Research On Leaf Structure And Chemical Component During Reproductive Period Of Different Flue-cured Tobacco Varieties In Yanbian

Abstract:With three main varieties: Jiyan9, Jiyan10and9407as test materials in Yanbian area,the test launched in Jilin yanbian agricultural science research institute test site at2012-2013.Using a paraffin, TEM slices, chemical analysis techniques，which analyzed change of the leaftissue structure, ultrastructural features and main chemical components during the development ofvarious periods of leaf, and find the relationship between leaf structure and chemical compositionof Yanbian flue-cured tobacco, which provided the basis for breeding new varieties and cultivationtechniques upgrading. The main results of the test were as follows:1. Through the observation and study on leaf tissue structure during the process of growthand development of flue-cured tobacco, the result showed that with the increase of the length ofthe blade, the cells no significant changes in the upper and lower epidermis, leaves graduallythickened, palisade tissue longitudinal growth faster which arrangement tends to disorder, lateralgrowth of spongy tissue was rapid, cell gap from less to more, mesophyll cell structure graduallyloose, when leaves gradually mature, upper and lower epidermis became incomplete, palisade andspongy tissue accumulated large amounts of starch granules,mesophyll tissue began to collapse,the cells gradually shrinkage cracking. Comprehensive comparison, the upper leaf tissue structuremore closely, middle leaves structure were moderate, the lower leaves very loose. Comparedwith9407and Jiyan9, middle and upper leaves thickness,palisade tissue thickness,the organizationratio and the ratio between palisade tissue and leaf thickness of Jiyan10is higher,and mesophylldisintegrated slowly in the late growth.Overall,new varieties Jiyan10tissue structure wasmoderate,the organization ratio was coordinating, photosynthetic productivity was higher, and hada strong yield performance.2.By studied on ultrastructural changes of flue-cured tobacco leaf cells during growth anddevelopment,which showed that during leaf development,ultrastructural changes of three varietiesof flue-cured tobacco leaf cells was basically the same,cell vacuole was smaller at early period,osmiophilic particles were mainly distributed in the cytoplasm, mitochondria was mainlydistributed around the nucleus, chloroplast structure was intact,grana sheet was clearly visible,cellnucleus was larger with regular shape,less starch granules accumulated in leaves.With leaf ageincreased,the chloroplast grana lamellae increased,the number of osmiophilic particlesincreased,blade synthesis capabilities is strong,the starch granules increased,mitochondrial inner ridge structure also increased,when the leaves maturity,the outer membrane of chloroplastsgradually disintegrated, grana layer structure gradually disappear, the starch granules significantlyincreased, mitochondrial structure gradually incomplete, nucleus atrophy. The main differencebetween of different varieties was chloroplasts, starch grains and osmiophilic particles.In the earlyleaf development,Jiyan10palisade cell chloroplasts and starch grains were more than Jiyan9and9407;In the middle of leaf development, starch particle volume increased rapidly of9407andJiyan9,but osmiophilic particles were less,osmiophilic particles of Jiyan10was larger;In the lateof leaf development, Jiyan10chloroplast structure was still relatively intact,9407and Jiyan9chloroplast envelope degraded rapidly. The main difference between the leaves on different partsof the ultrastructure was starch granules and osmiophilic particles, lower leaves with less starchsynthesis, the contents are not full, followed by the middle leaves, the upper leaves was more;osmiophilic particles of middle leaves were more than upper leaves, followed by a minimum oflower leaves.3.Through studied on main chemical ingredient content variation during the process ofgrowth and development of flue-cured tobacco in Yanbian, which results showed that:with theextension of leaf development process, starch content increased of middle and upper,total sugarcontent increased firstly then declined of three parts leaves,total nitrogen content had beendeclining, tobacco nicotine content had been rising.Flue-cured tobacco after the roast containedhigh starch content of three varieties, total sugar content was high, nicotine content was low,sugar nicotine ratio greater than10of different varieties, Jiyan10had highest total amount ofaroma constituents of flue-cured tobacco,mainly neophytadiene content was significantly higherthan that of other two varieties.there was a certain relationship between the chemical compositionand structure of tobacco leaf,palisade tissue of Jiyan10was relatively more developed,leafthickness was moderate, leaves structure was more loose, overall,chemical composition ratio ofthe Jiyan10was more coordinated, aroma of flue-cured tobacco was better,yield optimalperformance.