Physiological, isozyme changes and image analysis of popcorn seeds submitted to low temperatures

Alterações fisiológicas, isoenzimáticas e análise de imagens de sementes de milho pipoca submetidas a baixas temperaturas

Abstract:

This present study aimed to assess seed quality of popcorn seedlings subjected to low temperatures by examining their physiological changes, enzymes, and images. We used a completely randomized design with four replications in a factorial arrangement with four hybrids (P618, AP6002, AP8202, AP8203) and five temperatures (10, 13, 16, 19 and 25 °C). Their physiological quality was assessed through radicle protrusion, germination, dry mass of seedlings and emergence. We have assessed the images of seedlings through their hypocotyl and root lengths; and through rates of automatic force, uniformity and growth, provided by Groundeye. The isozyme expressions were determined for the catalase (CAT - IUBMB: EC 1.11.1.6), alcohol dehydrogenase (ADH - IUBMB: EC 1.1.1.1), malate dehydrogenase (MDH - IUBMB: EC: 1.1.1.37) and α-amylase (α-AMY - IUBMB: EC 3.2.1.1). Results show that low temperatures cause a negative effect on seed physiological quality in enzyme expression of CAT, ADH, MDH and α-AMY and on the performance of seedlings. These alterations compromise seed quality. Hybrids AP6002 and AP8203 should be recommended for sowing at up to 16 °C. The Groundeye software was efficient in the analysis of popcorn seedlings and in for the assessment of seed quality when submitted to low temperatures.

Index terms:
Zea mays; seed quality; Groundeye; enzyme; cold