Search Results
Abstract
A simple dilution technique is described for the calibration of infrared gas analysers for use with carbon dioxide. The technique involves determining the exact volume of a closed loop system, which includes analyser, circulating pump and connecting tubing. Successive dilutions with either known volumes of nitrogen gas with no carbon dioxide or span gas with known concentrations of carbon dioxide, provide a range of calculable concentration points from which the calibration curve can be plotted.
Abstract
Developmental anatomy of interlocular cavitation (IC), defined as the formation of cavities in soft parenchymatous endocarp cells between seed locules, was studied in pods of several snap bean cultivars grown under various cultural and environmental conditions during the years 1969–1972. IC occurred in pods from the stages of rapid pod elongation (6–10 days after anthesis) until the time of pod senescence. Unbalanced swelling of endocarp tissues combined with decreased periclinal cell division and rapid cell elongation are concluded to be the causes of IC. In the most commonly observed form, IC also includes the separation of fused endodermal cells. Pod malformation is greater in pods with severe IC and such pods exhibited more quality defects after processing. Sequential development of this developmental and physiological disorder is illustrated.
Abstract
The propagation method and vegetative condition of ‘Northblue’ blueberry (Vaccinium corymbosum L.) stock plants influenced microshoot production in vitro and root formation on leaf-bud cuttings. In tissue culture (TC), explants from TC-derived stock plants produced longer shoots than explants from leaf-bud, standard- (ST-) derived stock on either Zimmerman’s (Zimm) medium at pH 4.8, Lloyd and McCown’s woody plant medium (WPM) at pH 4.8 or pH 5.2. Microshoots from explants of TC-stock plants also rooted more readily. Microshoot rootability decreased after 18 weeks on medium containing 68.6 μmol (12 mg/liter) 2iP. Microshoot production and rootability increased after 3 additional weeks on Zimm medium without 2iP present. Leaf-bud cuttings of ‘Northblue’ TC-stock plants treated with 5% and 10% concentrations of a commercial rooting compound (Dip-n-Grow) had a slightly higher rooting percentage and root rating than nontreated cuttings from ST-stock plants. However, cuttings from ST-stock plants of the same age showed larger increases in root formation and percentage of rooting in response to the same rooting compound treatments. Leaf-bud cuttings from vegetative TC-stock plants that developed shoots had more basal branches than those from floral ST-stock plants. Branch elongation was greatest and basal branches fewest on cuttings from floral ST stock plants. Successful propagation with cuttings and in vitro explants may be related to the condition of the stock plants, which have been altered by their own propagation methods and the plant growth regulators applied. Chemical names used: 1H-indole-3-acetic acid (IAA); 1H-indole-3-butanoic acid (IBA); 1-naphthaleneacetic acid (NAA); N-(3-methyl-2-butenyl)-2H-purin-6-amine (2iP).
Abstract
Interlocular Cavitation (IC) in snap bean pods was studied in 8 commercial cultivars under several irrigation regimes on a sandy soil. In susceptible cultivars, IC was consistently associated with heavy irrigation during pod growth. Little or no IC was found when no more than 1.27 cm of water was applied per week. Irrigation also influenced pod yield, plant weight, ratio of pod weight to plant weight, pod composition, and seed number. Cultivars susceptible to IC showed rapid increase in pod weight when irrigated after 2-3 weeks of moisture stress conditions. However, this rapid increase in pod weight did not induce IC under the conditions tested. Proportion of pod P and K in relation to Ca and Mg increased as irrigation levels were increased. Seed number was related to irrigation and the severity of IC, depending upon cultivar.
Abstract
‘Northblue’ blueberry (Vaccinium corymbosum L.) plants propagated by tissue culture (TC) have a branching pattern and growth rate different from plants propagated by leaf-bud cuttings. Two to 3 times more basal branches were formed on tissue culture-derived plants by the time they were 27 to 34 weeks old. These basal branches were maintained on older plants in the field, where lateral branching was also twice as high. The growth rate of the young TC-derived plants was 3 times the rate of young leaf-bud, cutting-propagated (ST) plants. However, lateral branch length of older plants in the field was similar for both groups of plants, indicating a reduction in the growth rate of TC-derived plants from 34 to 82 weeks after propagation. Pruning and chilling methods reduced basal branch length and the number of lateral branches produced in the field, while enhancing the length of lateral branches and total buds per lateral branch. Although TC-derived blueberry plants had numbers of total flower buds and total buds per lateral branch similar to ST-derived plants, they produced more flower buds per plant. The enhanced branching framework of TC-derived plants, composed of rapidly forming basal and lateral branches, may increase photosynthesis at an early age and hasten fruit production.
Abstract
Shoot tip cuttings of cucumber (Cucumis sativus L.) taken at various times, ages, and condition were subjected to several pre- and post-selection techniques known to influence rooting in other species. Succinic acid-2,2-dimethylhydrazide (SADH) applied 1 week before shoot tip harvest increased the rooting of cuttings. Neither time of day cuttings were prepared (7 AM or 1 PM) nor fruit load influenced rooting. Sand culture under mist, at 27°C (day), 21° (night), in the greenhouse was superior to other rooting methods tested. Cultivars varied in rooting. Cuttings from early planting rooted better than those from late plantings.
