中文摘要：

钾是植物生长必须的重要矿质元素,提高作物对钾的吸收是提高作物产量的重要途径。本研究以前期遗传转化披碱草EdHP1（H＋-pyrophosphatase）基因的烟草为材料,在低钾处理条件下比较了转基因烟草和野生型烟草的生理特性。结果显示,在低钾条件下,野生型烟草体内K＋积累量只相当于转基因烟草的62.9%。野生型烟草的总根长、总根表面积、总根体积明显低于转基因烟草（P〈0.05）,分别为转基因烟草的72.9%、68.1%和60.6%。在不同直径根系（0.5～2.0、2.5～4.5、〉4.5mm分别为细根、中等根和粗根）中,细根发育差异最大,野生型烟草为转基因烟草的72.9%。低钾条件下,转基因烟草根系活力是野生型烟草的1.2倍,野生型烟草根系焦磷酸化酶活力相当于转基因烟草的46.4%,根部游离IAA含量相当于转基因烟草的66.2%。通过非损伤方法测定根部K＋和H＋流速结果显示,在根系表面积相似情况下,低钾条件下野生型烟草外排钾速率显著高于转基因烟草,而氢离子外排速率显著低于转基因烟草。综上所述,发达的根系和较高的K＋转运体活性综合作用显著提高了转基因烟草根部对K＋的吸收。

英文摘要：

Potassium is necessary for plant growth and enhancing uptake of potassium is important to improve crop yield, In this study, previous transgenic tobacco transformed with Elymus dahuricus EdHP1 （H^＋-pyrophosphatase） was used to compare the physiological characteristics between transgenic tobacco and wild type tobacco. The results showed that under starvation of potassium, the content of K^＋ accumulated in wild-type tobacco was 62.9% of that in transgenic tobacco, and the total root length, total root surface area, and total root volume in wild type tobacco were observably lower than those in transgenic tobacco （P〈0.05）, with the decrease of 72.9%, 68.1%, and 60.6%, respectively. In addition, in different root systems of fine roots （diameter=-0.5-2.0 mm）, middle roots （diameter = 2.5-4.0 ram） and coarse roots （diameter〉4.5 mm）, fine roots were biggest different between transgenic and wild type tobacco which fine roots were 72.9% of those in transgenic tobacco. The activity of root system in transgenic tobacco was 1.2 times as high as that in wild type tobacco. The activity of H^＋-pyrophosphatase and the content of free IAA in wide-type tobacco were only 46.4% and 66.2% of those in transgenic tobacco respectively. The results of non-destructive ion flux measurement showed that under starvation of potassium the efflux of K^＋ from wild type tobacco was observably higher than that from transgenic tobacco, but inverse result was found efflux of H^＋ with similarly total root surface area of transgenic tobacco and wild type tobacco. Two physiological mechanisms containing well-developed root system and higher activity of K^＋ transporters enhanced uptake of potassium in EdHP1 transgenic tobacco plants.