Effect of Shading on Growth and Net Photosynthetic Rate of Siraitia grosvenorii in Summer

Taking introduced Siraitia grosvenorii as material,the growth of secondary lateral vine and the rate of net photosynthetic of Siraitia grosvenorii under different shading treatments(0%,20%,45% and 70%)were studied in natural high temperature.The results showed length of lateral vines and interknobs under 70%shading treatment was significantly higher than other shading treatments,but lateral vine diameter,new vine number,leaf thickness,palisade tissue thickness and net photosynthetic rate were significantly lower than other shading treatments.So 70% shading treatment could not be applied to summer cultivation.The lateral vines' length and diameter,new vine number and net photosynthetic rate under 20%and 45%shading treatment were all significantly higher than 0%shading treatment,and there was no significant difference in leaf thickness and palisade tissue thickness between the two treatments.It indicated 45%and 20%shading treatments were both better than full sunshine.Because lateral vines' length and leaf acreage were significantly higher under 45%shading treatment than 20%shading treatment,so 45%shading treatment was the best one.