| Longjiang tobacco area is the representative tobacco cultivation and planting area in Northeast China.However,due to the influence of soil,climate and other environmental factors,the tobacco leaves planted and harvested in Longjiang tobacco area always have the problem of low potassium ion concentration,which makes the quality of flue-cured tobacco unable to be improved.In order to solve the above problems,this study used Non-invasive Micro-test Technology(NMT),real-time quantitative PCR(qRT-PCR)and atomic absorption spectrophotometry to explore the flow and accumulation of potassium ions in flue-cured tobacco in pot experiment.At the same time,the differences of growth agronomic traits,photosynthetic rate and chemical composition accumulation of seven flue-cured tobacco varieties were compared by field experiment,and factor analysis was used to evaluate the flue-cured tobacco varieties,in order to provide some theoretical basis for improving the quality of flue-cured tobacco in key tobacco areas of Heilongjiang province.The main findings of the study are as follows:1.The expressions of potassium ion transport related genes NtKC1,NTORK1 and NtHAK1 were detected by qRT-PCR,combined with the results of NMT technique,we found that the potassium ion flow of LJ0520 was absorbed in both nitrate and ammonium nitrogen sources,and the expression level of the inner channel gene NtKC1 was relatively higher than that of the outer channel gene NTORK1.Among them,the potassium ion absorption capacity of this variety is stronger under the condition of ammonium nitrogen source.The potassium ion absorption of LJ911 showed an opposite trend under two different nitrogen sources.The root of LJ911 could absorb potassium ions well under nitrate nitrogen source conditions,and the expression of NtKCl gene was relatively higher than that of NTORK1 gene.However,in the condition of ammonium nitrogen source,potassium ion excretion appeared in the root,and the expression level of NtKC1 gene was relatively lower than that of NTORK1 gene.Therefore,it was speculated that the nitrate nitrogen source form of LJ911 and ammonium nitrogen source form of LJ0520 could better promote the absorption of potassium ions by the two flue-cured tobacco.2.The results of the determination of potassium ion content in flue-cured tobacco leaves showed that the potassium ion accumulation of LJ911 and LJ0520 was affected by the form of nitrogen source in nutrient solution and the presence of potassium ion.When the content of potassium ions in nutrient solution was sufficient,the nitrate nitrogen treatment group was more conducive to the accumulation of potassium ions in the two flue-cured tobacco.When potassium ions were lacking in nutrient solution,LJ0520 leaves had a stronger potassium accumulation ability than LJ911 leaves.3.The analysis of photosynthetic rate and growth characteristics of seven flue-cured tobacco varieties showed that LJ0520 was better than other varieties in photosynthetic rate.In terms of growth characteristics,the plant size of LJ911 and LJ986 was moderate,and the root growth was relatively vigorous.LJ982 tobacco plant is relatively short,but its leaf growth is very dense.LJ0520 was taller with larger leaves and stout stalks,but its root growth was relatively weak.LJ237 had a strong growth potential,and the plant height and leaf size were relatively good.The growth of K326 plant was weak above ground.LY2829 plants were relatively tall and stout,and the leaf area coefficient was relatively high in the later stage.4.Through the determination of the contents of potassium ion,chloride ion,total nitrogen and total phosphorus,it was found that three varieties LJ0520,LJ237 and LY2829 accumulated more total nitrogen and total phosphorus at rosette stage,which provided sufficient nutrients for their rapid growth.The potassium ion,chloride ion,nicotine,etc.of cured tobacco leaves were measured,and the ratio of related indexes was calculated.The chemical composition was evaluated comprehensively by factor analysis.It was found that the central leaves of 7 flue-cured tobacco varieties had higher scores.It was found that the lower leaves of LJ237,the middle leaves of LJ982 and the middle leaves of LY2829 showed relatively good chemical quality by combining the ranking of the third common factor representing potassium ion content,which could provide some theoretical basis for the selection of potassium-rich varieties of flue-cured tobacco. |
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