Study On Screening For K-efficiency Rice Varieties And Its Mechanism

This thesis studied22different genotypes rice varieties with pot experiments, theirmain agronomic traits and physiological indexes in the young ear differentiation of latewere investigated under both no potassium and potassium conditions, through varianceanalysis, correlation analysis and factor analysis, combining the harvest index and otherclosely related to potassium efficiency indexes, selected out3potassium efficient varieties,2middle potassium varieties and1potassium inefficient variety through the size ofcomposite index. Then further through the pot experiment, studied the physiologicalcharacteristics and biological characteristics under the condition of four potassium levels,discussed the mechanism of potassium nutrition in the different genotypes rice varieties.The major study results are as follows:(1) Harvest index,relative yield, the relative tiller number and relative spike grainnumber can be used as main indicators of composite index under the condition of withoutpotassium and potassium, in combination with relative chlorophyll and relative plantheight,screen out6rice varieties,3potassium efficient varieties, including Teyou2089,Teyou524and Huangfengzhan;2middle potassium efficient varieties, including Teyou248and Wuguangzhan;1potassium inefficient variety, it provides the basis materials forfurther study on potassium efficient in the aspect of physiological mechanism.(2) Potassium efficient varieties significantly greater than the varieties of lowefficiency of potassium in their harvest index, biomass, yield and seed setting rate underthe condition of low potassium, and significant difference was found in different conditionsunder the same potassium level. But with the increase of potassium level, the abovecharacteristics reached the maximum at K1level, it tends to be stable in the later.(3) Whether potassium efficient varieties or potassium inefficient cultivars have noobvious difference in the number of grain per ear and thousand seed weight, ear length,plant height and other agronomic traits under different potassium levels.(4) Potassium efficient rice cultivars were higher than other varieties with chlorophyllcontent, significant difference was found in chlorophyll content between the differentspecies under the same potassium level.(5) Potassium efficient rice varieties were higher than other varieties in the soluble sugar content and soluble protein content in the condition of low potassium, but potassiumefficient varieties is lower than other varieties in the proline content, there were differencesamong different rice varieties, the change of proline content was affected by potassium.(6) Potassium efficient varieties were larger changes than other varieties in the activityof POD in the condition of low potassium, but CAT ativity change smaller in the sameconditions, this show that the closely relationship between potassium efficiency andantioxidative enzymes activities.