The ethyl forming enzyme in senescing leaf segments of rice cultivars differing in their responses to water stress.

Date

3-1990

Degree

Bachelor of Science in Biology

College

College of Arts and Sciences (CAS)

Adviser/Committee Chair

Arcelia A. Alejar

Abstract

Excised leaf segments from different rice cultivars varying in their degree of tolerance to water stress were used to determine a possible relationship between water stress-induced senescence and activity of the ethylene forming enzyme (EFE). The role of calcium as regulator of senescence was also assessed. The activity of EFE appeared to be higher in senescing leaves of sensitive cultivars than tolerant ones but was not significantly different. Treatment with mannitol or NaC1 (-0.5 mPa) gave a significant rise in ethylene production. Similar increase was detected in the presence of calcium. There was a faster rate of senescence observed in sensitive than in the tolerant cultivars, for both control and water stress or calcium treated leaves. This result suggests a possible criterion in screening for water stress tolerance in rice. The findings that calcium hasten senescence coupled with significant increase in ethylene production suggest that calcium is likely to induce EFE activity.

Language

English

Location

UPLB Main Library Special Collections Section (USCS)

Call Number

Thesis

Document Type

Thesis

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