Study On Regulation Of Tillering Occuring With Endogenous Hormone In Kentucky Bluegrass

Kentucky Bluegrass (Poa pratensis L.) is one of the genus lolium germplasmresources and an important part of grassland and meadow vegetation in China. It wasnot only as a fine livestock forage resources, but also delicate texture, strong regener-ation capacity and cut resistant, long green period, graceful quality and strong, so itwas widely applied to garden and ecological greening. Tillering was an importantbiological characteristics of Gramineae turfgrass, which was the phenomenon thatnew aboveground shoots grow from axillary sheath and was one of asexual reprodu-ction. The plant can form much nutritive material to promote the development of indi-vidual plant by tillering. Tillering was also conducive to expand the plant nutrient areaand covers area, and effectively keep down the weeds and enhanced turfgrass resist-ance and adaptability. Therefore, increasing tiller number can improve the grass quail-ty and resistance. Kentucky tillering was the joint action by gene, water, fertilizer, gas,heat and endogenous endogenous hormone.There was a far-reaching significance toresearch the endogenous hormones change and differences of physiological indexes ofKentucky bluegrass. So this study used the commercial kentucky bluegrass(MidnightⅡ,Baron, Kentucky) as material to determine three endogenous hormone (IAA、ZR、ZT)and the content of the chlorophyⅡ, soluble sugar,soluble of protein,catalase, and inorder to further explain the tillering ability, the last time of tillering peak time, changeof endogenous hormones and the difference of physiological indices between differentvarieties.1.In the process of kentucky bluegrass tillering, the variation of IAA and ZR＋Zin three varieties was similar, which were a single-peak curve. A week after seedsgermination, the content of IAA reached the maximum(120ng/g) and then decreased;ZR＋Z content increased firstly as the growth of bluegrass and decreased in35d aftergermination when it reached the maximum (MidnightⅡ205.82ng/g, Baron146.67ng/g, Kentucky172.16ng/g) in room conditions, ZR＋Z content increaseed firstly asthe growth of bluegrass and decreased in42d after germination when it reached themaximum (MidnightⅡ232.12ng/g, Baron116.97ng/g, Kentucky164.38ng/g) in field conditions. In the process of Kentucky bluegrasstillering, on one hand the IAAcontent decreased rapidly after germination,which promoted thetillering, on theother hand, the content of Z+ZR increased with the increasing of Kentucky bluegrasstillering, and decreased with the tillering capacity.2. The IAA/(ZR+Z) ratio of MidnightⅡ, Baron and Kentucky decreased firstly andthen increased in different growing conditions. During tiller of bluegrass, the averageof Kentucky bluegrass tiller number increase at begin, and decrease at last, and it wascontrast with IAA content. However, it was positively correlated with ZR＋Z content.3.In terms of different varieties of tillering ability, average tiller number of Mid-nightⅡwas higher than Baron and Kentucky. The tillering ability of those Kentuckybluegrass varieties increased firstly as the grow stage and decreased in35d aftergermination when it reached the maximum (MidnightⅡ:2.45tillers/strain, Baron:2.15tillers/strain, Kentucky:1.98tillers/strain) in room conditions, the tillering ability ofthose Kentucky bluegrass varieties also increased firstly as the grow stage and decrea-sed in42d after germination when it reached the maximum (MidnightⅡ:3.67tillers/strain, Baron:1.99tillers/strain, Kentucky:2.98tillers/strain) in field conditions.4.The variation trends of chlorophyll and soluble of protein Midnight Ⅱ, Baron,Kentucky bluegrass were similar, all presented a single peak curve, the contents werehold on at Peak value(the chlorophyll:2.2145mg/g,2.0000mg/g,2.0134mg/g; thesoluble of protein:0.85mg/g,0.64mg/g,0.77mg/g) for a long time and then dropped,this variation trends was similar to the average number of Kentucky bluegrass, whilethe contents of soluble sugar and the activity of catalase were increased with the gro-wth stage.5.The content of IAA and Z+ZR of different varieties were similar: the MmidnightⅡ> Baron>Kentucky; the content of chlorophyll and soluble protein: MidnightⅡ>Baron>Kentucky; the content of soluble sugar and catalase activity: theMidnight Ⅱ>Kentucky> baron.6. The tillering ability were: Midnight Ⅱ> Baron>Kentucky.7. The peak of tillering is35d (under culture room conditions) and42d (underfield conditions) after germination of Kentucky bluegrass.