Responses Of Root Development And Grain Quality To Phosphorus And Potassium In Winter Wheat (Triticum Aestivum L.)

The studies were carried out in the Scientific and Educational Park of Henan Agricultural University in 2007-2009. Test Root development research using potted, in 2007-2008 high-quality wheat cultivars in Huanghuai wheat area were used: Zhengmai 004(weak-gluten wheat cultivar), Zhoumai 18(medium-gluten wheat cultivar), Zhengmai 9023 (strong-gluten cultivar )were used as materials. Research the effects on different levels of phosphorus of wheat root stretchy, fruit characters and physiological properties of yield and quality. In 2008-2009 used Zhengmai 004 and Zhengmai 9023 as materials. Research the effects of winter wheat root stretchy quantitative traits and physiological traits, grain yield and quality under different phosphorus and potassium application rates. The main results are as follows:(1) Effect of phosphorus in different application levels on the morphological, quantitative and physiological traits of the root system were made clear. Root-shoot ratio was the highest in control, under the medium phosphorus application level, the number of secondary roots per plant and root activity increased in different degree, but the effect of soluble sugar contention in root is not significant. The high phosphorus level significantly reduced dry root weight per plant and root-shoot ratio, increased soluble sugar contention in root. The results showed that, in the experiment condition, overdue phosphorus application (high phosphorus level) did not mean improving morphological, quantitative and physiological trails of roots. Quantitative and physiological trails of roots of strong-gluten cultivar Zhengmai 9023 were lower than those of weak-gluten wheat cultivar Zhengmai 004 and medium-gluten wheat cultivar Zhoumai 18. These results also showed that difference existed in root development of cultivars of different quality types.(2) Effect of phosphorus and Potassium in different application levels on the morphological, quantitative and physiological traits of the root system were made clear. Generally, the secondary roots per plant,root volume were higher under P(120)K(100) treatment. The root dry weights and the root activity of Zhengmai 004 were higher under P(120)K(0) treatment, Zhengmai 9023 were higher under P(120)K(100) treatment. Soluble sugar content in root under K (200) level is higher in earlier growing stage, but no significant difference in later growing stage. Quantitative characters of the root system of Zhengmai 004 were better than those of Zhengmai 9023. Effect of morphological, quantitative and physiological traits of the roots were different under the different of potassium and phosphorus treatments, the effects also has difference of cultivars of different quality types.(3) The effect of yield and quality trails of grains in different levels of phosphorus were made clear. At the same level of nitrogen and potassium, by changing the number of ears, grains per spike and 1000-grain weight, phosphorus application increased yields. The starch contents of Zhoumai 18 and Zhengmai 9023 increased significantly, but phosphorus effect decreased by high phosphorus level; Phosphorus application significantly reduced the protein content of Zhengmai 004, and increased the protein contents of Zhoumai 18 and Zhengmai 9023. The protein content of Zhoumai 18 was the highest in high phosphorus level.(4) The effect of yield and quality trails of grains in different levels of phosphorus and potassium were made clear. At the same level of nitrogen, the yield of Zhengmai 004 was the highest under P(120)K(0) treatment, the yield of Zhengmai 9023 was the highest under P(120)K(100) treatment. Phosphorus and potassium application reduced the amylose content, the starch content of Zhengmai 004 was the highest under P(120)K(100) treatment, the starch content of Zhengmai 9023 was the highest under P(0)K(100) treatment, both of those reached extreme significant level; the protein content of Zhengmai 004 was slightly decrease, the protein content of Zhengmai 9023 was increased significantly under P(120)K(100) and P(120)K(200) treatment. From the comprehensive effect of yield and quality, the effect of P(120)K(100) treatment was better, but potassium application for Zhengmai 004 should be slightly lower than Zhengmai 9023.(5) Correlations between root traits and grain quality traits were analyzed among cultivars of different quality types. In Zhengmai 004, significant positive correlations existed between secondary roots and soluble sugar contention in roots in early growing stage and starch content in grains, significant positive correlations existed between secondary roots and starch content in grains of Zhoumai 18 in mid-later growing stage, positive correlations between secondary roots per plant and root volume per plant of Zhengmai 9023 in middle growing stage and starch content in grains were significant, significant negative correlations existed not only between secondary roots per plant and protein content in grains of Zhengmai 004 in later growing stage, but also between root vigor and protein content in grains in early and middle growing stage, positive correlations between secondary roots per plant and protein content in grains of Zhoumai 18 were significant in middle growing stage, significant positive correlations existed not only between root volume per plant and root vigor in early growing stage and protein content in grains of Zhengmai 9023, but also between secondary roots per plant and protein content in grains in later growing stage. The date indicated that it might be feasible to improve grain quality by regulating root development in the production practice due to significant correlations existing between root traits and grain quality traits.