The Effect Of Minerals N P K Mg On The Photosynthesis Of Hevea Brasiliensis

The photosynthesis is the foundation of the rubber tree yield formation. Minerals not only provide nutrient substance for the rubber tree growth,but also is an important factor which influences its photosynthesis. In this research,Young buddings of Clone SCATC 7-33-97 were used as plant materials,adopting to the quadratic general rotary unitized design,with nitrogen,phosphor,potassium,magnesium these four factors with 5 levels(1/2 implement) for fertilizer experiment. We research the effect of different fertilizer combination and leaf minerals content on the photosynthesis of rubber tree mainly from photosynthetic rate,stomatal conductance,chlorophyll content...etc.,and filter the best fertilizer combination which promoting rubber tree photosynthesis efficiently proceeding, the aim is to provide basal theories for the cultivation of rubber tree. The results are as follow:1. In a certain fertilizer applying scope,the leaf photosynthetic rate,stomatal conductance and chlorophyll content increased with fertilizer applying quantity,but declined after a certain point. The effect degree of N fertilizer (Urea),P fertilizer(Calcium superphosphate),K fertilizer (Potassium chloride),Mg fertilizer(Magnesium sulfate), under different level is : (1) N(g/kg土),0.375 > 0.75 > 0 (P,K,Mg are 0.875,0.2, 0.125 g.kg-1 respectively); (2) P(g/kg土),0.875 >1.75 >0 (N,K,Mg are 0.375,0.2, 0.17 g.kg-1 respectively); (3) K(g/kg土),0.2 > 0.4 >0 (N,P,Mg are 0.375 0.875, 0.125 g.kg-1 respectively); (4) Mg (g/kg土),0.125 > 0.25 >0 (N,P,K are 0.375, 0.875,0.2 g.kg-1 respectively).2. There is a linear relation between the N,P,K,Mg content and the photosynthesis rate of rubber tree leaf. In a certain scope of the N,P,K,Mg content,namely in the N content 2.51 ~ 3.52%,the P content 0.177 ~ 0.258%,the K content 0.72 ~ 1.58%,the Mg content 0.206 ~ 0.378%,the photosynthesis rate increased with the increasing of N.P,K,Mg content of rubber tree.3. The N fertilizer is the first factor which influenced the photosynthesis rate among the four fertilizers (N,P,K,Mg fertilizer),following the P fertilizer,the K fertilizer and the Mg fertilizer is unobvious comparatively. Under the lower fertilizer applying level,the change scope of photosynthesis rate which influenced by each fertilizer is more obvious than that under the higher fertilizer applying level. The chlorophyll content and stomatal conductance show a similar current with the photosynthesis rate.4. There is an interactive effect between N,P,K,Mg fertilizer. The interactive effect sequence as follows: N,P> N,Mg> N,K.5. The most effective prescription of fertilizer applying on rubber tree photosynthesis rate are as follows: the Urea is 0.55 g.kg-1,the Calcium superphosphate is 0.14 g.kg-1,the Potassium chloride 0.23 g.kg-1,the Magnesium sulfate 0.19 g/kg soil.