Effect Of Bulb Storage On Flowering Of Tulip

The tulip(Tulipa gesneriana L.)is the most famous flowering bulb in the world.In China,large amount of tulip bulbs are imported every year for garden landscape.However,the difference of climate between China and the production country results in the inability of the bulbs growing very well.At the same time,the condition of the florescence changes with the temperature every year.In Beijing,most tulip cultivers can not bloom well in early May.Manpower and material resources are wasted in using potted tulips to solve the problem.It is convenient if we can retard the flowering by planting in spring after storing bulbs.By extensive observation of the ornamental chracteristics of 32 tulip cultivars grown in Zhongshan Park,Beijing,'Ile de France' and 'Parade' were selected for storing.Some indexes were measured for studying the physiological processes during storage.The conclusions reached include the followings:Tulip starts to grow quickly when the maximum mean air temperature reaches 17～21℃and the maximum mean soil temperature reaches 13～15℃in spring of Beijing.The 32 tulip cultivars showed similar characteristics of growing and all of them can grow and bloom normally,among them 15 cultivars such as 'Alba','Monte Carlo','Makassar' and 'Ile de France',etc.,grow and bloom very well.'Ile de France' and 'Parade' were selected as material for studying the changes of physiological property including starch contents,protein contents,total sugar contents,POD activities and SOD activities.The results show that starch and sugar contens change apparently during the low temperature storage.Starch contents decreased continuously and total sugar contents had a process from increasing to decreasing during storage.Nutrients are consumed mostly by bud and root growing.The ornamental characteristics of the stored bulbs are different from that of the normal planted bulbs in the autumn.In general the plant height and the diameter of the flower decreased,and showed uneven growth among the replicates.The results also show that stored bulbs can not root well in spring at temperatue below 0℃,however the 2℃storage retarded the blooming of 'Ile de France' for a certain extent and the ornamental appearance is accepted for landscaping.