| Potassium is necessary for the growth of tobacco, plays an important role in improving the tobacco burning, aroma and taste, and security. Potassium content is one of the main indicators to evaluate the quality of tobacco. Study for potassium absorption, distribution and other characteristics in potassium efficient genotypes of flue-cured tobacco are important to breeding and utilization of the high-potassium tobacco. The differences in potassium accumulation of leaf at different growth stages between two new lines of flue-cured tobacco with potassium efficient genotypes and K326was researched. Migration and Distribution of potassium between different organizations of leaf during the maturity and modulation, the impact of temperature in modulation to the distribution of potassium in leaf were researched also. Based on conditions described in the article, we got the following conclusions:(1) Potassium content in leaf of two high-K lines GK2and GK8were significantly higher than that of K326during the seedling to the end of modulation; Differences can be finding between GK2and GK8. Potassium content of GK2were significantly higher than GK8from the seedling stage to maturity, especially in rosette and maturity stage, the difference reached a significant level. There was no significant difference after the modulation.(2) Periodic migration of potassium occurred between the leaves and stems from06:00to20:00. The regular pattern of the migration between genotypes is basically the same. The relative potassium content of all parts of the leaves reached a peak around18:00, around06:00and20:00were lower.(3) There is also the migration of potassium between the various organizations of leaves. The phenomenon that potassium migrates from the veins to the mesophyll and the leaf margin part is the most obvious during the08:00-12:00and16:00-18:00, but not obvious during12:00to16:00. Potassium begins to return from various parts of the leaf to the leaf veins and stems after18:00. Compared with K326, the migration phenomenon of potassium of GK2is more obvious, and the range of the change in potassium content is wider.(4) Transport rate of potassium in the leaves is differences between the different times, different parts, as well as between the different genotypes. Both the max rate and the average rate of GK2were higher than that of K326. The peak period of potassium translation in upper leaf of GK2and K326occurred during the06:00-08:00and16:00-20:00, and occurred mainly in8:00-12:00in bottom leaf.(5) Potassium content in various issue of leaves changed during the modulation, especially at the first96hours. The percent of potassium in mesophyll and margin part of leaf both in GK2and GK8were raised when the modulation finished, but the percent of potassium in veins declined. The opposite phenomenon occurred in K326.(6) Temperature has a significant impact on the migration of potassium in tobacco leaf when turning yellow in the modulation process. The tendency of the potassium migration in GK2and GK8is accorded with that in K326. With the raising of the temperature in turning-yellow stage, potassium content of veins declined, potassium of mesophyll and margin part of leaf increased. The order of potassium content in all parts of leaf is:GK2>GK8>k326; and in all genotypes is:vein>mesophyll>margin part. |
