Study On The Correlation Between Rhizome Expansion And Carbon And Nitrogen Metabobolism Of Wild Poa.L

As a kind of cold-season turfgrass which is mainly and widely used in the cold and dryland lawn,Kentucky bluegrass is distributed in most of the China.The rhizome expansion of Kentucky bluegrass means the underground rhizome it posses which produces tiller and has regeneration,which is the one of main characteristic that differs from other non-rhizome lawn plants.It is also the comprehensive performance which has drought resistance,cold resistance,trampling resistance,cutting resistance and other turf characteristics.Carbohydrates are essential energy sources for plant life activities,and nitrogen compounds such as amino acids are the basic constituent units of protein,which is essential for the growth of plants.The study comprehensively evaluate the rhizome expansion of 12 Kentucky bluegrass by using pot method and determine the contents of carbohydrate and nitrogen compounds and their related enzymes activities in the leaf,crown and rhizome.The main carbohydrate and nitrogenous compounds and their synergistic relationships among with the rhizome expansion were studied in order to provide the theoretical basis for the regulation of rhizome of Kentucky bluegrass.The main results were as follows:1.Poa pratensis?Sunan?had the highest number of tillers in Kentucky bluegrass,and Poa pratensis?Yuzhong?had the largest rhizome extension distance,aboveground plant volume,rhizome plant number,rhizome volume and rhizome surface area,the longest rhizome diameter and stem length,and Midnight Poa pratensis had the largest coverage area per plant and number of rhizomes.The order of the rhizome extensibility of the experimental wild grasses was: Poa pratensis?Yuzhong?> Midnight Poa pratensis > Poa pratensis?Qinzhou?> Poa pratensis?Sunan?> Poa pratensis?Qingshui?> Poa pratensis?Lingtai?> Poa pratensis?Weiyuan?> Poa pratensis?Kangle?> Poa pratensis?Xihe?>Poa pratensis?Tianzhu?> Poa pratensis?Xiahe?> Poa pratensis?Anding?.2.The order of the stored carbohydrate components in different organs of Kentucky bluegrass were: fructan> mannitol> fructose> sucrose> glucose.The order of the stored carbohydrate components in different organs of Kentucky bluegrass were: rhizome >crown > leaf and the rhizome is the main place which stored carbohydrate components.3.The activities of SuSy,AI and NI in carbohydrate and related enzymes were negatively correlated with the indexes of extension?except stem length?,and the other carbohydrate and related enzymes were positively correlated with the indexes of extensibility of test materials.4.In the leaves,there were very significant positive correlations between the activity of SPS and the content of fructose and the expandability.There was a significant positive correlation between the content of mannitol and the expandability.There was a significant negative correlation between the activity of NI and expandability.The correlation size was as follows: SPS> fructose> mannitol> NI> SuSy> AI.In the crowns,there were very significant positive correlations between the activity of SPS,the content of fructose,sucrose,glucose and mannitol and the expandability.There were significant positive correlations between the content of fructans and the expandability.There was a significant negative correlation between the activity of NI and expandability.The correlation size was as follows: SPS= fructose> sucrose> glucose> mannitol> NI> fructans.In the rhizomes,there were very significant positive correlation between the content of glucose,fructans,mannitol and sucrose and the expandability.There were significant positive correlations between the content of starch and fructose and the expandability.The correlation size was as follows: glucose> fructans> mannitol> sucrose> starch> fructose.In the whole plant,there were very significant positive correlations between the content of mannitol,fructose,sucrose and glucose,the activity of SPS and the expandability.There were significant positive correlations between the content of fructans and starches and the expandability.There was a significant negative correlation between the activity of NI and expandability.The correlation size was as follows: mannitol> fructose> sucrose> glucose> SPS> NI> fructan> starch.5.The contents of NH₄⁺-N and Pro were the highest in the leaves,and the content of NO₃^-N was the highest in the crown and the free amino acid content was the highest in the rhizomes.NR and GS activities were the highest in the leaves,and the activities of GOGAT and GDH were the highest in the crown.6.The content of NH₄⁺-N and the activity of GDH were negatively correlated with the indexes of extension?except stem length?,and the other nitrogen compounds and related enzyme activities were positively correlated with the indexes of extension of test materials7.In the leaves,there were very significant positive correlations between the content of Pro and free amino acids and the expandability.There were significant positive correlations between the content of nitrate,the activity of GOGAT,GS,NR and the expandability.There was a significant negative correlation between the content of ammonium nitrogen and expandability.The correlation size was as follows: Pro> Free amino acids > GOGAT > NO₃^-N> GS> NH₄⁺-N> NR.In the crowns,there were very significant positive correlations between the activity of NR,GOGAT,the content of Pro and the expandability.There was a significant negative correlation between the content of ammonium nitrogen and expandability.The correlation size was as follows: NR>Pro>GOGAT> ammonium nitrogen.In the rhizomes,there were very significant positive correlation between the content of nitrate nitrogen,the activity of GOGAT and the expandability.There were significant positive correlations between the content of Pro,the activity of NR and the expandability.The correlation size was as follows: nitrate nitrogen >GOGAT>NR> Pro?In the whole plant,there were very significant positive correlations between the content of nitrate nitrogen,Pro and free amino acids,the activity of GOGAT,NR and the expandability.There was a significant negative correlation between the activity of GS and expandability.There was a significant positive correlation between the content of ammonium nitrogen and expandability.The correlation size was as follows: GOGAT > NR> Pro> nitrate nitrogen > free amino acids > ammonium nitrogen > GS.