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Embryo Drying Rates during the Acquisition of Desiccation Tolerance in Maize Seed
Author(s) -
CordovaTellez Leobigildo,
Burris Joseph S.
Publication year - 2002
Publication title -
crop science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.76
H-Index - 147
eISSN - 1435-0653
pISSN - 0011-183X
DOI - 10.2135/cropsci2002.1989
Subject(s) - desiccation , biology , desiccation tolerance , zea mays , embryo , germination , zoology , horticulture , airflow , water content , botany , agronomy , microbiology and biotechnology , geotechnical engineering , mechanical engineering , engineering
Maize ( Zea mays L.) seed quality is often reduced because of drying injury, although the causes and impairment mechanisms are poorly understood. In this study, we investigated changes in embryo drying rates and their effect on the acquisition of desiccation tolerance in maize seed. Ears of hybrid maize [B73 × (H99 × H95)] were harvested at about 550, 500, 400, and 320 g H 2 O kg −1 fresh weight (fw) and subjected to preconditioning (PC) (ear drying at 35°C and 0.47 m s −1 airflow rate) for 0, 12, 24, 36, and 48 h before fluidized bed (FB) drying (shelled seed, 35°C and 5.10 m s −1 airflow rate) treatments to decrease moisture content (MC) to about 130 g H 2 O kg −1 fw. Additionally, ears were entirely dried under PC (35C) and unheated‐air (NH) conditions. At the four harvests, different drying rate phases were evident in embryos of seed dried entirely at PC (35C) conditions. A slower drying phase coincided with the PC period, which increased with increasing maturation. Under FB drying, embryo MC declined at a faster rate down to about 400 g H 2 O kg −1 fw, followed by an intermediate drying rate down to about 200 g H 2 O kg −1 fw, and a slower drying rate below this point. As embryo MC declined to 400 g H 2 O kg −1 fw at slower drying rates, either with PC or field drying, the ability to withstand the faster drying rates of the FB progressively increased. This effect was illustrated by lower cell solute leakage and better performance in germination and vigor tests. We conclude that slow embryo drying rates to threshold levels may be crucial to acquire their ability to withstand higher drying rates without detrimental effect on seed germination and vigor.