Effects Of Brassinolide On The Nutritional Growth Of Two Shoot Bamboo Species

Brassinolide（BR）is a kind of steroid hormone and promotes the growth of plants.The bamboo flowering could pose a severe threat to the management and development of bamboo.The effects of BR on bamboo physiological and biochemical indices on the flowering bamboo forest are studied to promote the growth of the nutritional growth of bamboo,which can provide the correlative experience and scientific criteria for the restoration technology of the flowering bamboo forest that may appear in the future.In this work,the Phyllostachys edulis and Phyllostachys violascens are used to research the effects of BR on the nutritional growth of bamboo.1.The leaves on the Phyllostachys edulis seedlings are sprayed with various concentration of BR(0μg·L^-1,50μg·L^-1,10μg·L^-1,5μg·L^-1,1μg·L^-1,0.5μg·L^-1).the results showed that compared with th e CK,when the BR concentration was 5μg·L^-1,the root-shoot ratio of the seedlings was 17.8%lower,a nd the ratio of soluble sugar and soluble protein content was 15.7%lower.At the same time,the nitroge n,phosphorus and potassium content in the leaves of Phyllostachys edulis seedlings were effectively in creased under this concentration,and the photosynthetic capacity and antioxidant performance of the pla nts were improved,which promoted the vegetative growth of Phyllostachys edulis seedlings.2.In the test of the flowering Phyllostachys violascens Cavity with the injection concentration of5μg·L^-1 BR,the leaf N,P,K content are much lower than that of the no-flowering bamboo,but the changes present the tendency of going up gradually.In the next February,the N,P,K content of the flowering bamboo are higher than that of the no-flowering bamboo by 18.3%、15.9%and 24.1%,and the Chl-a,Chl-b,and total chlorophyll content are increased by 23.7%、33.3%and 25.8%than that of the untreated.Also,the Net Photosynthetic Rate is increased by 28.8%.Meanwhile,the soluble carbohydrate content and the soluble protein content in the leaves are also improved with its smaller ration of 12.6%compared to that of the untreated flowering bamboo.3.After the injection of 5μg·L^-1BR in the whole stand,the photosynthetic capacity,nitrogen,phosphorus and potassium content of leaves of Phyllostachys violascens in the flowering bamboo forest increased before the May of the following year.Compared with those untreated,the ratio of soluble sugar and soluble protein in the leaves of Phyllostachys violascens increased after the treatment,at the same time the ratio of the two decreased by 20.5%;the activity of glutamine synthetase and nitrate reductase increased by 28.9%and 39.0%respectively.Nitrogen metabolism in the leaves of Phyllostachys violascens increased,sothe flowering number of the new culms is reduced significantly.After BR treatment was stopped in June of the following year,the indicators of Phyllostachys violascens in the woodland were higher than those of untreated in November of the following year,and the ratio of soluble sugar to soluble protein content in the leaves was still lower than that of untreated.Above all,the ration of the soluble carbohydrate content and the soluble protein content can presents the basic state of C/N metabolize activity.The BR treatment can effectively reduce its ratio in the bamboo community,coordinate the metabolism of C/N,improve the photosynthetic performances and influence the N,P,and K uptake and accumulation.Then the nutrition growth of the bamboo can be promoted.