Study On Leaf Histological And Cytology Changes In Flue-cured Tobacco Planted In Two Soil Textures In South Anhui During Growth And Development

The leaves of flue-cured tobacco cultivated in alluvial sandy soil in south Anhui have obvious sensory evaluation of sweet aroma, which cultivated in rice clay soil having not or little. Therefore, 2 typical tobacco soils in south Anhui were selected to investigate the leaf tissue structure and cell structure changes of flue-cured tobacco cultivated in alluvial sandy soil and rice clay during growth and development through field production in 2008-2009, and the results showed that:1. Changes of leaf histological characteristics of flue-cured tobacco planted in alluvial sandy soil during growth and developmentThe leaf palisade cell density of flue-cured tobacco planted in alluvial sandy soil changed like"∧"shape during grow and development. Time for palisade cells rapidly division was in the order of bottom leaf>top leaf>middle leaf,but the enlargement rate of intercellular space in the reverse order, and the total number of palisade cells had no relation with stalk position. In palisade cells elongation stage, the palisade and the leaf thicknesses were both in the order of bottom leaf>top leaf>middle leaf, with well relatively developed palisade tissues in bottom leaf and top leaf. Sponge tissue of the bottom leaf had been being thicker after cells division, in which the difference between middle leaf and top leaf was not obvious. Mesophyll tissue of the bottom ripe leaf was thicker, that significantly different with top leaf and middle leaf, but the leaf structure was excessively loose.2. Ultramicro structure changes of flue-cured tobacco leaf planted in alluvial sandy soil during growth and developmentThe organelles in upper epidermis cell began to degradation after 5cm in leaf length, but the size of cell have been increased. The organelles degraded completely when the leaf was ripe,and just cell wall in the cell. It was palisade cells division stage before 20cm in leaf length, also being the stage of chloroplasts developing; and the chloroplasts began to play functions at 10cm in length. The small vacuoles have fused to be a single large central vacuole at 20cm in length. After 50cm in length, the structure of chloroplasts became perfect, so cells entered mainly synthesis function period. And then, with the starch granules enlargement and increasing, the chloroplasts began to degradation, so osmiophilic globule increased in the chloroplasts. In the ripe leaf, plentiful of starch granules and osmiophilic globules were accumulated in the chloroplast. It was concluded that fertilizer using should accelerate the chloroplasts development in the early stage of tobacco leaves grows, especially nitrogenous fertilizer.3. Changes of leaf histological characteristics of flue-cured tobacco planted in rice clay soil during growth and developmentThe palisade cell density of tobacco leaf planted in clay changed like"∧"shape during grow and development. Differences in palisade cell density among stalk position were discovered in the palisade cells elongation stage and the intercellular space enlargement stage, with cell density of bottom leaf less than of both middle leaf and top leaf, but the total number of the palisade cells was independent of stalk position. In cell elongation stage, palisade tissue, sponge tissue and the leaf all thickened following the rising of stalk position, and both bottom leaf and top leaf had the relatively well developed palisade tissues. The top ripe leaf structure was dense, of which the cell density significantly different with top leaf and middle leaf. Although the mesophyll tissue of bottom ripe leaf was thicker, the leaf structure was excessively loose.4. Ultramicro structure changes of tobacco leaf planted in rice clay soil during growth and developmentAt 5cm in leaf length,the top epidermal cell of tobacco leaf was mature, and enlarging until the leaf was ripe. It was palisade cell division stage before 20cm in leaf length, with the chloroplast developing. After 30cm to 40cm in length, the structure of chloroplasts became perfect, so the cells entered mainly synthesis exuberant function period and began to accumulate assimilation products from 60cm in length. The photosynthetic capacity reduced after the leaves length fixed, with the lamellae of thylakoid disappeared gradually. In leaf ripe stage, more starch granules and osmiophilic globules accumulated with the chloroplast in degradation.5. Comparison on leaf histological characteristics of flue-cured tobacco planted in alluvial sandy soil and rice clay soil during growth and developmentThe soil type could affect the rates of both cell division and intercellular space enlargement of the palisade tissue, but effect for the number of the palisade cells was not obvious. The difference in mesophyll tissue between the two soil types was obvious in palisade cells elongation stage. The leaf palisade cells of tobacco planted in alluvial sandy soil elongated early and developed well relatively in palisade cells elongation stage. The mesophyll cells of tobacco planted in rice clay soil developed later and mesophyll tissue was thicker in mature stage.6. Comparison on cell ultrastructure of flue-cured tobacco leaf planted in alluvial sandy soil and rice clay soil during growth and developmentThe differences of cell ultrastructure of tobacco leaf cultivated in between alluvial sandy soil and rice clay soil were not greatly, prior to 5cm in leaf length. Where after, the organelles in upper epidermis cell began to degradation, which planted in alluvial sandy soil degraded quicker. And the palisade cell of tobacco leaf cultivated in alluvial sandy soil developed relatively quickly manifested principally in which chloroplasts began to cling to the cell wall and play functions at 10cm to 15cm in leaf length, and play powerful functions at 30cm in leaf length, with the grana lamellae thickened obviously at 20cm in leaf length and the vacuole was maturity at 30cm in leaf length. On the contrary, the palisade cell of flue-cured tobacco planted in rice clay soil developed slowly in which chloroplasts began to play full functions at 20cm in leaf length and was in functional period of vigorous at 40cm to 50cm in leaf length. The starch granules and the osmiophilic globules accumulated in palisade cell of flue-cured tobacco cultivated in rice clay soil was not richer than that of cultivated in alluvial sandy soil at the fixed leaf length, and the cellular contents degraded insufficiently in ripe leaf planted in rice clay soil.The differences in leaf tissue structure and cell structure during growth and development could be one of reason for different aroma style formations of flue-cured tobacco leaf cultivated between the two soil textures.