The Dynamic Study Of Potassium Accumulation And Distribution On Flue-cured Tobacco At Different Levels Of Potassium

The pot experiments and solution culture experiments were conducted using tobacco cultivar K326 as the experiment material on the Henan Agricultural University campus between 2005 and 2006.The effects of the dry matter accumulation and potassium content,potassium accumulation of fue-cured tobacco and other chemical composition and physical characteristics of the different organs and different growth period at different levels of potassium treatments were preliminary studied.We also discussed the potassium loss channels of flue-cured tobacco.The results are summarized as follows:1 The effects of the dry matter accumulation of different organs and different growth period at different levels of potassium treatments of flue-cured tobaccoThe total dry matter weight had been on the in increase of the low,middle and high potassium level treatments with the growth period extended after transplanting of flue-cured tobacco.The dry weight of phloem,xylem,leaves and roots had increased in the whole growth period of flue-cured tobacco.The dry weight of different organs were the leaves>the stern>the roots at harvest time(90 days after transplanting).In early days after transplanting, the plant dry weight was high potassium level> middle potassium level> low potassium level.It proved that increase the amount of potassium fertilizer can increase the tobacco plant dry matter,but 75 days after transplantation,the role of the high potassium level increase the tobacco plant dry weight has been greatly diminished.2 The effects of the potassium content and accumulation of different organs and different growth period at different levels of potassium treatments of flue-cured tobaccoThe potassium content in different organs increased with the amount of potassium increased.In early days after transplantation,the potassium content in phloem was the middle > the upper> the lower of different levels of potassium and in the 60 days after transplanting gradually changed into the lower > the middle > the upper.The potassium content in the middle phloem is far higher than the upper phloem at harvest time(90 days after transplanting).It proved that the potassium could from the upper,middle phloem to the lower phloem.The potassium content increased with the site height in the xylem,was the upper>the middle>the lower.But the potassium content in the phloem was higher than in the xylem.The potassium content in roots decreased gradually after transplanting.But the potassium content was increased,and then decreased gradually in 60 days after transplanting (topping).This is probably the growth center transfer from the point of the stem to the root due to the topping,induce the potassium flow to the root.We can saw that the potassium content of the high potassium level was higher than the low potassium level in tobacco leaves.The potassium content increased in tobacco leaves of the low potassium level treatment in early days after transplantation.The potassium content of the different site of leaves were the upper>the middle>the lower before the 60 days after transplanting.The potassium content of tobacco leaves gradually decreased with the growth and it obviously decreased after topping.The potassium content of the different site of leaves were the middle>the upper>the lower at harvest time(90 days after transplantation).But at the middle and the high potassium levels,the potassium content distribution different from the low potassium level.The potassium content performance the lower>the middle>the upper in whole growth period.It indicted that the potassium content of the lower leaves was higher than the upper leaves in the high potassium level.,but the upper leaves was higher than the lower leaves in the low potassium level.The results showed that the potassium content of leaves was higher in the early growth of flue-cured tobacco and it fall rapidly after the topping.It was probably due to the potassium transfer after topping.The total potassium accumulation in phloem and xylem increased with the growth period.The results were the lower phloem > the middle phloem > the upper phloem,the lower xylem > the middle xylem > the upper xylem.The potassium accumulation in the high, middle potassium level higher than the low potassium level,and showed that the potassium accumulation increased with the potassium fertilizer,but more potassium fertilizer useless. The potassium accumulation in leaves were the high level > the middle level > the low level. It showed that the potassium accumulation in leaves increased with the potassium fertilizer. The potassium accumulation in different organs was the leaves>the stem>the roots.The potassium accumulation of whole tobacco plant was the high level > the middle level > the low level when harvest.3 The effects of the chemical composition and physical characteristics of potassium treatments of flue-cured tobacco The nicotine content gradually increased with the growth period of leaves and rapidly increased,it performance the upper leaves > the middle leaves > the lower leaves and the middle level > the high level > the low level.The total sugar and reducing sugar content increased the growth period of leaves and rapidly increased,it performance the middle leaves > the upper leaves > the lower leaves.With the potassium increase,total sugar and reducing sugar content increases.Different levels of potassium in leaves and roots NR activity has been gradually declining With the extended period of growth,it performance the higher level > the middle level > the lower level.The invertase activity was highest in 45d after transplanting in different levels of potassium.With the leaves mature,the activity has been gradually declining and rapid decline in 60 days after transplanting,and higher potassium level than low potassium levels in the tobacco invertase activity.It shows that the fertilizer can promote the increase of carbon metabolism.The invertase activity overall downward trend in root and the activity is very low in the end.Different levels of potassium in leaf and root have effect on the MDA content.With the extension of the growth period,the MDA radiate upward trend and increased potassium levels the MDA accumulation inhibition.4 The Way of potassium loss of TobaccoThe tobacco root have potassium efflux in a few hours before treated in different levels of potassium.It indicted that the phenomenon of potassium efflux existed whether potassium more or less.17-leaf stage compared to 7-leaf stage and 12-leaf stage,the ability of tobacco absorption potassium significantly weakened,the potassium efflux became more, which may be due to the tobacco plants mature gradually moving aging,root absorption capacity declined.The effects of different potassium forms of tobacco root absorption potassium capacity at different growth stages.The results showed that potassium nitrate and potassium citrate were conducive to the potassium absorption of tobacco roots.But with one potassium form,no topping also prompted tobacco plant absorption of potassium,after topping tobacco plants efflux of potassium increases.This may be topping playing as a mechanical injury,induced a signal made the potassium go back tobacco roots,and transmitted to root very quickly.This may be the topping caused the potassium content declined.But daub IAA at the top of the tobacco plant or put the ferricyanide in liquid can enhance the potassium absorption But the root uptake the potassium by inhibiting when topping and having TEA.This paper also use artificial rainfall methods to study the effect of eluviate to tobacco leaves.The results found eluviate can make the potassium efflux in leaves,with the time extension the potassium decreased gradually in unit leaf area,eluviate to 5-6 h,no tobacco potassium efflux.It indicated that the rains.declined the potassium content of flue-cured tobacco is a way of potassium loss channels.