Effect Of Interaction Between Water And Fertilizer On Physiological Characters And Biomass Of Phyllostachys Edulis

To study the effect of interaction of water, nitrogen, phosphorus and potassium on Phyllostachys edulis seedling height, root/crown ratio, biomass, nutrient content and physiological characters, an experiment was carried out in the intelligent greenhouse of Zhejiang A&F University with two-year potted Phyllostachys edulis seedlings, by means of the general orthogonal rotation design of quadratic regression with four factors and five levels. The main conclusions were as follows:Concerning the effect of interaction of water and fertilizer on the biomass of Phyllostachys eduli.seeding: under different levels of water stress , the Phyllostachys edulis seeding heights can be ranked as: suitable water>slight flooding>moderate drought>severe drought, suitable water condition is helpful to the height growth of Phyllostachys eduli;among which the height of W_60%N₅P_3.5K_0.9 is maximum, it is 7.45cm. under water stress,appropriate increase of nitrogen and potassium is helpful to the height growth of Phyllostachys edulis,reaching an aim that the fertilizer bring water to play. Under severe drought,the root/crown ratio of Phyllostachys edulis seeding is higher and W_60%N₅P_3.5 contributes to the accumulation of Phyllostachys edulis overground biomass,thus reaching an aim that the water bring fertilizer to play. The influence of four factors to the Phyllostachys edulis seeding dry matter accumulation can be ranked as Water>Nitrogen>Potassium>Phosphorus, the interaction effects of N and P and the interaction effects of N and K all reached the remarkable level of 0.05, while the rest interaction effects fail to get such a level. the best combination of water and fertilizer is W_60%N₅P_3.5K2.6 and dry matter is 49.45g.Concerning the effect of interaction of water and fertilizer on the nutrient content of Phyllostachys edulis seeding: W_20%N_1.9P_3.5K_0.9 inhibits the total nitrogen and total potassium absorption. W_20%N5 contributes to the total potassium absorption by leaf and the total nitrogen absorption by stem and root, the total potassium content in leaf is up to 3.58mg/g, the total nitrogen in stem and root are separately up to 4.91mg/g,4.03 mg/g . W_60%N₅P_3.5 promote the total nitrogen and total phosphorus absorption by the leaf, as well as the total phosphorus and total potassium absorption by the root, the total nitrogen and total phosphorus content in leaf are separately up to10.61 mg/g,2.36mg/g, the total phosphorus and total potassium content in the root are also up to 1.73mg/g,3.21mg/g.Concerning the effect of interaction of water and fertilizer on the physiological characters of Phyllostachys edulis seeding: with the time of stress prolonged, the Phyllostachys edulis seeding under water or nitrogen stress showed following features: (1) the leaf relative water content decreased quickly,and under the suitable water conditions, leaf relative water content changed smoothly and was much higher than the water content under the water stress. (2) the intensification of membrane lipid peroxidation, produced lots of MDA, thus increasing the membrane permeability greatly, among which W_20%N_1.9P_3.5K_0.9,W_20%N5 and W_40%N3.4P7K1.8 increased separately by 54.47%,59.89%,42.6%. (3) SOD activity and POD activity increased firstly and decreased then , among which W_20%N_1.9P_3.5K_0.9, W_20%N5,W_40%N3.4P7K1.8,W_60%N_1.9 increased separately by 37.29%,31.30%,25.30%,22.72%. (4)the content of soluble sugar and soluble protein increased quickly firstly and decreased then, while the content of suitable water and fertilizer deals have no remarkable change. (5) chlorophyll a content,chlorophyll b content and carotenoid content increased gradually in the first days, during which proper increase of nitrogen fertilizer was helpful to the chlorophyll accumulation; W_60%N_1.9 can not facilitate to produce photosynthetic pigment, but proper increase of nitrogen under suitable water and fertilizer condition is helpful to the production of photosynthetic pigment. (6) Fm,Fv,Fv/Fm,Fv/Fo of W_60%N_1.9P_10.5 reach maximum, with the result as follows: 975.33,736.67,0.75,3.09. Yield and ETR are also high, and the Fo and qN of (W_20%N_1.9P_3.5K_0.9) is remarkably higher than the rest deals, which indicated that W_60%N_1.9P_10.5 could contribute to the increase of photosynthesis capacity.