Effect Of Potassium Fertilizer On The Starch Accumulation Of Japonica Rice At Different Panicle Positions In Cold

Heilongjiang Province is the mainly province in North rice of cultivation area.It is one of the main origin of high-quality rice and important commodity grain production in our country.Potassium is the largest demand nutrients for process on rice growing.Rice seed germination to harvest nitrogen, phosphorus and potassium from the demand ratio of 1 : 0.5 : 1.3.Therefore, the most nitrogen demand is the potassium.However, the soil is supplied to the rice little potassium.Three japonica rice varieties, Dongnong 425, Dongnong 427 and Songjing No. 6,were studied by field experiments with K2 O rates as K0(0kg·ha-1), K1(25kg·ha-1), K2(50kg·ha-1), K3(75kg·ha-1), K4(100kg·ha-1), K5(125kg·ha-1)and K6(150kg·ha-1), to explore the Effects of potassium fertilizer on the Starch accumulation of Japonica rice at different panicle positions in cold region,In order to clarify the relationship of canopy structure、flag leaf nitrogen potassium ratio and starch accumulation.Effects of Potassium amount of grain filling characteristics and yield of ear.In order to reveal the effect of the accumulation of different laws and Ear amount of potassium to the formation of cold rice grain starch and rice production in the cold region for rational application of potash to provide a theoretical basis.The test results are as follows:(1).With the number of days to promote filling each ear three varieties of total starch content was gradually increasing.DongNong 425, K3, K4, K5 treated separately in favor of the increase in the accumulation of total starch in the lower part of the ear.Songjing 6, K5 treatment conducive to the accumulation of total starch ministries ear.DongNong 427, K3, K5, respectively, in favor of the deal, the accumulation of total starch in the middle part of the ear.With the number of days advance grout, three varieties of each part of the ear proportion of starch accumulation was increasing linear trend.Potassium volume ratio of amylose accumulation less affected each period.Three varieties of each ear amylopectin starch accumulation variation with total same and Its variation also varies by species.Effect of potassium on the total amount of starch and amylopectin in the early and middle filling grout always smaller,But in the late filling the right amount of potassium can significantly increase the total starch content and amylopectin content of ministries ear.(2).Three varieties of grain soluble sugar content with the advance of the process of gradually reducing grout,Soluble sugar content with increase in the amount of potassium after increased first increased and then decreased.Three parts of the ear change sucrose content varies by species.The single peak curve of three varieties of ear of grain ADPG pyrophosphorylase, starch synthase, starch branching enzyme activity was in the grouting process.ADPG pyrophosphorylase and starch branching enzyme were peaked at 21 days after heading, starch synthase in peaked at 14 days after heading.Three varieties of each part of the ear ADPG pyrophosphorylase activity peak size appear to be Songjing 6 ’maximum’ Dongnong 425 and Dongnong 427.Effect of potassium on starch synthase varies by species.Potassium application effect on the activity of starch branching enzyme is the largest Dongnong 425, Dongnong 427 is minimal impact.(3).At the beginning of the formation of starch, there was significant positive correlation between ADPG pyrophosphorylase activity and total starch, amylopectin accumulation.Starch synthase on starch formation and accumulation of the impact is bigger, the influence on the amylopectin content greater than the amylose content, the influence on the upper and middle ear starch content is larger than the lower part of the ear.Starch synthase on starch formation and accumulation of great influence,influence of amylopectin content greater than amylose content,The influence on the upper and middle ear starch content is larger than the lower ear.Starch synthase and starch accumulation in each ear in 21~35 days after full heading correlation.(4).During the grain filling of canopy light transmittance rate relation is ripe stage maximum, minimum milk ripe stage.Three part of canopy light transmittance rate is lower than the central relationship: than the upper.Suitable K amount can be reduced canopy transmittance, raise the canopy of each part of the absorption of PAR.Compared with no K, appropriate amount of potassium increased significantly on the 3 leaf area,In K3、K4 treatment, rice leaf angle three minimum, the largest leaf area.Three cultivars of nitrogen and potassium ratio in each period are increased,After reaching a maximum and declined in K4 and K5 treatment,That in a certain range, the application of potassium fertilizer could promote the absorption and utilization of nitrogen in Rice.Three varieties in each treatment of the sword leaf nitrogen to potassium ratio showed waxy ripe stage maximum, minimum, and some differences between varieties.(5).With the increase of potassium, initial growth potential of the upper ear(R0) decreased gradually, while in the lower part of ear, R0 increased gradually, and in K3(Dongnong 425, Dongnong 427), K4(Songjing 6) processing the maximum.The average filling rate of three varieties with different spike grain(GRmean) were increased with the increase of potassium fertilizer application increased first and then decreased, the average grain filling rate and ultimately each ear of grain(GRmean) under K6 treatment the smallest difference.In a certain range with the increase of potassium, grain filling duration(D) increased.The different filling stage contribution rate to yield a smaller difference between varieties, ear varied; potassium of smaller amplitude in the upper part of ear filling contribution rate.(6).The suitable application amount of potassium fertilizer can significantly increase the yield of rice.Among them, Dongnong 425 under K3 treatment and K4 treatment of the largest output, the difference was not significant, significant differences with other treatments.Dongnong 427 under K3 treatment the largest output, and K4, K5 treatment did not show significant difference, significant differences with other treatments.Songjing 6 under K4’s largest production, significant differences with other treatments.The main effect of potassium in the middle ear and the seed setting rate and 1000 grain weight lower ear, then on the upper and middle ear seed setting rate and 1000 grain weight at the lower part of ear.The degree of sensitivity of Dongnong 425, Songjing 6, Dongnong 427 to Potassium different, including Dongnong 425 K on yield increased rapidly, and Dongnong 427 in K yield slow increase sensitivity of minimum.(7).In K2、K3 processing of all varieties of potash partial productivity and agronomic rate maximum,While the varietal differences, Songjing 6 in partial productivity under different treatments were higher in the high potassium fertilizer, potassium treatment agronomic use efficiency is higher than other varieties and The lowest rate of utilization of Dongnong 427 potash agronomy.Dongnong 425 and Dongnong 427 potassium application amount in 50-75 kg · ha-1, Songjing 6 potassium application amount in 25-100kg·ha-1 fertilizer utilization rate and yield can reach the highest.