Comparison Of P Uptake Related Root Morphological And Physiological Traits Of Some Cotton Genotypes

To investigate efficiency of differences phosphorus cotton in the use of phosphorus, this paper clarified the relationship between root morphological and characteristics of rhizosphere. Two different P-efficient cotton genotypes(the three of P-efficient XH18,ZM42,XLZ19 and the two of P-inefficient XLZ13 and XLZ17) were selected for the study. Crop biomass, P uptake amount, root morphology, Olsen-P, pH and phosphatase activity in the rhizosphere were measured. To explore the mechanism of the cotton phosphorus utilization, as well as the cultivation medium root morphology and the different characteristics of rhizosphere. The main conclusions are as follows:(1)Growth characteristics of some P cotton genotypes are affected by different P sources. Result showed that under the sand culture and soil culture phosphorus content increases the efficiency of different phosphorus cotton biomass and accumulation of phosphorus were applied with varying degrees of increase; ficient. The phosphorus efficient cotton confirmed phosphorus inefficient soil phosphorus absorption ability. The confirmed soil phosphorus absorption ability of P-efficient was better than P-inefficient. P-efficient SPAD value higher than that of P-inefficient. Also from the aspects of physiological reflecting the optical characteristics of phosphorus efficient plant was P-efficient XLZ19.(2)Root morphology of some P cotton genotypes are affected by different P sources. At high phosphorus level P-efficient cotton on total root length and root surface area were larger. Under different phosphorus treatment, high P-efficiency root diameter of fine root length(0-0.4mm) was looger than low P-efficiency, a higher proportion of fine roots in the total root length(P<0.05). The more fine roots in the total root length is helpful to promote plant absorption of phosphorus. Rising rates of fine roots are important forms of phosphorus efficient cotton promote P absorption mechanism of change. XLZ19 has the highest percentage of fine roots.(3)Rhizosphere physiological traits of some P cotton genotypes are affected by different P sources. P-efficient cotton under low P application levels can make more P uptake than P-inefficient. Growth medium to reduce phosphorus content in the cotton rhizosphere pH also decreased, Lowering the pH of the rhizosphere of P-efficient varieties efficient amplitude was significantly higher than P-inefficient. Rhizosphere phosphatase activity of two kinds of P efficiency cotton were decreased as the phosphorus content increased in the two periods, P-efficient phosphatase activity was higher than P-inefficient.To sum up, under the sand culture and soil culture rhizosphere mechanism was different on P efficiency of cotton varieties. There is a plasticity change between root morphology and rhizosphere under different phosphorus levels. And rhizosphere phosphorus activation is the main mechanism of the change of root morphological characteristics, also is subject to the influence of phosphorus levels.