different young Sapium sebiferum seedlings

The plant growth vigor and photosynthetic characteristics of different Sapium sebiferum seedlings were studied with the one-year-old seedling as experiment material.The results indicated that diurnal variation of net photosynthetic rate for all the tested seedlings showed a bimodal curve,and had distinct lunch break phenomenon.Seedling of No.6 plus plant had medium photosynthetic rate,low water consumption and high efficiency of water utilization.Seedlings of No.12 was low photosynthetic rate,low water consumption and low efficiency of water use.Seedling of No.13 was medium photosynthetic rate,medium water consumption and lower efficiency of water use.Seedlings of No.21 and 23 both were high photosynthetic rate,high water consumption and low efficiency of water use.Seedling of No.24 had low photosynthetic rate,low water consumption and high efficiency of water use.Stillingia oil content positively related with the efficiency of water utilization.Relative height increment of the seedlings positively related with average daily photosynthesis and transpiration rate.Average daily net photosynthetic rate and average daily transpiration rate had significant positive correlation.