Research On 'TianHuang' Pear Tree, The Growth And Development Characters Of Fruit And Mineral Nutrition

'Tianhuang' pear is a new pear cultivar introduced from Korean.Through field test and observation,component analysis of mineral nutrition,paraffin section anatomise,the paper made a systematic observation and study on the process of 'Tianhuang' pear shoots, leaves and fruits,formation and development of flesh,contents changes of mineral elements in leaves and fruits in an annual cycle.The main results as follows:(1) The growth fruits of 'tianhuang' pear shoot were:new long shoot was very long and averaged 70.29cm,bud was filled,but flower bud rate was rather low and had only34.18%, flower bud mostly located in the middle and top of shoot. Fruit setting percentage is 61.67%.The amounts of shoot and the whole length of new shoot among short-shoot,middle-shoot and long-shoot were greatly different. Short shoots which majored in fruiting had minimal growth increments,while long-shoots had maximum growth increments and accounted for 85.63% of the whole growth increments. 'Tianhuang' pear had two shoot growth types:one-time growth and two-time growth.The former growth duration was more shorter,and formed short and middle shoot finally; The later growth duration was more longer,and formed long shoot finally. The formatoin of leaf curtain was in early May.The correlation between new-shoot and leaf was no significant difference.(2)The growth and development fruits of tianhuang'pear were:'tianhuang' pear came into full bloom stage in the end of March and the stage of fruit ripening was in early and middle September,and the growth cycle was about 150d to 175d in zhuzhou. The average daily diameter and length accumulated of 'tianhuang' pear had three growing tops.In first growing top,mesocarp cells rapidly divided and the number of cell increased widely,and cells were more smaller and densely arranged,each several part of cell was no significant difference,volume and weight of fruit increased slowly; In second growing top,volume of flesh cells expanded fastly at different speed.Flesh cells increased gradually from outer to inner. Volume and weight of fruit increased quickly; In third growing top, volume of flesh cells continued to expanded and inner contents accumulated. Weight and quality of fruit were at better state.Fruit sclereids began to develop early.and per sclereid appeared in 12,December,and the number of sclerid group retained stable in early July. Embryo began to develop in early April, and there were six stages during the development of embryo,including two celled proembryo, cdub-like proembryo, globularl proembryo,ect. Mature embryo formed in early June,which had germ,hypocotyl,randicleand cotyledons.(3)The process of 'tianhuang' pear fruit growth and development and volume and weight of fruit were all significantly positive correlated. Equation of linear regression between the process of fruit growth and volume is Y=-133.499+4.418X, equation of linear regression between the process of fruit growth and weight is Y=-134.138+4.435X. Diameter and length of fruit and volume are significantly positive correlated,their equation of linear regression isY=-155122+7651.395X1-907.398X2(diameter is X1,length is X2, volume isY)(4) Annual changes features of mineral elements in leaves of 'tianhuang' pear were:Contents of several mineral,including N,P,K,Mg in leaves were the maximum in small fruit stage, and reached the lowest level during ripening stage,while, Contents of Ca was the minimum in small fruit stage, and reached the highest level during ripening stage, N and Ca had larger variation and other minerals kept in a constant level.The sequence of 5 mineral elements contents in leaves was Ca>N>K>Mg>P in late September. There was very significant negative correlation between Ca and N,P,K and Mg in leaves, and there was significantly positive correlation between N,P,K and Mg. The optimal sampling period of leaf analysis was from the end of June to middle July.(5) Annual changes features of mineral elements in fruits of 'tianhuang' pear were:Contents of N,P,K,Ca,Mg in fruit were gradually decreased from young fruit stage to ripening stage. N and K had larger variation,while P,Ca,Mg kept in a constant level.The sequence of 5 mineral elements contents in fruit was K>N>P>Mg>Ca in ripening stage.There was very significant positive correlation between N,P,K, Ca and Mg during the process of fruit growth. Contents of N,P,K,Ca and Mg in per fruit were gradually increased at certain stage,while their accumulation in small fruit stage were lower than it in middle and later fruit growth.Contents of K in per fruit always increased positively and other four mineral elements had negative increase during the process of fruit growth and development. The top stage of absorbing N,P,K,Ca and Mg in 'tianhuang' pear fruit was about in 75 days after blossom(14,June).(6)There was very significant positive correlation between N,P,K,Mg in leaves and fruits,while Ca was significantly negative correlated. The process of fruit growth and development and Ca in leaves were significantly positive correlated,and N,P,K,Mg in fruit and leaves were significantly negtive correlated. There was very significant correlation in five mineral elements in leaves and fruits and per fruit weight,the correlation between five mineral elements in leaves and per fruit weight was better.