Studies On Propagation Performance Of Different Grades In Bulb And Physiological Changes Of Bulb During The Cold Storage

The tulips were introduced to our country successfully in the 1980s,and the cultivation area has been expanded in the past twenty years.However ,the the situation of introduction and cultivation throughout the country is that except in some areas, other areas are still consumptive cultivation,and there are some questions during the introduction and cultivation,for example tulip deterioration.In the researth,we selected high quality watierise which were good to propagate bulbs, studied the effecion of bulb grades on bulb propagation and assayed the physiological and biochemical indices during the cold storage, in order to provide the theory basis to the cultivation, propagation and storage of tulip. The conclusions reached include the followings:1.On the basis of previous result,we planted nine cultivars of tulip in Taibai,and after comparing the growth of plant ,bulb producting, starch content, soluble sugar content, soluble protein content and disease rate of bulb,we made a synthesis that Big Smile, Judith Leyster,Parade, G.Apeldoorn were high quality cultivars that were used to propagate bulbs in Taibai.2.Two varieties of tulip bulb which are Judith Leyster (Triumph tulips)and BigSmile(Darwin hybrid tulips), are compared in the experiment including the flower diameter after rankly planted,propagation coefficient, rate of yield. According to the statistic and analysis.The result revealed that with the grade of bulb enlarging,the the rate of weigh increase of the two varieties are first increased and then decreased ; Comparing to the two cultivars, the bu1b yie1d of Big Smile is higher than Judith Leyster's,but the propagation coefficients is low.For Judith Leyster,the bulb can bloom and propagate Grade I when the diameter are more than 3.272cm and 2.508cm respectively,as for Big Smile,it's over 2.5cm and 2.216cm,overall,we could conclude that Grade I,Grade II,Grade III of the two varieties could be used as a material for reproducing the commodity bulbs,and Grade IV,GradeV could be used to propagate daughter bulbs heavily.3.The effects of cold temperature on soluble protein content and carbohydrate composition were investigated in the bulb of Tulipa gesneriana plants.Four varieties of tulip bulb were stored at 5℃for 11 weeks. Starch content in bulb scales(outer and inner )of four varieties decreased during the storage ,but it rised again twice in some weeks,and Starch content decreased in 4～5 weeks continuously and dramatically, Compareing to starch content in scales,there was a lower content in central bud; Soluble sugar content in bulb scales(outer and inner ) increased continuously in 4～6 weeks, following an downward trend ,but it was maximun in 8th～10th, we proposed that it was one of physiological indices for the dormancy release.At the beginning of storage ,soluble sugar content in outer scales is higher, but the content was higher relatively in inner scales of Parade, Judith Leyster,Dordogne in the end. Soluble sugar content in central bud had an ascend trend,but it reduced in 8th; Soluble protein content in bulb scales(outer and inner ) rise again after a fall ,it was minimum in 6～7weeks and rised again. Soluble protein content in inner scales of other three varieties was higher than Big Smile at the end of storage.There was an ascend- downward trend in the central bud,that was higher than scales from sixth week to the end.