Abscisic Acid Levels in Seeds of Peach. II. Effects of Stratification Temperature1

Cold requirement for germination of excised ‘Kakamas’ peach (Prunus persica (L.) Batsch) embryos was satisfied after 2 weeks at 4.4°C; embryos with testas intact required 4 weeks, while seeds with intact endocarps required 12 weeks stratification. Leaching of unstratified excised embryos stimulated germination. The endocarp affected germination by delaying water uptake. Supplying additional O2 during stratification or germination of seeds with intact endocarps did not improve germination. Cracking the endocarps stimulated germination of stratified seeds, but sealing the cracks with lanolin paste prevented this effect. The endocarps may interfere with the leaching of inhibitors from the testa and embryo. Initial seedling growth of embryos with or without testas increased linearly with increasing time of stratification in terms of shoot length, dry weight of shoots and leaves, dry weight of roots and leaf area, length and width. Seedlings arising from embryos with intact testas were taller and had a greater dry mass of shoots, leaves and roots compared to seedlings arising from embryos without testas.

Section: Resultssupporting

confidence: 58%

“…-----------------and R. W. Langhans. 1969 Considerable attention has been given to the role of the embryo and testa in the dormancy of peach seeds (1,2,4,5). During stratification there is a decrease in free abscisic acid 1 Received for publication November 10, 1978.…”

mentioning

confidence: 99%

Role of the Various Seed Parts in Peach Seed Dormancy and Initial Seedling Growth

Toit

Jacobs

Strydom

1979

“…However, few in vestigators have included controls held at temp which do not break dormancy. Where this has been done, the changes in ABA have generally been found to be independent of temp (2,20). Therefore, a question has been raised as to the role of this com pound in dormancy.…”

mentioning

confidence: 99%

Abscisic Acid and Apple Seed Dormancy1

Dennis

1977

Self Cite

c,t-Abscisic acid (ABA) was identified in methanol extracts of mature apple (Malus domestica Borkh.) seeds by gas chromatography-mass spectrometry, and concentrations of both free and base-hydrolyzable (bound) ABA in immature and mature seeds were quantified by electron capture gas chromatography. Immature embryos failed to germinate regardless of time of sampling unless seed coats were removed. Germination of excised embryos reached a maximum in early August, then gradually declined to nil in mid-September. Although ABA content of the embryonic axes rose sharply at maturity, the rise occurred only after germination capacity declined. Premature defoliation reduced ABA content of the axes, but did not prevent the induction of embryo dormancy. ABA content of mature seeds declined during stratification at both 5° and 20°C, with maximum differences occurring in the embryonic axis, but dormancy was broken only at 5°. Induction of secondary dormancy by high temperature (27°) was accompanied by a slight decline in ABA content of whole seeds.

“…Removal of the testa did not increase the correlation, although some increase was expected by removing the maternal influence of the seed coat. Indications that the role of the testa in germination is more of a physical nature than a chemical one can be drawn from data presented by several authors (1,2,7).…”

Section: Resultsmentioning

confidence: 99%

“…An additional group of 10 families, including crosses and OP families, was included in this study, but their testae were removed. Previous reports indicate that germination inhibitors present in the testa lengthen the CR of the embryo (1,2,3,4 9). Seed were examined every 5 days once germination started.…”

Section: Methodsmentioning

confidence: 99%

Relationships between Parental, Seed, and Seedling Chilling Requirement in Peach and Nectarine

Rodriguez-A.

Sherman

1985

Attempts to select for flower bud chilling requirement (CR) at the seed stage were made in 58 families obtained from crosses and open-pollination of low chill selections and cultivars of peach and nectarine [Prunus persica (L.) Batsch] from the Florida breeding program. A nonsignificant correlation (r = 0.08) between midparent bud CR and family seed CR was obtained. A low significant correlation (r = 0.21**) was obtained between individual seed CR and the CR of the resultant seedling. Seed coat removal had no effect on these correlations. Narrow sense heritability for bud CR as determined by parent-offspring regression was 0.50 ± 0.06. The small range in CR of the seed and pollen parents, 300 to 450 and 200 to 400 chill units, respectively, may explain the low correlation values obtained. The data suggest that it is impractical to screen for seedling CR based on seed CR where the CR for climatic adaptability must be held within a range of less than 300 chill units.