Study On Response Of Potato To Different Phpsphoric Consisitencies And Mechanism Of Phosphoric Efficiency

To explore the difference and cause of potato's phosphoric nutrient use efficiency under varying phosphoric consistencies, this test is based on 24 potato varieties, through sand culture, with 1/2MS nutrient solution of low phosphorus (0 mmol·L^-1), normal phosphorus (0.625 mmol·L^-1) and high phosphorus (1.25 mmol·L^-1). On observing the differences of potato's yield, shape and physiology in its maturity, the representative varieties could be selected, and its phosphoric nutrient performance could be researched through two aspects of root exudates and phosphorus absorption kinetics.(1) With the pressure of low phosphorus, the yield of Chuanyu 4, J-dabai, N6-22, Chuanyin 1, Chuanyu 5, Epoka, 3-15-3, 3-10-2, 3-8-1 are remarkably higher than the average value, which belongs to efficient variety of phosphorus. Yet there's no significant shows on their root shoot ratio and phosphoric utility ratio. Except 3-15-3, those varieties' over-ground parts and roots are not obviously stronger than others. In the same condition of low phosphorus, 3-17 gains no tubers while the output of Liangshu97 is listed in the last but one.Under the condition of normal phosphorus does, the yield of N6-22 and Epoka are obviously higher than those of others. 3-17's output says to be the tail-ender, and Liangshu97 still keeps in a badly low level than average value. In contrast, in the condition of high phosphorus, the output of Liangshu97 is rather higher than others', while the difference of 3-17's average outputs is not obvious.The path analysis of yeild under 3 phosphoric consistencies shows that, the linear relationship of regression equation is obvious but remaining path coefficient is big, what evidence that the bigger factor influences starch content are not yet to be found. In 3 phosphoric consistencies, the biggest factor influences the output is the absolute water content of potato tubers. Under the pressure of low phosphorus, those other big factors influence yield including: root length, phosphorus content of over-ground part, and phosphorus content of sand. Above last 2 factors will raise an adverse effect on yield. In the condition of normal phosphorus, those other big factors influence yield including: root fresh weight, phosphorus content of tubers, and phosphorus of sand. Above last 2 factors will raise an adverse effect on yield. Moreover, when in high phosphorus, those other big factors influence yield including: phosphorus content of over-ground part, fresh weight of over-ground part, and phosphorus content of tubers. Above fore 2 factors will raise an adverse effect on yield.The path analysis of starch under 3 phosphoric consistencies shows that, the linear relationship of regression equation is not obvious and remaining path coefficient is big, what evidence that the biggest factor influences starch content are not yet to be found. (2) From sand culture test results, select those representative varieties to process aquaculture test: phosphoric efficient variety Epoka, low phosphorus sensitive variety3-17 and medium variety Hezuo88. From the organic acid secreted by Epoka, 3-17和Hezuo 88 in 2 phosphoric consistencies(0 mmol·L^-1, 0. 625 mmol·L^-1), it could be found that Epoka produces oxalic acid, citric acid and D-malic acid with the pressure of low phosphorus, while only produces oxalic acid under normal phosphorus condition; 3-17 only produces oxalic acid under the condition of low phosphorus pressure, while it could produce oxalic acid, citric acid and D-malic acid in normal phosphorus condition. Nowever the sums of secretion volume in 2 phosphoric consistencies are both lower than those of Epoka; Hezuo 88 will produce oxalic acid, citric acid and D-malic acid in both 2 phosphoric consistencies, and the sums of its secretion volume are higher than those of other 2 varieties.From the activation ability of the organic acid to ophorus, which is secreted by Epoka, 3-17 and Hezuo 88 in 2 phosphoric consistencies(0 mmol·L^-1, 0. 625 mmol·L^-1), it could be found: In low phosphorus consistence, the activation ability size down is Epoka＞Hezuo 88＞3-17, and the gaps of each two reach to a extreme remarkable level; in normal phosphorus, the activation ability of Epoka is extreme higher than those of Hezuo 88 and 3-17's, while the activation ability of Hezuo 88's is obvious higher than 3-17 but not reach to extreme level.(3) Comparing in normal phosphorus level, each variety's I_max and K_m values are increased greatly under the condition of low phosphorus pressure. In low phosphorus, the I_max value size is: 3-17＞Epoka＞Hezuo 88, K_m value size is 3-17＞Hezuo 88＞Epoka, C_min value size is 3-17＞Hezuo 88＞Epoka. In normal phosphorus, the I_max value size is: Epoka＞3-17＞Hezuo 88, K_m value size is Hezuo 88＞3-17＞Epoka, C_min value size is 3-17＞Epoka＞Hezuo 88. Low C_min of Epoka in low phosphorus is the important reason of high efficiency of phosphorus use.