Search Results
You are looking at 1 - 5 of 5 items for
- Author or Editor: Christopher Ramcharan x
Preliminary experiments with uniconazole (UNZ) at 5- and 10-ppm sprays on Bird Pepper indicated that UNZ could be used to enhance appearance and improve fruiting of Bird Pepper, but some refinement of UNZ rates had to be made. Another experiment was conducted to determine rates of UNZ needed to maintain a suitable plant size with manual pinching and improve yield and total number of red fruit produced. Best overall effects were on plants single-pinched 4 weeks after sowing and treated with a foliar spray of 4 to 6 ppm UNZ. Higher UNZ levels produced too compact plants in which individual branches had to be staked. More-attractive double-pinched plants may be produced if UNZ application is delayed after the second pinch. Bird pepper can therefore be produced as a dual purpose pot plant by pinching followed by foliar applications of of UNZ preferably at 4 to 6 ppm.
Culentro, an umbelliferous aromatic saponin-containing biennial herb native of Central America and the West Indies is a major ingredient of many West Indian and Latin American dishes. Although closely related to the Asian culinary herb - cilantro or coriander, culantro is mainly prized for its green serrate spatulate-shaped leaves the main source of its oil. Like many other umbelliferoids under high temperatures and long summer days of the tropics culantro produces large umbel inflorescences and seedheads which are labor-intensive to remove, retard leaf growth and hence decrease the market value of the plant. Preliminary studies using ProGibb sprays from 50 to 200 ppm to 3- to 4-month old culantro plants grown under 53% shade showed increased leaf growth and chlorophyll content response to increasing levels of ProGibb. Maximum leaf length, fresh leaf weight, chlorophyll content and decreased flower growth were obtained at 100 ppm spray application. Treated plants remained in a vegetative phase for almost two years when vegetative side shoots were established. Postharvest observations showed no apparent decrease in shelf life nor loss of characteristic leaf aroma in leaves harvested from GA-treated plants. Inflorescences from sprayed plants were highly reduced in size, had leaf-like appearance and produced characteristic culantro aroma Indicating that they may also be utilized in culanto cuisines.
Abstract
Root systems of ‘Grande Name’ banana (Musa spp. L., AAA Group), Ixora coccinea L., Dracaena marginata L., and ‘Carrizo’ citrange [Citrus sinensis L. (Osbeck) × Poncirus trifoliata L.(Raf.)] were exposed to temperatures of 28°, 34°, and 40°C for 6 hr daily for 90 days. Root zone temperature did not affect dry weight of shoots or roots of ixora or citrus, but the 40° treatment increased the shoot to root ratio, S:R. Banana shoot dry weight decreased linearly with increasing root zone temperature, but root dry weight was not affected. The 40° root temperature regime reduced root dry weight in dracaena but not shoot dry weight. Absolute concentrations of sugars and starch in shoots and roots of the 4 test plants did not differ with root temperature, but the ratio of sugars to starch in roots was reduced in ixora and increased in banana by the 40° treatment.
A solid-state, electronic controller was designed and built to maintain de“sired root-zone temperatures in specially designed root heating tubes. The controller uses a thermistor feedback mechanism to an operational amplifier circuit. The tubes were constructed from 7.5-cm-diameter metal pipe, electrical heating tape, a rubber coating, and pipe insulation. Each controller can maintain treatment temperatures in 16 tubes; four tubes at each of four temperatures. Temperatures can be maintained from ambient to 50C with a precision at 35 of ± 0.9C within and between tubes.
Short-term effects of root-zone temperatures (RZT) of 28, 33, 38, and 43C for 6 hours daily on container-grown Musa spp. (AAA) `Grande Naine' and Ixora chinensis L. `Maui' were determined under greenhouse and growth room conditions. Diurnal fluctuation of leaf carbon assimilation (LCA) was altered by treatments. In the growth room at 43C, the maximum LCA occurred about midday for banana, but not until afternoon in ixora. LCA was highest (0.53 mg CO2/m2 per sec) in banana with a 33C RZT under greenhouse conditions, while it was equally high (0.74 mg CO2/m2 per sec) at 33 and 38C in a growth room. In ixora, 33C induced the highest LCA (0.40 mg CO2/m2 per sec) in the greenhouse at 1200 hr, but there were no apparent differences in midday LCA between plants with RZT of 28, 33, and 38C in the growth room. Effects of RZT and environment on the daily fluctuations of gaseous exchange processes raise questions about using measurements at only one time during the day to separate treatment effects.