【作者】 张纪涛；

【导师】 王林权；

【作者基本信息】 西北农林科技大学 ， 植物营养学， 2011， 硕士

【摘要】 为探究不同温度型小麦K⁺吸收动力学特征及其盐胁迫效应,进一步揭示不同温度型小麦幼苗的耐盐机制,丰富温度型理论,本文用NR9405（暖型）、小偃六号（中间型）、陕229和RB6（冷型）等四种不同温度型作为试验材料,采用浓度梯度法研究了不同温度型小麦幼苗（14d）K⁺的吸收动力学特征,并结合药理学方法探讨了高亲和与低亲和的K⁺吸收系统在不同温度型小麦幼苗K⁺和Na⁺吸收累积中的作用。得到以下主要结论:1.不同温度型小麦幼苗K⁺吸收动力学特征在0⁵0mmol·L^-1的K⁺浓度范围内,4种不同温度型小麦幼苗K⁺吸收速率随浓度的增加而增大,可分为高亲和吸收(0¹mmol·L^-1)和低亲和吸收(1⁵0mmol·L^-1)等两个过程,二者均可用米氏方程描述。高亲和吸收过程中,暖型小麦的亲和系数Km和最大吸收速率Imax分别为0.332mmol·L^-1和33.57μmol·h-1·g-1RDW,小于两种冷型小麦的0.430⁰.432 mmol·L^-1和42.46⁴3.13μmol·h-1·g-1RDW,中间型小偃六号则介于二者之间,Km和Imax分别为0.353 mmol·L^-1和35.38μmol·h-1·g-1RDW。NR9405的养分离子流入系数α[K⁺]值最大,为101.02,小偃六号次之,为100.36,陕229和RB6较小,分别为98.86和99.84。说明暖型小麦对K⁺的高亲和力是K⁺吸收能力强的重要原因之一。NR9405、小偃六号、陕229和RB6等四种小麦幼苗低亲和吸收(1⁵0mmol·L^-1)的特征值分别为:Imax值分别为213.33、185.73、197.93和253.37μmol·h-1·g-1RDW,而Km为30.35、20.90、21.22和30.38mmol·L^-1,α[K⁺]值分别为7.03、8.89、9.33和8.31;NR9405和RB6的Imax值较大,Km较高,而小偃6号和陕229则相反,Imax值较小,Km较低。陕229的α[K⁺]最高,NR9405最低。抑制低亲和吸收系统后,NR9405和小偃6号的Km值不受影响,Imax值和α[K⁺]值增大;而陕229和RB6的Km值和Imax值均增大,α[K⁺]值变化不大。说明暖型小麦的高亲和吸收系统与K⁺的亲和力不受低亲和系统影响,而抑制低亲和吸收系统可以增加其吸收容量和吸钾能力;而抑制冷型小麦的低亲和系统会降低冷型小麦高亲和系统对钾的亲和力。抑制高亲和吸收系统后,小麦幼苗的低亲和吸收特征值Imax和Km均有所增加,Imax值在314³90μmol·h-1·g-1RDW之间,冷型小麦的增幅大于暖型小麦。Km在29⁵5mmol·L^-1之间;冷型小麦增幅也大于暖型小麦。说明抑制高亲和吸收系统后,降低了幼苗对K⁺的亲和力,但增加了最大吸收容量。2. Na⁺对不同温度型小麦幼苗K⁺高亲和吸收动力学特征的影响50¹00mmol·L^-1的Na⁺存在降低了K⁺高亲和吸收速率,吸收动力学过程仍然符合米氏方程。50¹00mmol·L^-1的Na⁺显著降低了Imax和α[K⁺]值,冷型小麦的降幅大于暖型小麦;暖型小麦NR9405和中间型小偃六号的Km值不受盐浓度的影响;而在100mmol·L^-1的Na⁺浓度时冷型小麦的Km值降低了20%³0%。这说明冷型小麦对Na⁺胁迫响应的反应较暖型小麦敏感。50¹00mmol·L^-1的Na⁺胁迫下冷型小麦的α[K⁺]均低于其他两种小麦,即K⁺吸收能力较低,这可能是冷型小麦耐盐能力较低的原因之一。3. Na⁺对不同温度型小麦幼苗K⁺低亲和吸收动力学特征的影响100¹50mmol·L^-1的Na⁺存在下,K⁺低亲和吸收(1⁵0mmol·L^-1)速率降低,且其吸收动力学过程不符合米氏方程,只能用线性方程描述;可以划分为1¹5和15⁵0mmol·L^-1等两个吸收阶段。100¹50mmol·L^-1的Na⁺胁迫引起K⁺的外流,在较低的K⁺(约1³ mmol·L^-1)浓度下出现净流失。4. Na⁺对不同温度型小麦幼苗生长与离子吸收的影响NR9405的地上部K⁺累积能力强于RB6。随着介质中Na⁺的增加地上部K⁺含量逐渐下降。在无盐环境中,两个小麦基因型的盐分含量没有差异,盐胁迫下随Na⁺浓度的增大,地上部Na⁺含量和细胞浓度都逐渐增加,RB6的累积量大于NR9405。K⁺对地上部Na⁺含量的影响因品种和盐浓度不同而异,在100mmol·L^-1盐浓度下,K⁺可明显降低RB6地上部的Na⁺累积量。地上部Na⁺/K⁺含量比与细胞内Na⁺/K⁺离子浓度比与地上部生长速率呈显著负相关,可以作为耐盐评价的指标。更多还原

