Influences Of Density On Physio-ecological Indicators And Quality Of Flue-cured Tobacco In Guiyang

In2010,a field experiment was employed to study the changes of agronomiccharacteristics，oganizational characteristics andphotosynthetic characteristics andquality of flue—cured tobacco under planting density,K application and theirinteractions using the tobacco cultivar K326inKaiyangtown in Guiyang.The resultswas followed：1．The study of agronomic characteristicsWith the increase of planting density，leaf area and number per plant，length，width and area of different parts of tobacco plants showed the tendency of increasedand then decreased． Planting density certainly affected the leaf length，width andarea,thetreatment D2which was planting density18150trees／ha Was too higher．Itindicated that adding planting density could improve thetobacco agronomiccharacteristics and tobacco production in low planting density．2．The study of photosynthetic characteristics2.1．The study ofphotosynthetic characteristics on different growth periodThe study proved that applying pplanting density increased capture volumeandconversion efficiency of light， ultimately promoted Pn， was beneficial tosubstanceaccumulation of assimilation product．Allphotosynthetic indexs of treatmentD2(planting density181500trees／ha)among nine treatments were the biggest．2.2．Effects ofplanting density on diurnal changes of photosynthetic characteristicsinflue-cured tobaccoThe results showed that the net photosynthetic rates(Pn)，stomatalconductance(Gs)，intercellular CO2concentration(Ci),transpiration rates(Tr)，relative air humidity(RH),andleaf temperature(TL)diurnal changes of the fivedensities all appeared as single peak curves，the majority of peaks presented to11：00or13：00．and they all didn’t show middaydepression；Higher or lower rangeplanting density decreased photosynthesis，the structure of planting density18150trees／ha showed that Pn Was too higher and photosynthetic capacity Was toostronger was rational；It was Gs that affected thechanges of Pn among thephysiological factors，and PAR played very important rolesin the hanges of Pn amongthe ecological factors；Perhaps muchrainyof Guiyangprovided enough water for tobacco which was the main cause of no middaydepression phenomenon．3． Effects ofplanting density on oganizational characteristics.With the increase of planting density，Palisade tissue thickness, Spongy tissuethicknessshowed the tendency of increased and then decreased．thetreatment D2whichwas planting density18150trees／ha Was too higher．It indicated that addingplanting density could hadmore appropriate for the palisade and spongy tissue thickness4．The study ofchemical components in flue-cured tobaccoThe results showed that：In planting density D2(18150trees／ha)conditions，K+wasabsorbed better than other treatment，and the content of total sugar，reducingsugars in upper leaves，protein in upper and middleleaves were suitable；In plantingdensity D3(17385trees／ha) conditions，the content of total sugar and reducingsugars in lower and middle leaves, protein in lowerleaveswere suitable，All the results suggested that structureof treatment D2which were plantingdensity18150trees／ha on the quality offlue-cured tobacco leaf were reasonable，andthe tobacco quality was better．5．The study ofneutral aroma components contents in flue—cured tobaccoResults showed that： planting density extremely significantly affected, with theincrease of planting density,the contents of products egraded by carotene、productsofbrowing reaction、products degraded by cembranes、neophytadiene andneutralaroma components in postshowed the tendency of twin Peaks.All the results suggested that structure of treatment D2which wasplantingdensity18150trees／ha on the quality offlue-cured tobacco leaf was reasonable,andthe tobacco quality was better．...