Effect Of Shading On Growth And Physiological Character Of Cigar-Wrapper Tobacco

The paper studied growth and physiological capabilities of cigar-wrapper leaves and pointed at the optimum parameter index of shading in the field in 2005-2006.the conclusion was induced in the following inspect:(1)The study about the effect of different shading on growth in cigar-wrapper pointed that the difference of light density could influence the process and characteristic of growth.it showed that as the shading ration added,tobacco stems and leaves separately became slender and thinner,the plant heights and leaf areas of tobacco increased firstly and then declined,.the rate of root dry weights/total dry weights was not significantly different and the rate of leaves dry weights/the total dry weights increased significantly as the decline of light density.The study induced that there was optimum environment of growth at the treatment of L1,but there was the optimum need at the treatment of L2.(2)The study about effect of different shading on photosynthesis capabilities in cigar -wrapper induced that there were slight difference among different treatments of shad ing and the different process of growth of leaves where Fv/Fm is concerned,the rea son was not analyzed at the present,the module of PFD-P_n was similar to parabola with two index.it could induce that as the shading ration increased,light compensa tion point and light saturation point declined.The conclusion of Ls could induce that in the lowest light density,P_n was limited mostly by the Gs in the the treatment of L2 and L3,P_n was limited mostly by light density in the treatment of L1;the shadi ng could make the chlorophyll content to increase and the chlorophyll a/b ration to decline.there were different significantly in the different treatment of shading where chlorophyll content is concerned.but there were not different change under the differe nt treatment of shading in the case of the chlorophyll a/b ration,it showed that it c ould relieve the menace of light under shading(3)The study about effect of different shading on hormone content and activity of enzyme in cigar-wrapper opened out that it was unanimous that the content of IAA,ABA gradually increased in the process of growth in different treatment of shading,the content of GA,ZR increased firstly and then declined,on the contrary,the activity of NR,GS gradually declined,as the shading ration increased,content of IAA,GA gradually appeared the trend of Lck＞L1＞L2,the content of L3 was not the lower than at the treatment of the other.the content of ABA gradually increased,the content of ZR appeared the trend of L3＞L2＞Lck＞L1,the activity of NR,GS gradually declined.(4)The study about effect of different shading on general chemic component and rat ions in cigar-wrapper pointed at that the balance of metabolize between the nitrogen and carbon was changed in the different treatment of shading,in the result,there we re significantly different in the inspect of general chemic component in the case of t he mature leaves in the different treatment of shading,we could make a decision tha t nicotine content was lower,the content of total nitrogen,reverted sugar and total sugar is middle,the ration of total nitrogen/total sugar ration is middle in the treat ment of L2.the result pointed at that it was the better position of the regular chemi cal component and ration in the treatment of L2(5)The study about effect of different shading on cellular matter of leaves concocted in cigar-wrapper pointed at that it was remarkable different of fibrin between the tr eatment of shading and Lck;it was slightly different of self-fibrin among the four ki nd of treatments of shading;it was remarkable different between the treatment of L 3 and L1 or Lck.(6)The study about effect of different shading on organizational structure of leaves 1 ied in the middle of cigar-wrapper pointed at that organizational structure was chang ed in the different treatment of shading,at the same time pointed at that in the cert ain of shading(L1,L2),the negative effect caused the lack of light can be remedied through stimulating growth of barrier,but in the treatment of deeply shading(L3),o rganizational structure of leaves limited the photosynthesis capabilities.