Nayana N. Barthakur

Nutritive value of the chebulic myrobalan (Terminalia chebula Retz.) and its potential as a food source.

Abstract The edible fruit tissue of the chebulic myrobalan ( Terminalia chebula Retz.) was analyzed for certain organic and mineral nutrients. Compared with commercial apples the tissue contained 10·3 and 14·5 times more vitamin C and protein, respectively. Of the 14 macro- and micro-nutrients studied, the minimum Recommended Dietary Allowance (RDA) for Se, K, Mn, Fe and Cu can be met (100, 63·5, 32, 30 and 28·5%, respectively) if 100 g of the raw fruit is eaten. Aspartic acid, glutamic acid, arginine, proline and lysine constituted 39·6, 8·6, 6·7, 6·4 and 5·0%, respectively, of the total amino acids. These results demonstrate that the chebulic myrobalan is highly nutritious and could be an important source of dietary supplement in vitamin C, energy, protein and mineral nutrients.

A comparative study of radiometric and electronic leaf wetness sensors

Abstract The performances of a beta-ray gauge system (A) and an electronic sensor (B) as surface wetness detectors were compared under laboratory and field conditions. Sensor A indicated longer surface wetness duration time than sensor B under identical environmental conditions. Detection limit of sensor A was lower than sensor B. Leaf surface wetness duration due to natural precipitation was measured more realistically by sensor A than sensor B. This was attributed to the utilization of a real leaf for sensor A and a physical model for sensor B as condensing surfaces.

The effect of boron on calcium uptake and growth in micropropagated potato plantlets.

SummaryBoron (B) requirements differ widely among plant species and the concentration range between toxicity and deficiency is less for B than for any other nutrient. Excess B can adversely affect calcium (Ca) uptake and plant growth. Potato cvs Bintje and Norland plantlets were micropropagated on Murashige & Skoog (MS) nutrient medium, supplemented with 3 (MS control level) or 9 mM Ca, and a range of H3BO3 levels (0.025 to 0.300 mM B). Medium B levels of 0.100 and 0.300 mM decreased Ca content in leaves and shoots of cv. Norland, but not Bintje. Medium B level of 0.025 mM, which is 25% of the control MS level, enhanced Ca uptake in cv. Norland and did not compromise normal plantlet growth in either cultivar. This lower H3BO3 level (0.025 mM B), and a B-free gelling agent such as Gelrite, could be used for micropropagation of potato and possibly other species susceptible to Ca defifiency disorders.

The Indian laburnum (Cassia fistula L.) fruit: an analysis of its chemical constituents

The edible fruit tissue of Indian laburnum fruit (Cassia fistula L.), a member of the leguminosae family, was analyzed for certain organic compounds and mineral nutrients. Of the nine macro- and micronutrients studied, K was the most highly concentrated such that 100% of the US Recommended Dietary Allowances (RDA) for adults could be met by the consumption of about 100 g of the fresh fruit. Na contents in pulp and seeds are relatively low. Ca content at 827 mg per 100 g of dry matter is one of the highest of any fruits, and could contribute towards the RDA requirement of 800 mg of Ca for adults per day. The fruit is a good source of Fe and Mn, and their concentrations are considerably higher than those found in apple, apricot, peach, pear, and orange. Aspartic acid, glutamic acid, and lysine constituted 15.3, 13.0, and 7.8% of the total amino acids respectively in the pulp. In the seeds the same amino acids constituted, 16.6, 19.5, and 6.6%. The relatively high energy content of the fruit at 18 kJ/g could enhance the daily energy requirement of people in need of adequate caloric intake. The results of the present study demonstrate that the Indian laburnum fruit could be a source of some important nutrients and energy for humans.

A study of the effect of growth regulators and time of plantlet harvest on the in vitro multiplication rate of hardy and hybrid tea roses

The effect of benzyladenine (BA) (0, 0.5, 2.5, 5 and 10 ppm), naphthaleneacetic acid (NAA) (0,0.005,0.01,0.1 and 1 ppm) and time of proliferation (six, eight and ten weeks) on the optimum multiplication conditions for four Rosa hybrida cvs Champlain, John Franklin, John Paul II and Landora were studied. BA and NAA both had a significant effect on the proportion of viable plantlets and on multiplication rates while low or high concentrations of these growth regulators in the medium generally caused a reduction of plant material. The optimum multiplication rate also varied with cultivar and time. Concentrations of NAA above 0.1 ppm decreased the multiplication rate significantly for two of the cultivars. There was no consistent response between multiplication rates and cultivars to concentrations of B A, NAA or even the time of culture, and it is therefore recommended that each of these variates be determined for each cultivar to obtain optimum plantlet yield.

