A study of the effect of environmental factors on the growth and development of the lowbush blueberry was carried out using clonally propagated plants. In a preliminary study a definite photoperiodic response was found. Under 8-hour days flower buds were formed and no vegetative growth occurred. Under 16-hour days vegetative growth resulted and no flower bud formation occurred. In a replicated greenhouse experiment, seven clones produced flower buds with 8-, 10-, and 12-hour days, but produced none with 14- or 16-hour days. One clone produced flower buds with 8-, 10,- 12-, and 14-, but none with 16-hour days. Two clones were able to produce flower buds under all five photoperiods. Under 8- and 10- hour photoperiods no vegetative growth occurred. Under 12, 14, and 16 hours progressively more vegetative growth occurred. In an experiment on the interaction of temperature and photoperiod, vegetative growth was significantly greater at 70° F than at 50° F with the differences being accentuated by day length. Flower bud formation occurred with 11- and 13-hour photoperiods regardless of temperature, but was more pronounced at the higher temperatures. At 70° F, 15-hour photoperiod, no flower buds were formed while at 50° F, 15 hours, three clones produced no flower buds and six clones produced an abnormal type of inflorescence. Similar abnormal inflorescences were produced by giving plants 2, 3, or 4 weeks of 8-hour days. Six weeks of 8-hour days was sufficient to initiate normal inflorescences. Shade, provided by two layers of cheesecloth, significantly reduced the number of flower buds compared with full sunlight. The growth of the lowbush blueberry under field and laboratory conditions is discussed in relation to environmental factors.
The fuzzy logic accepts infinite intermediate logical values between false and true. In view of this principle, a system based on fuzzy rules was established to provide the best management of Catasetum fimbriatum. For the input of the developed fuzzy system, temperature and shade variables were used, and for the output, the orchid vitality. The system may help orchid experts and amateurs to manage this species. "Low" (L), "Medium" (M) and "High" (H) were used as linguistic variables. The objective of the study was to develop a system based on fuzzy rules to improve management of the Catasetum fimbriatum species, as its production presents some difficulties, and it offers high added value. RESUMOA lógica fuzzy admite infinitos valores lógicos intermediários entre o falso e o verdadeiro. Com esse princípio, foi elaborado neste trabalho um sistema baseado em regras fuzzy, que indica a melhor forma de manejar a espécie Catasetum fimbriatum. O sistema fuzzy desenvolvido teve como entradas as variáveis temperatura e sombreamento, e a saída à vitalidade das orquídeas, que poderá auxiliar os orquidófilos no manejo da espécie, e foram utilizadas as variáveis linguísticas "Baixo" (B), "Médio" (M) e "Alto" (A). O objetivo deste trabalho é desenvolver um sistema baseado em regras fuzzy para auxiliar no manejo da espécie Catasetum fimbriatum, pois se trata de uma espécie de difícil cultivo e de alto valor agregado.Palavras-chave: Manejo, cultivar, habitat e sistemas Fuzzy
The production of toxic substances by Helminthosporium sativum P.K. & B. on a variety of artificial media was evaluated by means of a barley seed germination test. The results suggest that these substances also limit the growth of the organism itself giving a fixed maximum level of toxin production. Destruction of toxin and renewed production continue until some other factor of the medium limits further growth, and culture filtrates then rapidly become inactive. The toxins are relatively nonspecific and appear to affect susceptible hosts by conditioning them to invasion by the organism. A loose correlation was found to exist between toxin production and pathogenicity in a limited number of Helminthosporium strains. Even in the presence of abundant toxin, however, these strains differed in their ability to invade barley seedlings indicating that factors other than toxin production were also involved in pathogenicity.
A standard sand – cornmeal – nutrient salt medium, for use in the production of artificial inoculum of Helminthosporium sativum, is described. This inoculum induces uniform plant disease development when thoroughly incorporated with the planting soil. The results presented clearly demonstrate the necessity of using a series of infestation levels in studies of factors affecting disease development in artificially infested soil. It is shown that considerable reliance can be placed on treatment comparisons within an experiment but that comparisons between experiments are much less accurate. The role of a toxin (or toxins) in disease development in barley seedlings has been demonstrated. The toxic activity was found to be distinct from that frequently encountered on addition of organic matter to soil. Results obtained suggest that toxin adsorption by the soil may play an important role in reducing disease incidence and severity.
A crude aeration precipitate of nabam was found to possess a relatively high order of fungicidal activity. Evidence is presented to show that this activity can be attributed to ethylene thiuram nonosulphide, both monomer and polymer. This substance was demonstrated on the foliage of plants sprayed with nabam and could account for its protective fungicidal action.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.