Effect Of Water And Potassium(K) Fertilizer Coupling On The Potassium Contents And Carbon And Nitrogen Metabolism Of Flue-Cured Tobacco

In this study,three levels of soil moisture and three Potassium amount were adopted in Pot experiments.The changes in the activities of nitrate reductase,glutamine synthetase,amylase,invertase,content of chlorophyll in fresh leaves;the content of soluble total sugar,reducing,starch,protein,nitrate and nitrite in curing leaves during the growth of the plants were recorded.The purpose is to study the effections of water and potassium(K) fertilizer coupling to potassium contents,every key-enzyme of carbon and nitrogen metabolism and the relationship between enzyme activity and quality formation.The results were as follows:1 Effects of water and potassium fertilizer coupling on growth and development of flue-cured tobacco.The plant height,stem thickness,maximum leaf length and maximum leaf width of tobacco plant of normal water supply and relatively humid treatment was significantly increased than drought treatment under the same potassium fertilizer treatment,and the difference bewteen relatively humid and normal water supply treatment is little.The dry matter accumulation of every part of tobacco plant was increased with soil water content rising, the difference was significant compared with among the difference soil moisture.Under the same conditions of soil moisture,the plant height,stem thickness,maximum leaf length,maximum leaf width and dry matter accumulation of tobacco plant increased with the potassium rate,but the dry matter accumulation decreased with the potassium rate rising under drought condition.2 Effects of water and potassium fertilizer coupling on potassium content of flue-cured tobacco.The potassium content of every part of flue-cured tobacco of treatments of potassium was significantly increased than without K.Under the same soil water conditions,the potassium content of flue-cured tobacco increased with the potassium rate,but the effect of applying potash fertilizer to improving the potassium content of flue-cured tobacco decreased with the soil water content rising. Under the same potassium rate conditions, the potassium content of tobacco leaf decreased with the soil water content rising, manifested as drought> normal water supply>relatively humid, it may be associated with the dry matter accumulation of tobacco plant invreased with the soil water content rising.3 Effects of water and potassium fertilizer coupling on potassium accumulated quantity and utilization rate of potassium of flue-cured tobacco.With potassium application,the potassium accumulation of flue-cured tobacco significantly increased. Under the same potassium rate conditions, the potassium accumulation of flue-cured tobacco increased with the soil water content rising, manifested as relatively humid>normal water supply> drought,it shows that it can be improve the potassium accumulation of flue-cured tobacco that improving soil water content.Under relatively humid and normal water supply condition, the potassium accumulation of flue-cured tobacco increased with increased with,but the effect of applying potash fertilizer to improving the potassium accumulation of flue-cured tobacco decreased under drought condition,and even reduced it.Under the same potassium application condition, the utilization rate of K increase with the soil moisture,and the difference was significant.Under the same soil moisture condition, the utilization rate of K of high potassium lower than medium potassium.This shows that oversupplying of potassium make the utilization rate of K decreased.4 Effects of water and potassium fertilizer coupling on key-enzyme activity of carbon and nitrogen metabolism of flue-cured tobacco.With potassium application,the activity of NR of tobacco leaf increased,but it decreased with more potassium application.The activity of NR of K fertilizer treatments lower than without potassium treatment.Under the same potassium application conditions, the activity of NR of tobacco leaf decreased on drought, and the activity of NR of tobacco leaf and root decreased on relatively humid.It shows that drought and relatively humid can inhibit the activity of NR at different degree. oversupplying of potassium make the activity of NR of root decreased. During the early growth stage, the activity of GS increased with the soil water content rising,and it maintain a high level at late growth stage under excessive soil moisture condition,this is go against the maturity of leaf because it delay the transfer from nitrogen metabolism to carbon metabolism.Oversupplying of potassium maybe decrease the activity of amylase,the effect of soil moisture to the activity of amylase is little influence. The activity of invertase reached the peak at 50 to 60 day After transplant. With potassium application,the activity of invertase increased,but the difference of the number of potassium application is little.Excessive soil moisture make the peak increased and delay the time of it appear.This increased the metabolism of carbon sequestration and turnover but decreased the the metabolism of carbon accumulation.5 Effects of water and potassium fertilizer coupling on chemical components in fresh leaves of flue-cured tobacco.Oversupplying of potassium, drought and relatively humid make total sugar and reducing sugar content of tobacco leaf decreased.Starch content of tobacco leaf increased with soil moisture and decreased with K application rate(except of drought). With potassium application,the protein content of tobacco leaf increased during the early growth stage of tobacco plant.Excessive soil moisture decreased the protein content of tobacco leaf.Under drought,the protein content decreased at the early growth stage but increased at late growth stage. Nitrate content of tobacco leaf decreased with soil moisture,the effect of soil moisture on decrease nitrate content to tobacco leaf is more than potassium application.This shows that Water Supply is useful for decreaseing nitrate content of tobacco leaf.Excessive soil moisture and drought increased the content of nitrites of tobacco leaf, especially at late growth stage under relatively humid.6 Effects of water and potassium fertilizer coupling on neutral aroma components of flue-cured tobacco.Under the same soil moisture condition, potassium application can obviously increased the contents of cembranenoids,carotenoids,neophyteadiene and the total of neutral aroma components.The contents of cembranenoids and phenylalanines decreased with the potassium rate.Under without potassium condition,the contents of neophytadiene decreased with the soil water content rising, the minimum content is the normal water supply treatments under medium potassium, and the maximum content is the relatively humid treatments under high potassium. The contents of phenylalanine and the total of neutral aroma components decreased under drought and relatively humid,and the total of neutral aroma components decreased with the potassium application. The contents of cembranenoids decreased with soil water content rising.Under potassium application condition,the difference of the content of browing reaction products manifested as normal water supply> drought> relatively humid, but carotenoids manifested as normal water supply> relatively humid > drought. Browing reaction products decreased with soil water content rising in the case of no-potassium application.