Study On The Phenotypic Differences And Nutritional Characteristics In Different Genotypes Of Potassium Of Flue-cured Tobacco (Strains)

The low potassium content in tobacco leaves has constantly restricted the quality of tobacco in our country. As the potassium resource scarcity and the poor utilization efficiency of potash fertilizer, breeding the high K genotypes of flue-cured tobacco is an efficient way to enhance the potassium content in tobacco. The experiment applied the sand cultivate way, tested materials are 5 flue-cured tobacco named K2,K3,K5,K7,K9 which,imported K-rich gene and the check sample is K326. The materials was cultivated under the two potassium levels,0.6mmol/L and 6.0mmol/L, the growth characteristics of different genotypes tobacco and the absorption of potassium in soil solution, accumulation, distribution and the differences between the K-rich potassium genotypes and K326 in absorbing and utilization efficiency were studied. The main results are as follows:1. Under all potassium levels, the plant height, leaf area, leaf aspect ratio and leaf spacing of high-K genotypes tobacco are all greater than K326, in which K7 and K9 perform best, K2 and K5 ranking second,and then the K3. Meanwhile, the amount of dry matter of high-K genotypes tobacco is also higher than K326, among which K5, K7 and K9 are comparatively higher. It showed that the high-K genotype tobacco having an advantage than K326 on the agronomic characteristics, and the dry mass is increased along with the phenotype advantages.2. Influenced by dry mass and potassium accumulation intensity, the main range of variation on potassium content of tobacco leaves of different potassium efficient genotypes tobacco are different.25 days after transplanting, compared with the high potassium level, K-rich potassium genotypes decline more than K236 under the low potassium level, the range is between 83.81% to 88.83%.45 days'after transplanting, the declining of accumulation of potassium in the K-rich potassium genotypes to the exclusion of K5 are slower than K326, decreased by 89.62% to 92.85%, and the difference is unsignificant. Therefore, with the growth and develepment of tobacco plant, K5 can keep the high potassium level 45 days after transplanting, which helps to improve the cointent of potassium in tobacco.. On the conditions of low K, the accumulation of potassium in the K-rich potassium genotypes is more than K326 25 days after transplanting, moreover, the accumulation of potassium in K2 and K7 is obviously less than K326 25 days to 45 days after transplanting. Comparing in transplanting 45 days with 25 days, the accumulation of potassium in K326, K2 and K7 is declined, and the decreasing extent of K2 and K7 is less than K326, and that the accumulation of potassium in K3,K5 and K9 is increased. It shows that K3,K5 and K9 have a good ability and potential of absorbing potassium. 3. On the condition of high K, potassium efficient genotypes tobacco have higher root activity, and K9 is the best. After 45 days'transplanting,on the low potassium levels, the root activity of different genotypes tobacco is higher than the high potassium levels, and the root volume, root total and active absorption area of different genotypes tobacco are lower than the high potassium levels. After 45 days'transplanting on the low potassium levels, the root volume and root activity of different genotypes tobacco is lower than the high potassium levels, and K9 got larger root total and active absorption area, which is respectively larger by 9.22% and 70.08% than the high potassium level.K2 and K7 got larger root active absorption area, by 15.87% and 75.90% respectively. It indicates that K2,K7 and K9 possess characteristic of root morphology which is beneficial for the absorption and accumulation of potassium in the low potassium environment in latter growth period.4. Compared high-K genotypes of flue-cured tobacco with K326, the root of the former has a bigger Vmax value, the smaller Km and Cmin value. It indicated that the potassium efficient genotype have the higher affinity to potassium, it can absorb and utilize patassium under any potassium level. In different high-K genotypes of flue-cured tobacco, K7 and K9 have the biggest Vmax value, the highest affinity to potassium (Km) and the lowest concentration absorption of potassium the smallest (Cmin), secondly, the K2,K5. and K3 are minimal.So,it indicated that the absorbing dynamics of potassium of potassium efficient genotypes tobacco is distinct to screen high potassium genotypes flue-cured tobacco.