【Abstract】 In order to enrich the tempreture type theory and reveal the salt tolerance mechanism of wheat, we studied the effect of Na⁺ on K⁺ high affinity transporter systems（HATs） and low affinity transporter systems （LATs） absorption kinetic characteristics of wheat seedlings with different canopy temperatures: NR9405 （warm type）,Xiaoyan NO.6（middle type）,RB6 and Shan229（cold types）. As well as we studied the effect of Na⁺ on shoot growth and ion accumulation of the 4 types wheat seedlings. The main research results as follows:1. In the range of 0⁵0 mmol·L^-1 K⁺, K⁺ absorption velocity of the 4 different type wheats increased with the increasing concentration. It can be divided into two phases, high affinity transport(HAT,0¹mmol·L^-1) and low affinity transport (LAT,1⁵0mmol·L^-1). both of the uptake process can be described by Michaelis-Menten equation.For K⁺-HAT, Km and Imax of warm type wheat was 0.332mmol·L^-1 and 33.57μmol·h-1·g-1RDW that less than that of the cold type, Shaan229 and RB6, which were 0.430⁰.432 mmol·L^-1 and 42.46⁴3.13μmol·h-1·g-1RDW, and that of the middle type XiaoyanNO.6 is 0.353 mmol·L^-1 and 35.38μmol·h-1·g-1RDW, which is between the two types.α[K⁺]（coefficient of K⁺ influx） of the 4 types, NR9405 is 101.02, XiaoyanNO.6 is 100.36, Shaan229 and RB6 is 98.86 and 99.84. It revealed that high K⁺ affinity of warm type wheat is one reason why it had stronger K uptake capacity .For K⁺-LAT, Imax of NR9405, XiaoyanNO.6, RB6, Shaan229 wheats were 213.33、185.73、197.93 and 253.37μmol·h-1·g-1RDW, Km were 30.35、20.90、21.22 and 30.38mmol·L^-1,α[K⁺] were 7.03、8.89、9.33 and 8.31, respectively. Imax and Km of NR9405 and RB6 were higher, while XiaoyanNO.6 and Shaan229 with lower Imax and Km.α[K⁺] of Shaan229 is maximum, and NR9405 is minimum.When inhibited low affinity systems, Km was not affected and Imax andα[K⁺] increased in NR9405 and XiaoyanNO.6, while Km and Imax increased,α[K⁺] almost not changed in Shaan229 and RB6. It means that inhibited LATs not affect K⁺ affinity with HAT, but increased K⁺ absorption capacity in warm type wheat. But K⁺ affinity with HATs decreased in cold type wheat,when inhibited the LATs.When inhibited HATs,character parameters of LATs increased.Imax of 4 wheats in 314³90μmol·h-1·g-1RDW,Km in 29⁵5mmol·L^-1. Imax and Km of cold type increased more than warm type.It mean that K⁺ affinity of LATs of 4 wheats decreased and increased K⁺absorption capacity ,when inhibited HATs.2. K⁺ high affinity(0¹mmol·L^-1) absorption velocity curve could be decreased by the Michaelich-Menten under 10¹00 mmol·L^-1 Na⁺.The Imax andα[K⁺] of 4 wheats decreased by the Na⁺ exist,effect of Na⁺ on Imax andα[K⁺] of cold type wheat is relatively serious.Km of NR9405 and XiaoyanNO.6 almost uneffected by salt stress, the Km of cold type wheats decreased by 20%³0% by 100mmol·L^-1 Na⁺.The result indicated that reaction of cold type is sensitive to salt stress.Under 50¹00mmol·L^-1 Na⁺,α[K⁺] of cold type wheats lower than NR9405 and XiaoyanNO.6,it mean than K⁺ absorption capacity of cold type is lower,it is reason that salt tolerance of cold type lower than warm and middle types.3. The relationship between K⁺ low affinity absorption velocity and concentration in the solution can be described by line equation, within 1⁵0 mmol·L^-1 K⁺ concentration, and it divided into two phases , 1¹5 and 15⁵0mmol·L^-1, which described by line equation with different slopes.LATs K⁺ absorption velocity decreased as the existence of Na⁺ (100¹50 mmol·L^-1 ).Thus, the existence of Na⁺ make K⁺ flow out seriously, even with negative net absorption under lower K⁺ concentration(1³mmol·L^-1).4. K⁺ absorption capacity of NR9405 stronger than RB6.K⁺ content of shoot of the both wheat seedlings decreased with increasing Na⁺ concentration in solution.Na⁺ content of shoot not different between the both wheat genotypes seedlings.Na⁺ content and concentration of shoot of the both wheat seedlings increased with the increasing Na⁺(0¹50mmol·L^-1) concentration in the solution under every K⁺ contration,and Na⁺ accumulation content of RB6 higer than NR9405.Different cultivars and salt contration due to the effect of K⁺ on Na⁺ content of shoot were different,this effect were significant,while NR9405 under 150mmol·L^-1 Na⁺ and RB6 under 100¹50mmol·L^-1 Na⁺. The content ratio of Na⁺/K⁺ or cell concentration ratio in shoot was significantly related with the growth velocity in different treatments, thus, it was a reliable index to identify the salt resistence.更多还原