The Influence Of Photosynthetic And Biological Characters With Nitrogen Application Rate

Weedy rice,mixed in rice field,has a series of excellent adaptability,such as strong tillering,large plant,disease resistance,drought tolerance and so on.It has strong competitiveness to light and nutrition.Nitrogen is an important element with rice yield.In the past,nitrogen fertilizer was used blindly and overmuch in order to increase rice yield.Nowadays,the state puts forward the goal and plan of "lose fertilizer and increase production".Based on this background,the difference of photosynthetic and biological characters of weedy rice under different nitrogen application levels were studied in order to provide important germplasm resources for low nitrogen and high efficiency varieties.Photosynthetic characteristics of cultivar Jijing81(C81),weedy rice WYB,WQ,W854,hybrid materials H10,H11 and H12 are studied by photosynthetic apparatus and chlorophyll fluorescence analyzer.The maximum photosynthetic rate(Pnmax)of local weedy rice WYB is significantly higher than cultivar C81 in the response of photosynthetic rate to light intensity.The Pnmax of the hybrid material H11 is significantly lower than C81.In the study of the response of photosynthetic rate to carbon dioxide,weedy rice WQ response curve is lower,the Pnmax of cultivar C81 and hybrid material H11 and H12 are the largest and there is a high photosynthetic rate at the concentration of saturated C02.In the response of stomatal conductance to light intensity,the stomatal conductance of each material increased rapidly with the intensity of light intensity,and the stomatal conductance was maintained under certain light intensity within a certain range.In the response of stomatal conductance to leaf C02 concentration,stomatal conductance decreased with increasing C02 concentration.In the study of chlorophyll fluorescence parameters and rapid light curve,the electron transfer rate of C81,H10,H12,W854 and WYB is slightly larger.The rapid light curve fitting value ETRmax of weedy rice WYB and hybrid material H10 is significantly higher than cultivar C81,WYB and H10 have better photosynthetic physiological characteristics.The results showed different kinds of weedy rice?cultivated rice and hybrid materials have different photosynthetic?physiological characteristics Compared with the conventional cultivar Jijing 81,the local weedy rice had some advantages over some photosynthetic characteristics.Under the different nitrogen application levels,the photosynthetic and biological properties of various materials were studied.Under the no nitrogen application level,the actual photochemical efficiency(Y(II)),photochemical quenching(qP)?electron transfer rate(ETR)and Pnmax of weedy rice W25 is the best than other materials.Under low nitrogen level,Y(II),qP,ETR of weedy rice W25,WYB and hybrid material H12 are significantly higher than other materials,and the Pnmax of H12?W25 are significantly higher than other materials.Under the medium nitrogen level,the fluorescence parameters of hybrid material H11 are the smallest,and the Pnmax of weedy rice C511 is the largest.Under the high nitrogen level,the fluorescence parameters ETR,rapid light curve fitting parameters ETRmax and photosynthetic parameters Pnmax of cultivar C81 are both higher,photosynthetic characteristics are better.In the study of biological traits at maturity,Under the no nitrogen application level,weed rice W25 have the highest number of spike,the highest total nitrogen content in stem and leaf,and the highest yield per hole.Under low nitrogen application level,the total nitrogen content of stem and leaf of hybrid material H12 and weedy rice WYB are significantly higher than other materials.The yield of weedy rice W2 is the highest,which is significantly higher than cultivar C81 and C511.Under the medium nitrogen level,there is little difference in the number of spikes among the materials,the number of C81 spikes is the most,and the total nitrogen content in the stem and leaf of hybrid material H12 is the most,and the yield of C511,H13,WYB and W2 are relatively high.Under high nitrogen level,the W2's number of spikes is the highest,the total nitrogen content of stem and leaf of WYB and W2 are the highest,and the yield of WYB and W2 are the highest.In short,under the no nitrogen application and low nitrogen application level,some weedy rice or hybrid materials showed better photosynthetic and fluorescence parameters than cultivated rice.With the increase of nitrogen application level,some photosynthetic and fluorescence parameters of cultivated rice are changed better Some photosynthetic parameters of cultivated rice are better than weedy rice or hybrid rice.