Rosemary (Rosmarinus officinalis) belongs to the Lamiaceae family, and is native to the Mediterranean and one of the most important medicinal herbs containing antioxidants in its leaves. One of the most important antioxidants is rosmarinic acid (RA). The aim of this study was to test the concentration of (RA) and chlorophyll content in leaves and callus of five successive subcultures of five different genotypes of rosemary. They were: 1) `Majorca'; 2) Rosmarinusofficinalis; 3) `Pine Scented'; 4) `Madeline Hill', and 5) APR. It was found that the highest concentration of RA in leaves was in `Pine Scented', while the lowest concentration was for APR and `Madeline Hill'. However, in the callus the highest RA concentration was for Rosmarinusofficinalis in the second subculture and `Madeline Hill' in the third subculture, while the lowest RA concentration was for `Majorca', `Pine Scented', and APR. The RA concentration in callus declined after the second and the third subculture for Rosmarinusofficinalis and `Madeline Hill', respectively. We concluded that it is preferred to use `Pine Scented' for RA extraction from the leaves while for RA extraction from callus it is better to use Rosmarinusofficinalis in the second subculture or `Madeline Hill' in the third subculture.
Rosemary Rosmarinus officinalis is a member of the Lamiaceae. Rosmarinic acid (RA) is a very strong antioxidant produced in the chloroplast, and used to protect plant tissues against oxidative stress. A number of investigations showed that the sucrose concentration in the callus growing medium greatly influenced the production of secondary metabolites of the phenylpropanoid pathway such as RA. The aim of this study was to test the effect of elevated sucrose concentrations (2%, 3%, 4%, 5%, and 6% sucrose) and the effect of light and dark treatments on the production of RA in the callus of five different genotypes. The genotypes were Majorca, Rosmarinus officinalis, Pine Scented, Madeline Hill, and APR. It was found that the dark treatment produces more RA than the light treatment in all genotypes, and in all sucrose concentrations. The RA concentration increased with increasing the sucrose concentration from 2%—reaching the highest concentration at 4% and 5% in most genotypes. The RA concentration declined again at 6% sucrose in all genotypes. We concluded that for the extraction of RA from rosemary callus it is preferred to be produced in the dark—this will save energy and will produce more RA than the light treatment. Also it is preferred to use sucrose concentration at 4% for genotypes Rosmarinus officinalis, Pine Scented, and APR; and 3% sucrose for genotype Madeline Hill in the dark condition. While for the light condition, it is preferred to use 5% sucrose with genotypes Majorca, Rosmarinus officinalis, Pine Scented, and Madeline Hill; and 4% sucrose for genotype APR.
Phenylalanine ammonia-lyase (PAL) enzyme is the most extensively studied enzyme in the phenylpropanoid pathway. Studies on the biosynthesis of rosmarinic acid (RA) showed that the PAL enzyme catalyzes the initial step of the phenylpropanoid pathway. The increase in RA content in plant tissues in vitro coincided with the increase in PAL activity. The aim of this study was to investigate the activity of the gene responsible for the production of the PAL enzyme in the five rosemary genotypes; this will give more understanding about the accumulation of rosmarinic acid in the five rosemary genotypes. The genotypes were Majorca, Rosmarinus officinalis, Pine Scented, Madeline Hill and APR. Northern blot hybridization between the PAL gene primer and the five genotypes' cDNA showed bands at 300 bp in all the five genotypes for the PAL gene. The expression of the PAL gene was high in genotypes Majorca, Rosmarinus officinalis, and Madeline Hill, while the expression was low in genotypes Pine Scented and APR. It was expected that the genotypes having the highest PAL gene expression will produce the highest amount of RA, but the highest genotype in PAL gene expression Madeline Hill had the lowest RA production in their leaves. This could occur due to the tissue specific regulation inside plant tissues. Inside the callus tissues, where the specific tissue regulation no longer exists, the RA was produced in repetitively large amounts in genotypes with high PAL gene expression.
The effects of different cytokinin-like compounds on invertase activities at different tuberization stages of potato (Solanum tuberosum L. `Atlantic') were examined. Single nodal segments were cultured on MS medium plus 6% sucrose and supplemented with either 2 mg kinetin/L, 0.1 mg thidiazuron (TDZ)/L, 1.0 mg AC 243,654/L, 0.1 mg AC 239,604/L, or no cytokinin. Tissue samples for determining invertase activity were taken at three stages of tuberization: stage 1, the “hook stage”; stage 2, the “swelling stage”; and stage 3, “tuber initials.” Invertase activity was significantly affected by the interaction between cytokinin-like compounds and tuberization between cytokinin-like compounds and tuberization stages. The highest invertase activities in the stolons at stage 1 were found in kinetin and TDZ treatments. Invertase activity in the stolons on the control medium significantly increased from stage 1 to 2 and decreased at stage 3. Invertase might play a role in either stolon elongation or carbohydrate utilization by increasing the pool of reducing sugars.