Stem Girdling Treatment Effects On The Transport And Distribution In Flue Cured Tobacco Growth And Nicotine And Potassium

By adopting physical and chemical girdling methods to treat stem phloem parts of potted plants and field-grown flue-cured tobacco, this article analyses different influences on both growing development of flue-cured tobacco and related output and quality. Meanwhile, it also focuses on how different modes impact transportation, distribution and generation of nicotine and potassium compositions of the said tobacco. And the research conclusions are as followed.1.When stem base parts of typical flue-cured tobacco are treated with physical girdling method or chemical one, dry matter contents, nicotine compositions and total potassium accumulations covering roots, leaves and its whole plants all reduce in different degrees. Among them, the tobacco treated with chemical girdling method greatly affects along with the given higher concentration of girdling agent. On the other, the test also finds that, through girdling treatments, nicotine, water and mineral elements will well climb upward along the targeted xylem, and root supply function will weaken, which causes to decrease nicotine synthetic amount in total. Although, the nicotine’s distribution pattern in the whole leaf remains unchanged.2.After girdling treatments of base parts, it approves that upper leaf segments have the most significant effect by measuring dry matter weights and nicotine compositions of leaves in different places, and have relatively less influence on those middle-low mature leaves. And by offering higher concentration of girdling agent, the potassium contents of tobacco leaves in different locations will increase by corresponding larger margins.3.After applying girdling methods towards different plant places, it is proven to much greatly affect to decrease dry matter weights and nicotine compositions along with girdling lower stem parts, and corresponding potassium contents of leaf segments show on-the-increase. Meanwhile, compared with other leaves, the upper ones have much more apparent influences on dry matter weights and nicotine compositions, and along with girdling treatments of lower plant parts, the trend becomes more apparent, and have less effect on bottom mature leaves. As for potassium contents of leaves in different places, the leaf segments beneath girdled point have higher potassium compositions but the ones under girdled point show slowly decrease. With the combination of Chapter Two and Chapter Three, it concludes that although potassium elements transport downward via phloem parts, spilled potassium materials can be blocked due to girdling treatments, the overall root supply function can weaken as well. And the total potassium absorbed dose can reduce, resulting in forming a large potassium accumulation gap between the upper leaves and the lower ones. Meanwhile, it well renders that potassium contents of flue-cured tobacco leaves can obtain accurate adjustments through correct girdling treatments.4. As the field experiment indicated, girdling treatments can obviously help the mature of flue-cured tobacco. And along with ahead-of-time girdling treatments, the leaves will be ripe earlier, well rendering that girdling method can adjust period of duration of this kind of tobacco. Despite synchronous girdling treatments to different place parts, the different degrees of ripeness of these leaves are not significant. But along with girdling treatments of upper parts, the influences on growth of tobacco leaves will become less and less effective for forming significantly differences. If topping process is implemented altogether with girdling one, nicotine, starch and total nitrogen contents of tobacco leaves in different places can all reduce obviously. But related reducing sugar, total sugar and potassium contents can have obviously increases. Please note that the above-mentioned effects can die away with girdling time retardation. And by girdling different plant parts, the represented pattern did not show any difference, except for the leaf segments beneath girdled point that have comparatively greater effects.5. After completion of topping process, girdling treatments of the phloem parts of flue-cured tobacco can interrupt the downward transportation of related assimilation substances and potassium but have no effect on transportations of water, mineral salts and nicotine in the interior of xylem, leading to decrease dry matter weights around the roots, slow synthesis pace of root secondary metabolites, and hamper nutrient absorption of tobacco for further affecting the growth of aerial growth parts. On the other hand, the evidence that both the distributed amounts and accumulated ones of both assimilation products and nicotine all decline in young parts, as well as potassium contents and related accumulated amounts of leaf segments have a markedly increase after girdling treatments of phloem parts, better rendering that girdling method can urge plant nutrients to have effective redistributions in the whole plant body.The study found:take topping the day lower leaves at 15% smear ring cutting agent, can shorten the flue-cured tobacco growing period in the field, improve tobacco mature period agronomic traits, to harvest the physicochemical index of tobacco tends to be reasonable, also can to achieve the purpose of extracting potassium alkalinity.