The β-ray gauge as a leaf surface wetness detector

Abstract Surface wetness duration was measured by a β-ray gauge as a function of wind velocity in the laboratory. Determination of mass transfer obtained from these results agreed well with a standard theoretical relationship for laminar flow over a flat plate. The β-ray gauge was field tested as a dewmeter over a wax bean canopy.

Water use efficiency and total dry matter production of bush bean under plastic covers

Copyright (c) 1997 Elsevier Science B.V. All rights reserved. Bush bean plants were used to study water use efficiency (WUE) and total dry matter (TDM) production for well-watered, moderately watered, and water-stressed plants grown in the open, and inside covers of perforated and non-perforated plastics. WUE increased quadratically (0.83≤R 2 ≤0.98) with days after plant emergence to harvest for the three soil moisture regimes under each covering treatment. The water-stressed plants in the open and under the closed plastic attained the maximum and the minimum WUE, respectively. TDM increased quadratically with time following plant emergence (0.88≤R 2 ≤0.99). The water-stressed plants had the minimum TDM at the time of pod formation (55 days). These results were attributed to the modified microclimates inside the perforated and closed plastic covers compared with the open. Stomatal conductance was lowest inside the closed plastic and highest in the perforated enclosure, with intermediate values in the open. The temperature difference between leaf and ambient air was significantly higher for the open compared with the covered treatments. The leaf-to-air vapour pressure deficit was lowest for well-watered plants under closed cover and highest for those in the open. Well-watered and moderately stressed bush bean produced the highest TDM inside perforated plastic covers during the pod formation stage. This suggests that perforated plastic covers might be used to enhance bush bean production in semi-arid regions.

Airborne metal pollutants in high elevation forests of southern Quebec, Canada, and their likely source regions

Abstract Atmospheric metal pollution in high elevation forests of southern Quebec was investigated through analysis of airborne particulates, calculation of elemental enrichment factors, and air mass back-trajectory analysis. Metal concentrations (ng m −3 ) of Al, As, Cu, Fe, La, Mg, Mn, Na, Sb, V, and Zn in airborne particulates varied significantly throughout 1993. The Mn concentration at Roundtop Mountain in southern Quebec was generally higher than the reported concentration from the Champlain Valley in the northeastern USA. Concentrations of Mn and those of Al, La, V, and Zn were significantly ( P ≤ 0.05) correlated. Except for the probably local soil-dust origin of Fe and La, enrichment factors suggested that the metal composition of airborne particulates could be attributed to their long-range transport through the atmosphere. The wind direction frequency measured at the research site in a mountain forest was not suitable for identification of likely source regions for metal pollutants. However, air mass back-trajectories indicated that air parcels that moved over Canadian and US industrialized and metropolitan areas may contribute to Mn pollution in rural high elevation regions. This study supports the contention that the atmospheric input of toxic trace metals should be a matter of concern in high elevation forests.

Chemical composition and proposed use of two semi-wild tropical fruits

Abstract The edible fruits of two native species of Southeast Asia, Baccaurea sapida (Roxb.) Muell. Arg. and Flacourtia jangomas ( Lour.) Raeusch, were analyzed for sugars, amino acids and minerals. The values obtained (B. sapida and F. jangomas, based on dry weight) are: protein 5·5, 3·9%; vitamin C 178, 218 mg/100 g; fructose, α- and β-glucose and sucrose 21%, 21% total; Ca 169, 175; K 137, 158; P177, 147; Fe 100, 118; Mg 105, 57 mg/100 g. Concentrations of amino acids, Na, Mn, Cu and Zn are also reported. These fruits would be useful as supplements to a balanced diet.

Salinity stress and sodium-potassium interactions in micropropagated potatoes

SummaryIncreased potassium (K) fertilization of saline soils has been implicated in alleviating salt stress in plants. We examined whether varying K concentrations in Murashige & Skoog (MS: 1962) basal medium could affect salt (NaCl) stress in micropropagated potatoes. Plantlets of cvs Sierra and Russet Burbank were evaluated after 1 month of growth in a medium containing 0. 40, or 80 mM NaCl and 6,20, or 30 mMK. The medium K was adjusted using KNO3 while total nitrogen was kept constant using NH4NO3. Growth parameters were less affected in Sierra than Russet Burbank, and roots were less affected than shoots, as the medium salinity increased. Tissue Na levels were greater when the medium K was 6 mM compared with 20 mM MS control. The medium K concentration 50% greater than MS control did not promote growth and did not limit tissue Na levels. While this should be confirmed by field assessment, our results suggest that while K deficiency promotes salt damage, its addition beyond the usual fertilizer recommendations is not beneficial in alleviating salinity stress.