Showing papers in "Seed Science and Technology in 1980"

Germination, dormancy and morphology of the seeds of herbaceous ornamental plants

Abstract: Eight basic forms of seed structure are described. The seeds of species within each form have been found to have similar dormancy and germination patterns. Seed with rudimentary and linear embryos require time for further maturation of the embryo before germination. Miniature seeds require light at the beginning of the germination period. Seeds with peripheral embryos are protected by inhibitors in multiple seed coverings which need to be removed or leached before germination. Non-endospermic seeds or seeds with residual endosperm have mature embryos which are ready to grow but growth is blocked by their seed coverings. Hard seed coats which restrict the imbibition of water require mechanical or chemical abrasion or a release through the hilum, chalaza or strophiole. Seeds having a mucilaginous exudation exclude oxygen and may require light, low temperature or the addition of gibberellic acid. Seeds with multi-layered woody and fibrous seed coats are semi-permeable, allowing water entry but blocking oxygen and retaining strong inhibitors. Extracted embryos grow readily. Various permeability aids are necessary including temperature alternation, KNO(,2), light and abrasion. An understanding of these structural blocks to germination and the modifying effects of environment is directive in establishing methods for germinating flower seeds.

Relationship of Vigour Tests and Seed Lots to Cotton Seedling Establishment

Abstract: Two seed lots of cotton (Gossypium hirsutum) were artificially deteriorated to provide sub-lots with high viability but a range of seed vigour. Standard germination of the sub-lots ranged from 72.0 % to 92% and averaged 82.7 %. The cold test results of non-deteriorated seeds were closely related to standard germination results in both seed lots, but averaged 24 and 27 percentage points lower respectively in medium and low quality seeds. The results of accelerated-ageing root length after three days, Q 0 2-uptake and conductivity tests also showed significant differences between different quality levels as well as between lots. The results of the vigour tests (except conductivity) were significantly correlated with seedling establishment in the field. High quality seeds emerged more rapidly and produced a higher final seedling establishment than deteriorated seeds. Seeds of hand picked and laboratory ginned lots were of better quality than mechanically harvested and commercially ginned seeds.

Coleoptile length in sorghum.

Abstract: Coleoptile growth in 10 sorghum cv. was studied on paper towel, sand or soil media. Cv. differences were seen in the character but it was influenced by radicle growth in sand and soil media. Coleoptile and radicle length had a negligible negative phenotypic correlation in paper towels but a considerable positive association was recorded in sand and soil. A difference in sowing depth in the field did not have a significant effect on germination count