Studies On Growth Characteristic Of Populus Deltoides ’Lux’×(P.Deltoides ’Shanhaiguan’×P. Simonii)’Zhaiguan Ⅰ’and P.Deltoides ’Lux’×(P. Deltodies ’Shanhaiguan’×P.Simonii)’Zhaiguan Ⅱ’and P. Deltoides ’Lux’×(P.deltoid’

P. x euramericana cv.’Neva’are used as the control of Populus deltoides’Lux’x(P. deltoides’Shanhaiguan’×P.simonii)’Zhaiguan I’and Pdeltoides’Lux’×(P.Deltoides’Shanhai guan’×P.simonii)’ZhaiguanⅡ’and Pdeltoides ’Lux’×(P.deltoid’Shanhaiguan’×p. simonii)’Zhaiguan XI’were studied in this papers so as to the growth law, growth model forecasting, biomass and photosynthetic characteristics, as the instruct intensive short-rotation poplar cultivation and provide a scientific basis for management decisions. The experimental results showed that:(1)The growth law of4black poplar clones seedlings was that:from May to August was a fast growing period,and they entered the late growth stage in August-mid late, high growth and diameter growth pattern were similar,the growth appeared to be’fast-slow-fast’growth rhythm.May and June was the critical period of seedling growth and so well watering fertilization and pest control measures should be taken during this period.Through variance analysis and multiple comparison, there was no significant the growth law difference among the4poplar clones.(2)Compared the3black poplar clones and the control,the results showed thatthe four of poplar clones existed no significant differences in growth characteristic such as the height,D BH,volume.The sequences of DBH from high to law were followed:P. x euramericana cv.’Neva’>populus ’zhaiguanheiyangNO.1’>populus ’zhaiguanheiyangNO.2’>populus ’zhaigu anheiyang NO.11’.The height followed:populus’zhaiguanheiyangNO.1’> populus ’zhaiguanheiyang NO.2’>P.xeuramericanacv.’Neva’>populus ’zhaiguanheiyang NO.11’.The volume followed:P. x euramericana cv.’Neva’>populus’zhaiguanheiyang NO.1’>populus ’zhaiguanheiyang NO.2’>poopulus ’zhaiguanheiyang NO.11’. The bark volume followed:narrow crowns poplars less than P. x euramericana cv.’Neva’form factors changes between0.08-0.36.The sequance are factor followed:populus’zhaiguan heiyang NO.11’ >populus ‘zhaiguanheiyang NO.1’>P.×euramericana cv.‘Neva’>populus ‘zhaiguanheiyangNO.2’.(3)The study of poplar clones’growth model showed that height,growth,DBH growthand volume growth appeared to the ‘fast-slow-fast’ growth rhythm,and it might be wellexpressed by Logistic(R2=0.945P<0.01). K value different with clones.The height limitvalue of populus‘zhaiguanheiyang NO.1’ was biggest in all clones,it was20.349m,followedpopulus‘zhaiguanheiyang NO.2’ with the P.×euramericana cv.‘Neva’.populus ‘zhaiguanheiyang NO.11’ was the smallest.The DBH limit value of P.×euramericana cv.‘Neva’wasbiggest in all clones,it was36.643cm, populus‘zhaiguanheiyang NO.11’ was the last.Thevolume limit value of P.×euramericana cv.‘Neva’ were biggest in all clones,it was0.105m3,populus ‘zhaiguanheiyang NO.2’ was the last,there was no significant different among thedifferent growth period by the equation.(4)The whorled branches reasearch results showed that vertion are P.×euramericana cv.‘Neva’ was the last. Average diameter of the first lateral branches from stem ofpopulus‘zhaiguanheiyang NO.1’ was1.402cm, populus‘zhaiguanheiyang NO.2’ was1.308cm,populus‘zhaiguanheiyang NO.11’ was1.336cm, P.×euramericana cv.‘Neva’ was1.57cm. Average branching angle first lateral of branches were populus ‘zhaiguanheiyangNO.1’was40.33°, populus‘zhaiguanheiyang NO.2’ was38.17°, populus‘zhaiguanheiyangNO.11’ was38°,P.×euramericana cv.‘Neva’was44.67°. populus ‘zhaiguanheiyang NO.1’there were maximum distance between trunk the first whorled branche is73.5cm with theangle of16°. populus ‘zhaiguanheiyang NO.2’ there were maximum distance between trunkthe first whorled branche is66.2cm with the angle of12°. populus ‘zhaiguanheiyang NO.11’there were maximum distance between trunk the4th whorled branche is60.8cm with theangle of17°. P.×euramericana cv.‘Neva’ there were maximum distance between trunk thesecond whorled branche is75.7cm with the angle of21°.(5)Net photosynthetic rate(Pn) of the4poplar clones was in a fine day in August, oncuve,the first(bigger) peak reached at9:00,and the second (smaller) at15:00. The transpirationrate were same with the net photosynthetic rate. The apparent quantum efficiency(AQE) ofthe4poplar clones showed: populus ‘zhaiguanheiyang NO.1’ was the biggest. Populus‘zhaiguan heiyangNO.2’,P.×euramericana cv.‘Neva’were second, populus ‘zhaiguan heiyangNO.11’ was the last.The water use efficiency showed: populus ‘zhaiguanheiyang NO.1’wasthe biggest. populus‘zhaiguanheiyang NO.2’,P.×euramericana cv.‘Neva’ were second,populus‘zhaiguanheiyang NO.11’ were the last.The saturation points of the4poplar clones of populus‘zhaiguanheiyang NO.2’ were the biggest.populus‘zhaiguanheiyang NO.1’,P.×euramericana cv.‘Neva’ were second, populus‘zhaiguanheiyang NO.11’ were the last.(6)Biomass allocation of above-ground parts followed:stem>branches>root.4clonesbiomass seqaecet were P.×euramericana cv.‘Neva’> populus‘zhaiguanheiyang NO.1’>populus ‘zhaiguanheiyang NO.2’> populus‘zhaiguanheiyang NO.11’,root biomassfollowed:P.×euramericanacv.‘Neva’>populus‘zhaiguanheiyangNO.2’>populus ‘zhaiguanheiyang NO.1’>populus‘zhaiguanheiyang NO.11’.The highly significant correlation between theconcentration average crown diameter and biomass of the P.×euramericana cv.‘Neva’ andpopulus‘zhaiguanheiyangNO.2’.Thealsobiomass and crown length of populus ‘zhaiguanheiyang NO.2’ no significant correlation single tree biomass and crown form ratio.The populus‘zhaiguanheiyang NO.11’ had highest root-shoot ratio, P.×euramericana cv.‘Neva’ werelowest.