| In order to learn the differences and its mechanism in low-K~+-tolerance of different variety of potato, the experiment of sand culture was carried out by planting different genetype potatoes, according to the measurement of the yield of different potato varieties under the two processing: potassium stress and the comparison, screening result showed that the following were high potassium efficiency varieties: N6-22, zhongnongâ…§-1, J-Aba, Yihongpi, 971-12 and Zhongnongâ…§-3; Zhongnongâ…§-2, Gaoyuan 7, Mira, 901-1-26, Yihongpi, Chuanyu 5 were K~+ deficit non-tolerant potato varieties. Then we made use of the above listed typical high potassium efficiency material N6-22, K~+ deficit tolerant potato variety Zhongnongâ…§-2 and the middle type Hezuo 88 by sand culture(0,5,10mmol/L, K~+)and water culture(0,5,10,15,20mmol/L, K~+). The dry material accumulation and part of the physiology target which related to K during the five growing period were tested to analysis different K~+ nutrition varieties' absorption, transportation, and using.The result showed: Under potassium stress, per plant yield of N6-22 was extremely positive higher than the average, zhongnongâ…§-1, J-Aba, Yihongpi, 971-12 and Zhongnongâ…§-3 were positive higher than the average, so the above six are high potassium efficiency varieties; the six low-potassium tolerance strains were Zhongnong-2, Gaoyuan 7, Mira, 901-1-26, Yihongpi, Chuanyu 5, which had a more than 95% relative yield under potassium stress. The study showed that K~+ nutrition has a positive effect on tuber yield, water content and starch content, potassium stress positive decreased tuber yield and water content, but the effect on starch content depended on the varieties. At the same time, potassium stress lead to the decreasing oftuber yield, this is mainly related to the decreasing of water content in tuber.With the increase of the K~+ concentration, the accumulation of dry materials is improved, the accumulation peak of each variety is 90 days after sowing, from the whole growing period, the accumulation speed had a"slow-fast-slow""S"type tendency. The high potassium efficiency variety N6-22 had a higher accumulation in dry materials, and decreased slowly during the latter growing period, benefited to further accumulation, to the contrary, Zhongnongâ…§-2 showed a lower accumulation of the root materials, the difference between concentration of K~+ were not positive. The balance of dry materials in different K~+ concentration of the two variety above appeared after 70-90 days growing, while Hezuo 88 was delayed to 90-120 days, it suggested potassium stress has an more serious effect on Hezuo 88.The K~+ content in root, stem, leaf were much higher after 30 days growing, low potassium stress varieties Zhongnongâ…§-2 had a lower K~+ content in root, but higher in tuber, and it released K~+ in the later growing period; N6-22's K~+ content in tuber decreased slow in the later time, meanwhile extremely positive higher than the other two, thus, it could promise the transportation of carbohydrate, the K~+ content in tuber was low, but the efficient for use is high, and it had a higher water content although the difference were not positive between the water content in varies of K~+ concentrations. From the organic acids in root exudates, Zhongnongâ…§-2 higher than the other two, oxalic acid was more, the ability of K~+ releasing in root was strong in any K~+ concentrations, which might be the main mechanism of low-potassium tolerance. To the conclusion, the study inference that Zhongnongâ…§-2 has a strong ability to absorb K~+, the K~+ in body distributed in leaf, stem and tuber, relatively low in root. N6-22 balance the transportation and accumulation of photosynthesis product by high K~+ content in stem and high K~+ efficiency for use in tuber. |
