. Asymbiotic seed germination and in vitro seedling development of Nothodoritis zhejiangensis . ( A ) Flowering specimen of N. zhejiangens growing on the tree branches of Cornus officinalis . ( B ) Seed germination and protocorm development in vitro. ( C
Paper no. 20,823 of the Scientific Journal Series, Univ. of Minnesota Agricultural Experiment Station. The cost of publishing this paper was defrayed in part by the payment of page charges. Under postal regulations, this paper therefore must
Abstract
Germination of Maranta leuconeura E. Morr. embryos was 65% in Linsmaier and Skoog culture medium and increased to 100% with the addition of N6-[Δ2-isopentenyl] - adenine (2iP).
Seeds from mature seed pods of Cypripedium calceolus var. parviflorum were germinated on 1/4 MSMO (Sigma) + 100ml/l coconut water + 1% sucrose +/- 8g/l agar (pH 6.0), and with or without prechilling at 5C for 8 weeks. Protocorm with apex (stage 3) was use as an index of germination. Seeds sown on agar medium withou chilling treatment resulted in a 40% germination rate in 120 days but the germination was very uneven. Seeds germinated on agar medium with prechilling developed more synchronously with 92% germination in 60 days (ie. about 120 days after sowing). Suspension culture of seeds without prechilling resulted in 85% germination after 90 days. The synchronization of seed germination in suspension culture was intermediate between that on agar with and without prechilling. Protocorms germinated in suspension culture appeared morphologically identical to those germinated on agar medium. All stage 3 protocorms developed further on the same agar medium in darkness.
Both agar and suspension culture in media containing coconut water provided reliable seed germination methods for this orchid species.
., Baton Rouge, LA 70803. 4 Principal Research Specialist in Horticulture. Funds for this research were provided in part by the Illinois Agricultural Experiment Station. Special thanks to Gene Galletta and Adam Dale for their encouragement in this
Previous greenhouse studies in Raleigh have shown that nighttime cooling increases tomato fruit weights from 11% to 53%, depending on planting dates. The physiological mechanism was unclear, except that temperatures during fruitset were most critical. We report here on 3 experiments, 2 in greenhouses and 1 in the phytotron, comparing pollen characteristics of plants grown at differing night temperatures. In the greenhouse studies, nighttime temperatures were kept below 20°C for either the whole night or just the last half of the night. In the phytrotron studies night temperatures were 18, 22, 24 or 26°C, In both phytotron and greenhouse studies, there was considerable day-to-day variability in pollen characteristics and % germination. The most consistent effect in both types of studies was a decrease in total pollen and an increase in % abnormal pollen at high night temperatures. In the phytotron studies 20°C appeared optimal for both these characteristics.
1 To whom reprint requests should be addressed. Journal Article no. 249-90. Salaries and research support provided in part by state and federal funds appropriated to the Ohio Agricultural Research and Development Center and a Seed Grant to A.R. M
Abstract
Seeds of 29 terrestrial orchid species representing 15 genera were surface sterilized by immersion in 0.5% sodium hypochlorite containing a wetting agent, washed, sown on a completely defined, semisolid embryo culture medium containing macro- and microelements, sucrose, amino acids, and vitamins, and incubated in the dark at 25°C. Six months after sowing, 16 species from 9 genera germinated and continued development while 13 species from 10 genera failed to germinate. Species of Cypripedium, Goodyera, Platanthera and Spiranthes differed in response in that one or more of each germinated and one or more did not. Seedling development was similar for most germinating species and progressed to the formation of a shoot or shoot initial in all but one. Apparently the mycorrhizal association thought to be required for terrestrial orchid seed germination and early seedling development can be replaced with aseptic culture on a completely defined medium for many terrestrial orchids.
Abstract
Germination of freshly dehisced or partially dried 1-day-old pollen of lily (Lilium longifolium Thumb cv. Ace) was greatly enhanced by exposure to high humidity prior to inoculation in germination medium. Half the maximum response was obtained with 40% humidity or with 5 min humidifying time at saturation.