Articles
THE EFFECT OF CALCIUM CYANAMIDE ON BUDBREAK, RETRANSLOCATION OF ACCUMULATED 14C-ASSIMILATES AND CHANGES OF NITROGEN IN GRAPEVINES IN TAIWAN
After pruning in February of the following year, the short canes were treated with leaching solution of calcium cyanamide or nicking plus ethylene chlorohydrin as budbreak forcing chemicals to evaluate their effects on the retranslocation of accumulated 14C-assimilates from storage organ to newly developed shoots.
The percentage respiratory consumption of 14C in roots and new shoots were evidently higher for both of the treatment of nicking plus ethylene chlorohydrin and untreated vine.
The maximum percentage retranslocation of 14C in new shoots were 21, 10 and 14 per cent respectively for the treatments of calcium cyanamide, nicking plus ethylene chlorohydrin and untreated control.
Similar results were also observed in the investigation of total carbohydrates utilization.
In another experiment, when these budbreak forcing chemicals were treated on the field vines, the beginning of budbreak was 40 days earlier, and the per cent of budbreak was 50 per cent higher than that of untreated control.
During the period 15 days after treatment (just before budbreak), calcium cyanamide caused a rapid increase of each insoluble nitrogen and soluble nitrogen content in buds and roots.
In the vine after nicking plus ethylene chlorohydrin treatment, the content of insoluble nitrogen in buds, and soluble nitrogen in buds and roots also increased slightly until the day just before budbreak, but insoluble nitrogen in roots showed a sharp increase on the 7th day after treatment, then decreased rapidly on the day just before budbreak.
While untreated control vines showed no significant change in nitrogen content.