Study In Effect Of Delay Harvest In Microscopic And Submicroscopic Structure Of Tobacco Leaf

Tobaccoleaf fully maturity is the most essential quality requirements of gainexcellent flavor and aroma,grasp the maturity of tobacco leaf is the key factor toimprove the quality of tobacco leaf. This study use the four species that mainly growin Yunnan:‘K326’、’Yunyan87’、’Yunyan97’、’Honghuadajinyuan’, the upper lobeand middle lobe,normal harvest0d、delay7d harvest、delay14d harvest、delay21d harvest as the research material, using paraffin section method, temporary slicemethod, scanning electron microscopy and Transmission electron microscopy methodto observe the change of organization structure、glandular hairs、chloroplast in thetobacco leaf in the process of delay harvest, from the aspects of anatomy toresearchthe optimum harvest period and the effect ofdelay harvest in tobacco leafstructure. The results of the study are as follows:1、 In the process of delay harvest, the changes in organization structure oftobacco leaf were: in the early harvest period, palisade tissue cells in shape of longcolumnar in order lined up, the outline of palisade tissue and spongy tissue is clear,the boundary is obvious, the gap of cell is moderate. As the harvest delay, palisadetissue cells gradually shorten, organization cell structure gradually disorder, theoutline of tissue gradually fuzzy, the gap of cell gradually increase, organization cellcells gradually disintegration,and the degree gradually serious. Different maturityperiod, leaf thickness、 the thickness of palisade tissue and other anatomicalparameters show significant differences among species and lobe.in the same period, most species, with the rising of the stalk positions, the leaf thickness, the palisadetissue thickness were decreased.2、In the process of delay harvest, the changes in glandular hairs of tobacco leafwere: All kinds of glandular hairs include base、handle and head. the kind of glandularhairs that observed in this study include long glandular hairs (included single cell andmulticellular gland head)、short glandular hairs and epidermal hair, not observed thelong branch glandular hairs. long and short glandular hairs were originated fromprotoderm cell on the leaf primordium, there was no differentiated difference betweenthe long glandular hairs and short one at the initial glandular cells, two types ofglandular differentiation in the initial stages of the formation of glandular head.longones was dominate hairs on the surface of leaf, In the early and mid harvest period,the quality of Tobacco mainly rely on the long glandular hairs, short glandular hairsdeveloped late with steady quantity, while in the late harvest period, mainly rely onthe short ones. In the early harvest period, most of the glandular hairs are in the shapeof upright, into the mature period, gland secretions spillover in great quantities, thehead of long and short glandular hairs as the delay show different degree of atrophydue to the secretions spillover, handle and head show flat due to shrinkage, with thedelay of the harvest, part of the long ones, head falls off and become Non-head, as aresult, the number of Non-head glandular hairs increase, and the shape of glandularhairs are lodging. the development of glandular hairs in the lower epidermis are betterthan upper, the number of Non-head in the upper are more than lower. There are existsignificant differences in glandular hairs density in different species、four period ofsame species and upper、 lower epidermis. Most period, the density of longglandularharis are more than short ones, with the harvest delay, the density of theNon-head glandular hairs gradually increases, the density of the have-head glandularhairs gradually decreases.3、In the process of delay harvest, the changes in chloroplast of tobacco leaf were:Most species, the chloroplast membrane has disintegration in normal harvest0d, butcan observed some granal lamella, upper lobe,‘Yunyan87’ and ‘Yunyan97’, middlelobe,‘Yunyan97’, part of the chloroplastmembranewas complete, then disintegrated, also can observed some granal lamella. In the early harvest period, the cell wallstructure was complete, most starch grain in the shape of oval, in order along the wallline up, small size, less. with the harvest delay, the cell wall gradually disintergrated,the change of the shape of starch grain: oval→irregular→round→spherical, graduallynot along the wall line up, in chaos distribute in the cell, big size, more. osmiophilicparticles always apper in the process of delay harvest, the amount with the harvestdelay gradually increase. The process of senility of tobacco leaf was the chloroplastgradually disintegrate and starch grian gradually increase, the chloroplast disintegratewas not synchronize and slow.4、Comprehensive the change of microscopic structure and submicroscopicstructure during delay harvest, it is concluded that the optimum harvest period of theupper lobe and middle lobe of four species in the four periods were: in the upper,‘K326’ should not be more than14d,‘Yunyan87’ should not be more than7d,‘Yunyan97’ should not be more than14d,‘Honghuadajinyuan’ should early harvest;in the middle,‘K326’ should not be more than21d,‘Yunyan87’ should not be morethan14d,‘Yunyan97’ should not be more than7d,‘Honghuadajinyuan’ should earlyharvest.