| Tobacco is a crop which has relatively high economic value. There are 17species of elements are known requisite to tobacco growth at present. Thereinto K, Ca,Mg and other 6 species are macro elements, Fe,B,Cu,Mn,Mo and other 4 speciesare microelements. Nutrient elements plays a very important role in the growth anddevelopment of tobacco plant, it not only affects the production of tobacco, but alsochange the combustive ability, colour and lustre, flexibility, smell and filling power oftobacco leaves. Mg is a component element of chlorophyll and some synthetase, andcould participate signal transduction in Adversity intimidate. Due to the increase ofconsumption of Mg which is in the soil, and neglected elements of magnesiumsupplement of the Fertilizer prescription, result in Mg shortage phenomenon comeinto birth in many tobacco production areas, and become an important factor toaffect yield and quality improvement of tobacco leaves. This article researchesflue-cured tobacco variety K326 seedling as the material by hydroponic planting, usedatomic absorption spectrometer, ion chromatogram, and other modern analysistechniques in study changes of nutrient absorption, investigated systemically ondistribution and absorption of major nutrients such as Fe,B,Cu,Mn,Mo in differentMg strength levels, and it effect on trichome density of lack for different nutrients influe-cured tobacco, as well as investigates changes of chlorophyll concentration,activity changes of superoxide dimutase (SOD), peroxidase (POD). The results are asfollows:1. Mg is closely related to growth of tobacco and dry matter accumulation intobacco plants, the growth of tobacco leaves is affected most obviously. The growthof tobacco was inhibited without environmental Mg supplication, Mg element wasredistribution in tobacco plant, it was lose from old leaves, a part of which wasfocused on the bottom leaves, another part was transported to the new leaves. Incertain supplication of Mg conditions, the highest Mg concentration is exist in bottomleaves, central leaves have high Mg concentration too. 2. With the increase of environmental Mg nutrition, absorption ability of Ca, K,Mn is enhanced in flue-cured tobacco, absorption of Cu is reduced. The accumulationquantity of the elements in leaves are accounted of absolutely superiority at full Mgstrength level. The distribution of Ca, K, Mn in the spaces between leaves arerelatively uniform, and the distribution of Cu is very uneven in insufficient for Mgcondition, Cu content in some upper and central leaves was significantly higher thanother leaves, absorption and distribution of Mn could be adjusted in tobacco which inlack of Mg environment, but with the growth of tobacco plant, the disorder ofabsorption which exist in prophase is gradually disappear and then become normally.3. The chlorophyll concentration levels in leaf is increased with the Mgconcentrations rise. Activities of POD and SOD in adversity are increasing rapidly influe-cured tobacco. When ameliorated the Mg concentrations and ventilationconditions, the activities of POD and SOD are slower increases.4. When the Mg concentration greater than160μg/mL, the glandular trichomedensity increases. When the Mg concentration less than 80μg/mL, the glandulartrichome density decreases. This change is more obviously in the upper epidermis.lack for B, Fe, Ca cultivate could produce notably changes of tentacle density. Whenglandular trichome in lacked element condition, the rate of shrinking, apoptosis anddesquamate was accelerated. The desquamate rate of all kinds of glandular trichomein upper epidermis is obviously higher than that in nether epidermis, lack of Fe,Bhave great effect on glandular trichome density in prophase, lack of Ca,Fe have greateffect on glandular trichome density in anaphase, lack of Mo has little impact onglandular trichome density.
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