Effect Of Exogenous Silicon On Silicon Uptake Rate And Drought-resistance Of Kentucky Bluegrass

In order to explore the relationship between silicon uptake and utilization and morphological characteristics and physiological characteristics and drought-resistance of Kentucky bluegrass,this paper treated the variety of Kentucky bluegrass "midnight" as material by hydroponic experiment under different concentrations of silicon and different levels of drought in phytotron.This research aimed at building turf and management of measuring irrigation and provided a scientific basis for applying silicon fertilizer.The results were as follows:1.Silicon-absorption kinetics studies show that the curve of silicon-absorption kinetics in different concentration of silicon on Kentucky bluegrass accorded with Michalis-Menten enzyme kinetics model.The Cmin was 0.019,Vmax was 6.18,Km was 0.169,and partly reflected the high responsivity on silicon.2.The 36 hours of silicon absorption test proved that the silicon uptake rate increased significantly in the early stage,the silicon uptake rate became stable in the later stage.The silicon uptake rate of high concentration was significant increase.3.Drought significantly reduced plant height,stem diameter,leaf width,and increased blade wilting degree,reduced turf quality.But silicon significantly reduced the drought stress.Under sufficient water condition and light drought,morphological indexes was significant increase,leaf wilting degree was significant reduce,turf quality increased significantly in 0.5 mmol·L-1;under moderate drought,the plant grew best in 0.35 mmol·L-1;under high drought,the plant grew best in 0.2 mmol·L-1,when the silicon levels greater than 0.2 mmol·L-1,the growth was significantly inhibit.4.Drought stress increased root shoot ratio.Under sufficient water condition and light drought,the high concentration of silicon increased root shoot ratio,promoted roots growth,and root length,root surface area,root diameter and root numbers increased significantly;Under moderate drought,0.35 mmol·L-1 significantly increased the root shoot ratio,and promoted roots growth;under high drought,0.2 mmol·L-1 significantly increased root shoot ratio,and promoted root growth.When the silicon levels greater than 0.2 mmol·L-1,root growth severely inhibited.5.Drought stress reduced the leaf relative water content,but silicon increased significantly the leaf relative water content.Under sufficient water condition and light drought and moderatedrought,0.35 mmol·L-1 was best;under high drought,0.2 mmol·L-1 was best.6.Under drought stress,silicon promoted the accumulation of chlorophyll content.Under sufficient water condition and light drought,the chlorophyll content significantly increased in 0.5mmol·L-1;under moderate drought,the chlorophyll content significantly increased in 0.35mmol·L-1;under high drought,the chlorophyll content significantly increased in 0.2 mmol·L-1,high concentration of silicon significantly decreased chlorophyll content.7.Under drought stress,the silicon reduced leaf relative conductivity and malondialdehyde content.Under sufficient water condition and light drought and moderate drought,0.35 mmol·L-1was best;under high drought,0.2 mmol·L-1 was best.8.Under drought stress,the silicon promoted the accumulation of proline content,the effect of silicon accorded with the plasma membrane permeability index.However,under high drought,when silicon concentration was greater than 0.2 mmol·L-1,proline content was inhibited.9.Moderate drought significantly increased the accumulation of silicon content.Under high drought,the high concentration of silicon drastically reduced silicon element accumulation.Under the low concentration of silicon,silicon element distribution was root > aboveground,when high concentration of silicon,silicon element distribution was aboveground > root.