VARIATION OF REDUCING AND TOTAL SUGARS DURING GROWTH OF ONION TISSUES

Bulb formation is influenced by photoperiod and temperature. Mature onion plant is composed of 60-80% dry matter of non-structural carbohydrates as well as a series of oligosaccharides. Sugars are very important in the response to these stimuli, and are also involved in carbohydrate status of the plant, as well as the keepability of onion bulbs after harvest. In this experiment, reducing and total sugars in three different regions – shoot, neck and tissues bulb of the onion plant were assessed during different growing and bulbing stages. Reducing sugars were assessed using the Nelson and Somogyi’s method, and total sugars were determined by starch hydrolysis, thereafter the application of the Nelson and Somogyi’s determination of reducing sugars. Onion seeds were directly seeded in pots and placed in a greenhouse at the University of the West Indies, monitored and data collected. Results showed that total and reducing sugars accumulate in the leaves and translocated massively when bulbs formed.