Pre-sowing treatments for improving emergence of bitter gourd seedlings under optimal and sub-optimal temperatures

Pre-sowing treatments for improving emergence of bitter gourd seedlings under optimal and sub-optimal temperatures

2001

A:PS

Bitter gourd (Momordica charantia) requires high temperature (between 25 and 28øC) for successful seedling emergence, and poor emergence is common at sub-optimum temperature. This study evaluated the effect of sub-optimum temperature on seedling emergence and several physiological characteristics related to seedling growth in bitter gourd cv. Special Six. Priming was achieved by mixing the seeds with moist No. 3 vermiculite, incubating at 25øC for 36 h, then air-drying to the original moisture level. Warm water soaking was achieved by soaking the seeds in water at 50øC for 60 min, and then air-drying to the original moisture level. Seedling emergence from vermiculite was determined at 25, 20 and 15øC. The emergence of non-treated seeds at 25øC was 50%. No seedlings emerged at 20 or 15øC. However, both priming and warm water soaking improved the emergence responses of bitter gourd seeds under 25 and 20øC. The observed decrease and delay in emergence at sub-optimum temperature were linked to the reduced activity of enzymes (i.e. isocitrate lyase, malate synthase and malate dehydrogenase) involved in lipid and sucrose conversion. Both priming and warm water soaking improved the low temperature (20øC) seedling emergence. These improvement were attributed to the increased enzyme activities. Nevertheless, the morphological changes and softening in seed coat and seed treatment-stimulated embryo growth might also play crucial role in speeding up the seedling emergence.

v.29(1):39-50, SEED SCIENCE AND TECHNOLOGY

Research > Published Articles