Analysis On The Restricted Factors And Yield Strategies On Xanthoceras Sorbifolium In Western Of Liaoning

Yellowhorn(Xanthoceras sorbifolium Bunge)is an oil-bearing tree native to northern China.Though with economic and ecological importance,much lower yield resulting from poor conserved fruits has blocked its development in the industrial scale.The paper based on the soil condition in the western area of Liaoning Province,studied such little mentioned befor fators as the contents of non-structural carbohydrate(NSC)in the four apical growing parts of plant,the measures to improve tree body growing quality,and the pollination characteristics during flowering,and so on.The main results are as follows:1.The contents of soluble sugar and starch(together as NSC)in the four organs of yellowhorn were determined,which include biennial branches,annual shoot,inflorescence(blooming into fruit shoot later)and leaves.Data shows that the soluble sugar content is fairly consistent with that of starch at different phenological stages.Before leaves exhibited which accur on flowering top bud germination mainly consumes the concerved NSCs in vivo.With leaves fullfilled and blosooming all the four organs simultaneously accumulate photosynthesized NSCs to a higher point,then,from ovary enlargement to fruit formation almost of all the accumulated and subsequently producted NSCs was shifted to transport to the fruit developing side for the need of rapid enlargement.During this stage there are great amount of growing fruits dropped in succession,and both soluble sugar and starch contents in the four organs fall into as the very low levels as the beginning of flowering.After that,the remained fruits no longer enlarged,the NSCs are once again restored enrichement till fruits harvested.This pattern of NSCs implies that greater attention to the NSCs contents changes at the two turning points,both the time of flowers emerging and the end of fruits dropping,may help maintain or enhance fruit and seed production in yellowhorn.Trying to prevent NSCs from consumed too much at the time of ovary enlargement span to fruit formation may be a criterion for evaluating whether the management measures of yellowhorn are fully available.2.Based on the soil background in western of Liaoning,the Box-Behnken Design(BBD)experiment was conducted to study the effect of artificial measures(such as watering,fertilizing and pruning)on fruit yield.The optimized condition for fruits was treated as each tree being watered 13.31 kg;fertilizer 0.32 kg,and pruning branches to the degree of moderately sparse canopy,and showed an increased seed yield by 0.346 kg(n=24).Of course,the above conclusions are confined to the western Liaoning artificial planting yellowhorn,the reasonable and applicable guide for the production of yellowhorn fruit including the establishment of the response surface model should be treated according to the actual situation.3.It has long been controversial for yellowhorn that the method of pollination is through wind or insect.This work,by means of isolating insects from fertilization,proved yellowhorn is most probably an entomophilous ones and anemophilous gives little contribution.Assisted bee stocking can dramatically promote its fruit setting rate.In windy spring the prevailing wind direction on the bee activites should not be ignored as seed production to upwind increased by 32.58%(p< 0.05)in the yellowhorn plantation compared with that to downwind.Another factor that should be concerned is temperature because the lower flowering temperature could depress insect pollinator's activities,making flowers futilized insufficient,and sutting the bee pollination distance as short as to 210 m from the stocking position.Based on these reasons the suggestion of when assisted pollination by bees placing the hive at a distance of 100 meters and paying attention to the selection of low temperature bee species was proposed.Though the above conclusions were made preliminary success they may be benifficial to solving the problem of low yield for yellowhorn,including those implementation of moderate irrigation,fertilizer and pruning operations,as well as hardy bee's help.