ศูนย์นวัตกรรมเทคโนโลยีหลังการเก็บเกี่ยว

Respiration, soluble carbohydrates and enzymes of carbohydrate metabolism in tips of harvested asparagus spears.

Irving, D. E. and Hurst, P. L.

Plant Science (Limerick) Year: 1993 Vol: 94 Issue: 1-2 Pages: 89-97 Ref: 36 ref.

1993

บทคัดย่อ

Asparagus officinalis (cv. Limbras 10) spears were held at 20 deg C for up to 5 days after harvest and changes in respiration rate, soluble carbohydrates and the activities of enzymes concerned with glycolysis and carbohydrate breakdown in the tips were examined. Respiration rate declined after harvest, to reach 25% of its initial rate after 2 days. The gas exchange (respiratory) quotient was 1.05 at harvest and declined in parallel with respiration rate for 2 days. There was a rapid loss of sucrose from spear tips over the first 6 h, followed by a more gradual loss. Glucose concentration declined gradually throughout, but fructose concentration barely changed over 3 days. It is concluded that a major change in the metabolism of Asparagus spear tips occurs soon after harvest, characterized by a switch from sucrose-derived hexose phosphate to another primary respiratory substrate, probably derived from protein and/or lipid. The activities of hexokinase, fructokinase, phosphofructokinase, sucrose

synthase and alkaline invertase [ beta -fructofuranosidase] were generally low compared with the activities of the other enzymes assayed. Overall, enzyme activities declined over 5 days of starvation. The exceptions were hexokinase, phosphofructokinase and pyruvate kinase, where activities were reasonably constant.