Physiological Growth Conditions Analysis Of Three Apple Rootstock Genotypes Responses To K~+ Deficiency

As one of the most important mineral nutrient elements, potassium has a significant effect on fruit trees. It participates in many plant physiological processes and determines the yield and quality of apple trees. Potassium deficiency can greatly change the growth of the young apple rootstock. Potassium plays an important role in the activity of enzyme, photosynthesis, assimilation product transportation, carbohydrate metabolism, protein synthesis. Plants perceive K~+ deficiency and generate the initial K~+ signal in root cells. This signal is transduced into cytoplasm and caused downstream transcriptional and posttranslational responses, root system produce a series of adaptive events in both physiological and morphological alterations. K~+ translocation from roots to shoots is also be affected under K~+ deficient conditions. In this study, we compared the growth differences of three apple rootstock genotypes responses to K~+ deficiency and analyzed the importance of potassium utilization efficiency for apple rootstock growth and development. The experiments were conducted at Northwest A&F University, Yangling(34°20′N, 108°24′E), shaanxi, China. Seeds of Malus hupehensis Rehd, Malus rockii Rehd, Malus xiaojinensis Cheng et Jiang were collected from national fruit germplasm repository. The results includes four aspects : external manifestation of seedling growth responses to K~+ deficiency, root growth under K~+-deficient conditions, genotypic difference in K efficiency, influence on the photosynthesis、plant height、blade growth parameters and length of primary root of three apple rootstock genotypes under K~+-deficient conditions.