Seed development and vivipary in Zea mays L.

Area of Science:

• Plant Physiology
• Molecular Biology
• Seed Development

Background:

• Seed development involves dehydration and dormancy, crucial for plant survival.
• Abscisic acid (ABA) plays a key role in regulating these processes.
• The viviparous (vp-1) mutant in Zea mays exhibits defects in seed maturation and dormancy.

Purpose of the Study:

• To investigate seed development in wild-type and viviparous (vp-1) Zea mays.
• To determine the role of abscisic acid (ABA) in seed desiccation and germination.
• To compare the responses of wild-type and vp-1 embryos to ABA and water-deficit stress.

Main Methods:

• Comparative analysis of wild-type and vp-1 Zea mays kernel development.
• Quantification of endogenous abscisic acid (ABA) levels in embryos and endosperm.
• Excision and treatment of embryos with ABA and mannitol to assess germination and growth.

Main Results:

• Viviparous (vp-1) embryos failed to desiccate, accumulating fresh weight through coleoptile growth.
• Endogenous ABA levels were similar in wild-type and vp-1 tissues, declining during development.
• Excised vp-1 embryos showed reduced sensitivity to ABA and mannitol-induced growth inhibition compared to wild-type.

Conclusions:

• The vp-1 mutation affects seed development by altering responses to ABA, not ABA biosynthesis.
• ABA is critical for desiccation and preventing precocious germination in Zea mays.
• Viviparous (vp-1) seedlings exhibit altered physiological responses to ABA and water stress.