Effect Of Different Phosphorus Levels On Growth And Some Nutrient Elements Absorption Of Rice Seedlings

Rice as an important cereal crops, the total cultivated area and production position in the world of food crops after wheat. Rice production is particularly important in our country, rice production accounts for over2/5of the total grain output in China, however, the present situation of the cultivated land in our country is about more than about half of the soil is deficient in phosphorus, especially the south hidden fertility paddy soil phosphorus deficiency phenomenon is more serious, which restricted the production of rice in large part of our country. By applying phosphate fertilizer can solve the situation of shortage phosphorus, however, the lack of phosphate rock resources, plant phosphorus excess of low utilization rate of phosphorus removal and applied into the pollution to the environment and brought new challenges, therefore, to study the effect of different phosphorus levels on rice growth, explore the mechanism of phosphorus removal using rice root morphology and response of different concentration of exogenous phosphorus fertilization on the production, improve rice p use efficiency, has the vital significance to further increase rice production. In this study, Zhenshan97B and Miyang46as the experimental material, through different levels of phosphorus processing, set the normal phosphorus level as control (CK), studied the effects of different levels of phosphorus on rice growth and some nutrient elements absorption. The results were as follows:1、Low phosphorus levels were significantly increased the plant height of two varieties, reduced the number tillers of Zhenshan97B, but increased the number of tillers of Miyang46significantly; High phosphorus levels on the effect of plant height and tiller number is due to the difference between different varieties and processing period. Low phosphorus levels increased the biomass of two cultivars, high phosphorus levels inhibited the biomass of Zhenshan97B, and increased the biomass of Miyang46after10d treatment. But in the treatment of20d, low phosphorus levels in addition to promoted the root dry weight of Zhenshan97B, inhibited the increasing of rice seedling biomass, high phosphorus levels were in contrast to the treatment of the10d, increased the biomass of Zhenshan97B, and inhibited the biomass of Miyang46. Overall, low phosphorus levels increased the SPAD value of rice seedling leaves, high phosphorus levels reduced the SPAD value of rice seedling leaves. Low phosphorus levels increased the chlorophyll a, chlorophyll b and the content of carotenoid of Miyang46, as for zhenshan97B performaced inhibition after10d treatment and performaced processing after10d treatment; High phosphorus levels due to the different varieties and different clinical manifestations of quite different.2、Low phosphorus increased the CAT and POD activity of rice leaf significantly, high phosphorus levels reduced the CAT of leaf and POD activity of root. Exogenous low phosphorus and high phosphorus levels were reduced SOD activity of rice seedlings roots after treatment20d. Low phosphorus levels increased MDA content of leaf and root of Zhenshan97B, decreased MDA content of leaf and root of Miyang46; High phosphorus levels reduced the MDA content of leaf and root of two rice cultivars.3、Except when dealing with20d low phosphorus levels had no effect with root surface area, root volume and average diameter comparing with contrast of Miyang46, low phosphorus levels increased the longest root length per plant, total root length, root surface area per plant, plant root volume, root average diameter, number of root and root fractal dimension of two rice varieties obviously; High phosphorus levels decreased the longest root length, total root length and root number per, two varieties increased plant root surface area, root volume per plant, root average diameter and root fractal dimension of Zhenshan97B.phosphorus levels reduced the root CEC of two rice cultivars significantly, high phosphorus levels increased the root CEC of Zhenshan97B significantly, while had less affect in Miyang46.5、Low phosphorus levels reduced the shoot and root phosphorus element content of two cultivars significantly and high phosphorus levels significantly increased the shoot and root phosphorus element content of two cultivars significantly. Low phosphorus levels increased the shoot iron content significantly, reduced the root iron content; High phosphorus levels reduced the shoot iron content of Zhenshan97B and root iron content of Miyang46, increased root iron content of Zhenshan97B and shoot iron content of Miyang46. Low phosphorus levels reduced the shoot and root manganese and zinc content significantly or extremely significantly; High phosphorus levels increased shoot and root manganese content of two cultivars in addition to the shoot manganese content of Miayng46after10d treatment, high phosphorus levels reduce the shoot and root zinc content of Zhenashan97B and increased the shoot and root zinc content of Miyang46. Exogenous different phosphorus levels concentration was almost no effect on copper content of the rice seedlings.