Studies On The Development And Maturity Of Cigar Wrapper Tobacco Leaves

Experiments in field were carried out in Shifang city of Sichuan Province from 2003 to 2004 , through the anatomic structure observation on the histology and cytology changes of Cuba cigar wrapper tobacco leaves in the course of growth and development, studied the change law of chemical and physical characteristics ,the aromatic substance of cured cigar tobacco leaves with different varieties and maturities, the results showed as follows:1 The histology and cytology changes in the course of growth and development with Cuba cigar wrapper tobacco leavesUnder the condition of shading, mesophyll tissue differentiated into palisade tissue and spongy tissue when the leaves were 10cm in length, the intercellular space of spongy tissue began to run through when the leaves were 20cm in length, the cells of spongy tissue appeared to shrinking phenomenon when the leaves were 30cm in length, it took place relatively early especially in the lower leaves. The thickness of leaf blade, palisade tissue and spongy tissue and the area of intercellular spaces increased with the increasing of the leaf length, and decreased with the rising of the stalk position. The variation tendency of the thickness of leaf blade at fixed length is: lower leaf > upper leaf > middle leaf, this may be because that the middle leaves expanded fully and the area of leaf was maximal under the condition of shading culture manners. With the growth of leaves, palisade tissue thickness/spongy tissue thickness and palisade tissue thickness/leaf thickness increased, and reached the top at 40cm length, and then dropped gradually. The cell density in palisade tissue increased before 5cm length, and then began to decline constantly, until to fixed leaf length, and it also increased with the rising of stalk position.With the growth of leaves, the amount and area of vessel in the first class lateral vein of leaves increased, at different stalk position they were shown as: Upper leaf >lower leaf> middle leaf, this may be because that the growth environment of the upper leaves was relatively better than other position leaves, such as the light, temperature and air flowing, etc., so the transpiration amount of the blade was bigger and promoted the development of the vessel.2 The anatomic structural observation of fresh middle leaves during the maturing processThrough the anatomic structural observation of fresh leaves during the maturing process with different varieties (Cuba cigar wrapper tobacco, Shifang sun-cured yellow tobacco, Shifang sun-cured red tobacco), it showed that there was close relationship between the maturity and the leaf structure. With the rising of leaf maturity, the thickness of leaf, palisade tissue and spongy tissue presented increasing tendency, but the cell density of palisade tissue presented decreasing tendency in Cuba cigar wrapper tobacco and Shifang sun-cured yellow tobacco, the leaf structure finally became looser. The thickness of leaf, palisade tissue and spongy tissue firstly increased, and then decreased slowly; the cell density of palisade tissue decreased all along during the maturing process in Shifang sun-cured red tobacco.3 The ultra structure observation of Cuba cigar wrapper tobacco leaves during the maturing processWith the rising of maturity, the cell inclusion reduced, and some appeared disorganization phenomenon; the nucleus was intact at first, then appeared hollow nuclear membrane, the shape became abnormal, and finally disappeared. The starch grains in the chloroplast gradually became smaller, the number of black plastoglobuli increased from Ml to M2, then decreased from M2 to M3.4 Appraisal and analysis on the apparent quality of cured leaves for different varieties and maturitiesThe results of the appraisal and analysis on the apparent quality of the three varieties with different maturity showed that M3 was the best in the color, shine, oil, tenacity and body. Cuba cigar tobacco leaves were better than Shifang sun-cured tobacco in color and shine.5 The relationship between maturity of cigar wrapper tobacco leaf and its aromatic component for different varietiesThe neutral aromatic components in the three cigar wrapper tobacco varieties were extracted by using simultaneous distillation-extracted equipments, 32 important aromatic components which contributed to the tobacco flavor characteristics were identified and quantitatively analyzed by GC/MS. The results showed that the aromatic content was obviously different in different maturities and varieties. The total amount of aromatic components in Shifang sun-cured red tobacco was the highest, Shifang sun-cured yellow tobacco took the second place, Cuba cigar wrappertobacco was the lowest. Aromatic components changed dynamically in line with certain rules during the maturing stage, most main aromatic components increased with the rising of maturity in Cuba cigar wrapper tobacco, but the total amount decreased, this because that some matter decreased which was great such as neophytadiene, phytol, bisbutyl phthalate, etc. The total amount of aromatic components reached maximum at M2 in Shifang sun-cured yellow tobacco. Most main aromatic components increased with the rising of maturity in Shifang sun-cured yellow tobacco, but the total amount changed not evidently.6 The relationship between maturity of cigar wrapper tobacco leaf and its chemical composition for different varietiesThe reducing sugar content and the reducing sugar/total sugar in the leaves increased significantly with the rising of maturity, whereas total nitrogen, K+, starch, nicotine content and total sugar/nicotine, K7C1 presented decreasing tendency. During the maturing stage, the total sugar content firstly increased, then decreased in the leaves of Cuba cigar wrapper tobacco and Shifang sun-cured yellow tobacco, opposite to the Shifang sun-cured red tobacco. It can be included that the chemical composition and its ratio was more harmonious at M3, the inherent quality was better as compared with Ml andM2.7 The relationship between maturity of cigar wrapper tobacco leaf and its physical characteristics for different varietiesThe physical characteristics of tobacco leaf have discrepancy among the different maturities and varieties. In Cuba cigar wrapper tobacco leaves the thickness of leaf blade reached maximum at M2, the weight of per leaf, the weight unit area and the stem rate in leaf increased along with the maturity improved, however the equilibrium moisture decreased along with the maturity improved. In Shifang sun-cured yellow tobacco leaves and Shifang sun-cured red tobacco leaves the thickness of leaf blade, the weight of per leaf and the weight unit area was maximal at M2 and was minimal at Ml, the stem rate in leaf reached maximum at M3, whereas the equilibrium moisture reached minimum at M3.From the relationship of maturity with the anatomical structure, apparent quality, aromatic component and physical characteristics, it can be concluded that the optimum harvesting time was 80 days after transplanting for the middle leaves of Cuba cigar wrapper tobacco when the leaf green color faded and turned yellow, the midrib fully turned white and the lateral vein whitened 1/3, the leaf tip drooped, the...