Influences Of Density And Potassium Interaction On Physio-ecological Indicators And Quality Of Flue-cured Tobacco In Yanbian

Abstract: During 2009 and 2010,a field experiment was employed to study the changes of agronomic characteristics, enzyme activity in carbon and nitrogen and photosynthetic characteristics and quality of flue-cured tobacco under planting density,K application and their interactions using the tobacco cultivar Jiyan No.9(local cultivars) in Yanminghu town in Dunhua. The results was followed:1. The study of agronomic characteristicsWith the increase of planting density, leaf area and number per plant, length,width and area of different parts of tobacco plants showed the tendency of decreased. With the increase of potassium application rate, length,width and area of different parts of tobacco plants showed the tendency of ascend. Planting density and K application interaction certainly affected the leaf length,width and area, the treatment A3B3 which was planting density 13500 trees/ha and K application 328.5 Kg/ha was too higher.It indicated that adding potassium application could improve the tobacco agronomic characteristics and tobacco production in low planting density.2. The study of chromoplast pigment in flue-cured tobacco leafThere was an obvious influence on chromoplast pigment contents during the interactions of planting density and potassium application rate, the treatment A2B3 (planting density 15100 trees/ha and K application 328.5 Kg/ha)was better.The results showed that treatment A2B3 not only significantly increased chromoplast pigment contents and created favourable condition for Photosynthesis,but promoted the maturity of leaf of flue-cured tobacco.3. The study of key enzymes activities of C and N Metabolism in flue-cured tobacco leafThere was an obvious influence on C and N Metabolism during the interactions of planting density and potassium application rate, the treatment A2B3 (planting density 15100 trees/ha and K application 328.5 Kg/ha)was superor. It showed that reasonable planting density and adding potassium application could improve nitratase activity and nitrogen metabolism, inceease transferas activity and nitrogen metabolism in flue-cured tobacco development prometaphase, not raise transferas activity in the late development stage, remarkably enhance amylase activity at the late development stage of flue-cured tobacco, enhanced carbon metabolism.4. The study of photosynthetic characteristics4.1. The study of photosynthetic characteristics on different growth periodThe study proved that applying potash fertilizer increased capture volume and conversion efficiency of light, ultimately promoted Pn, was beneficial to substance accumulation of assimilation product in the reasonable planting density.All photosynthetic indexs of treatment A2B3 (planting density 15100 trees/ha and K application 328.5 Kg/ha) among nine treatments were the biggest.4.2. Effects of planting density on diurnal changes of photosynthetic characteristics in flue-cured tobaccoThe results showed that the net photosynthetic rates (Pn), stomatal conductance(Gs) , transpiration rates (Tr), leaf temperature (TL) and air temperature (Ta) diurnal changes of the three densities all appeared as single peak curves, the majority of peaks presented to 11:00 or 13:00, and they all didn't show midday depression; Higher or lower range planting density decreased photosynthesis, the structure of planting density 15100 trees/ha showed that Pn was too higher and photosynthetic capacity was too stronger was rational;It was Gs that affected the changes of Pn among the physiological factors , and PAR played very important roles in the hanges of Pn among the ecological factors; Perhaps mu-ch rainy of Yanbian provided enough water for tobacco which was the main cause of no midday depression phenomenon.5. The study of chemical components in flue-cured tobaccoThe results showed that: In planting density A2 (15100 trees/ha) and K application B3 (328.5 Kg/ha) conditions, K+ was absorbed better than other treatment, and the content of total sugar, reducing sugars, protein in upper leaves were suitable; In planting density A3 (13500 trees/ha) and K application B3 (328.5 Kg/ha) conditions, the content of total sugar and reducing sugars in lower and middle leaves were suitable, and the chemical quality index is more reasonable; But only in planting density A2 (15100 trees/ha) and K application B2 (276.45 Kg/ha) conditions, the lower leaves had appropriate protein contents. All the results suggested that structure of treatment A2B3 and A3B3 which were planting density 15100 trees/ha and 13500 trees/ha respectively combination with K application 328.5 Kg/ha on the quality of flue-cured tobacco leaf were reasonable, and the tobacco quality was better.6. The study of neutral aroma components contents in flue-cured tobacco Results showed that: Both of the treatments, namely planting density and K application, and their interactions extremely significantly affected the contents of neutral aroma components in post-cured tobacco leaf. With the increase of planting density and the increase of potassium application rate, the contents of products degraded by carotene, products of browing reaction, products degraded by cembranes, neophytadiene and neutral aroma components increased and showed the tendency of decreased first and ascend later; With the increase of planting density and potassium application rate, the contents of phenylalanine showed an earlier raised and later decreased state. All the results suggested that structure of treatment A2B3 which was planting density 15100 trees/ha and K application 328.5 Kg/ha on the quality of flue-cured tobacco leaf was reasonable and were higher on the potassium and neutral aroma components contents of the flue-cured.