Effect Of Silicon On Cold Tolerance Of Rice At Early Growth Stage

Rice is an important thermophilic food crop.Low-temperature chilling is an important meteorological disaster in China’s for rice production,and occurs frequently in the northeast in China,which seriously affects the growth and development of rice.Previous researches have shown that silicon can improve the ability of rice to resist low temperatures.In this study,the Dongnong 427 and Silicon preparation were used as a test material.Silicon preparation divided into five treatments,including Si-50(ammonia propyl triethoxy silance),Si-60(3-propyl glycidyl ether oxygen radicals silane),Si-RH(Rice Husk Extracted Silicon),Si-50-G(nano silicon containing amino acid)and Si-60-G(nano crystalline silicon containing epoxy group),were conducted during in the germination,budding and seedling stage of rice.Each silicon preparation was set with three concentrations of 0.010%,0.025%,and 0.050%,and used equal water as CK.Seed soaked in silicon and then germinated at low temperature to count indexes of budding and germination stage.Spraying different silicon preparations on rice in seedling stage and then performing cryogenic treatments(3,5,7days).Germination rate,germination potential and other indices were measured in the germination stage.Seedling rate was calculated in the germinating stage.In the seedling stage,root activity,root and leaf relative electrical conductivity,malondialdehyde(MDA)content,survival rate,root length,and plant height were measured.According to the analysis of the above indicators,the effects of different silicon preparations on the cold tolerance of rice were studied at early growth stage,and the mechanism of different silicon preparations for improving the cold tolerance of rice was revealed.Thisstudy provides a scientific basis for the rational application of silicon preparations to improve the cold tolerance of rice.The results showed that:(1)Seed soaking under low temperature stress with Si-60-G,Si-RH,and Si-60 can significantly improve the rate of seed germinationand the effect of Si-60-G was the most promising.The germination rate can be increased by 14.14%-21.74%,and the optimum concentration was 0.010%.Si-60-G and Si-RH also had significant effects on rice seed vigor.The germination coefficient,germination index and germination potential after soaking of 0.010% Si-60-G were higher than that of the control obviously,with the improvement of 11.2%,23.22%,and 16.4%,respectively.At the suitable concentration,Si-60-G,Si-50-G,Si-60 and Si-RH could remarkably promote the seedling rate of germinating stage and Si-60-G had the most significant effect,when the optimum concentration was 0.025%,which producing an increase of 23.66% compared to the control.Followed by Si-RH,can improve the seedling rate by 23.46%,when the optimum concentration was 0.010%.(2)Both Si-60-G and Si-RH can improve the survival rate of rice seedlings and the cold tolerance,at the optimum concentration of Si-60-G and Si-RH with 0.025% and 0.010%,respectively,the survival rate increased by 7.29% and 9.38%,respectively.At the same time,Si-60-G and Si-RH also had significant effects on rice plant height and root length growth.The effect of Si-60-G was better than Si-RH,and the optimum concentration was 0.025%.At the low temperature of 7 days,the plant height increased by 8.75% and the root length increased by 10.67%.(3)At the suitable concentration,Si-60-G and Si-RH can significantly reduce the leaf relative conductivity and MDA content of rice seedlings.The relative electrical conductivity of leaves treated with 0.025% Si-60-G was the most significant,and it decreased by 11.34%,11.56%,and 9.51% after 3,5,and 7 days of low temperature.The content of MDA in leaves after treatment with 0.010% Si-RH decreased most significantly,and it decreased by 8.15%,6.72%,and 5.27% after 3,5,and 7 days of low temperature.(4)Both Si-RH and Si-60-G can significantly increase root activity of rice seedlings.The effect of Si-RH was better than Si-60-G,and the optimum spraying concentration was 0.010%.After 3,5 and 7 days of low temperature,root vigor increased by 6.70%,10.38%,and 18.35%,respectively.Both Si-60-G and Si-RH can significantly reduce the root relative electrical conductivity and MDA content of rice seedlings.The effect of Si-RH was better than Si-60-G,and the optimum concentration was 0.010%.After 3,5,and 7 days of low temperature,the relative conductivities decreased by 11.58%,9.97% and 8.41%,respectively,the content of MDA decreased by 11.36%,8.84%,and 6.10%,respectively.