บทคัดย่องานวิจัย

หมวดหมู่ : ฐานข้อมูลงานวิจัย

Soybean seed maturation, respiration, and preharvest deterioration

Ansoanuur, James Saanuorkuu.

Dissertation Abstracts International

1987

บทคัดย่อ

SOYBEAN SEED MATURATION, RESPIRATION, AND PREHARVEST DETERIORATION.

The objectives of this study were to monitor soybean seed maturation and postharvest seedling vigor in relation to (1) embryo tissue color changes, (2) changes in respiration rates, (3) changes in respiratory components, (4) changes in water content, and (5) to determine if exogenous additions of the antioxidant, alpha-tocopherol, which is known to block free radical formation would preserve seed vigor during delayed harvest from an in vitro medium conducive to accelerated aging.  Soybean (cv.  Chippewa 64) seeds of mid seedfill size (300 to 350 mg FW) were matured in situ and in vitro.

 

 Both in vitro and in situ, axes had higher relative water content, higher respiration rates, faster yellowing and earlier achievement of maximum dry weight than cotyledons.  Retention of high water content supporting higher respiration rates in axes for a longer duration than in cotyledons may be a primary cause of preharvest seed deterioration in soybean.  Dry matter accumulation ceased when 80 to 90% of the surface of cotyledons was visibly yellow.  Growth in medium with alpha-tocopherol and 146 mM sucrose delayed visual yellowing of cotyledons but did not increase seed dry weight or conserve postharvest seedling vigor.

 

 The decline in total oxygen uptake and oxygen uptake via the cytochrome pathway during seed growth were functions of increasing dry matter accumulation in embryo parts both in the greenhouse and in vitro.  Respiration rate in axes or the decline in the cytochrome pathway during seed maturation were not related to the postharvest expression of seedling vigor implying that mitochondrial activity may not be a reflection of seed quality.  Residual respiration, when expressed as a percent of total respiration increased with seed maturation while alternative respiration remained low at about 5% of total oxygen uptake both in vitro and in situ.  Yellowing of embryonic tissues was not correlated with lipoxygenase activity or with the decline of vigor of in vitro grown seeds.  Lipoxygenase activity contributed to total oxygen uptake, was higher in cultured embryonic tissues than in situ, and was the only oxygen uptake parameter which correlated with lowered postharvest seed vigor.  (Abstract shortened with permissi

 on of author.).