Dry Weight Data Research Articles

Studies of grain production in Sorghum vulgare. I. The contribution of pre-flowering photosynthesis to grain yield

Sorghum plants were allowed to assimilate known relative amounts of 14C in the two periods: (i) from full expansion of the third uppermost leaf to anthesis; and (ii) from anthesis to grain maturity. By comparing relative 14C activity in the mature grain, the relative partitioning of photosynthate between grain production and other uses in the two periods was calculated. Plant and grain dry weight data from another experiment showed the amounts of net photosynthesis in the two periods. It was then possible to calculate the maximum amount of the material assimilated in the pre-anthesis period that could have gone to grain production, and thus the percentage of grain material derived from this earlier period. The estimate was 12%.

Analysis of genetic variations in plant type of rice

To examine genetic variation in the growth curve parameters and their contribution to factors determining grain yield, 40 randomly chosen F 7 lines of a cross between two contrasting rice varieties were measured for dry matter weight and for other yielding characters during the growing period. From the dry weight data, growth curves were computed using linear and quadratic (Pearl-Reed) logistic equations, and various values derived from them were compared among lines. The results showed that: 1) The growth curves of the lines varied genetically between the "early-vigor" and "sustained-vigor" types. 2) Total panicle length per unit area, representing the potentiality for carbohydrates to be produced in grains, seemed to depend on the growth rate at floral initiation, and panicle weight per unit length, representing the rate of carbohydrate supply to the panicles, seemed to depend on the growth rate at heading. These two values were negatively correlated. 3) "Early-vigor" types tended to produce more panicles but had a low rate of carbohydrate supply than "sustained-vigor" types. Either "potentiality" or "supply" was a limiting factor in grain production, depending upon the pattern of growth being either "early-vigor" or "sustained-vigor" type.

Leaf Growth and Development in the Young Tobacco Plant

The growth of the vegetative shoot of tobacco, Nicotiana tabacum L., and the associated changes in dry weight of the whole plant and its major parts are described. By means of serial reconstruction, the volume changes of successive young leaf primordia are followed, and this information is integrated with the dry weight data for older leaves.

Intersprout competition in the potato II. Competition for nutrients during pre-emergence growth after planting

The influence of temperature, number of sprouts per tuber and concentration of supplementary inorganic nutrients on sprout growth and intersprout competition for tuber substrates during emergence was investigated in the potato varietyArran Pilot. The rate of sprout growth was found to be a positive function of initial tuber fresh weight. Dry weight data at emergence indicated that individual sprouts on multi-sprout tubers exhibited mutual interference for substrates from the tuber. The intensity of this interference increased with temperature in the range 7 25 C, but interference was reduced, and in some cases eliminated, by supplying inorganic nutrients in the rooting medium. It was concluded that a component of the inorganic nutrient solution used could replace the tuber factor the supply of which limited sprout growth. The effects of temperature and inorganic nutrient concentration on the partitioning of dry matter within the plant are deseribed and diseussed.

Dry Weight, Ash, and Volume Data for Some Freshwater Planktonic Algae

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A comparison of the phosphorus nutrition of Australian heath plants and introduced economic plants

Dry weight and phosphorus fractionation data are presented for seven species grown over a range of phosphorus levels from 0.Wi to 10.0 p.p.m. in 2 iitres of water culture. As the phosphorus level was established at the beginning of the experiment and not afterwards adjusted, the maximum available phosphorus for each species (six plants per pot) was within the range of 0.3 to 3000 μg, plus seed phosphorus, per plant. The species were representative of two groups: species indigenous to the heath formation (Eucalyptus baxteri, Casuarina pusilla, Acacia suaveolens, and Banksia ornata) and introduced economic species now being grown with fertilizer on the same soils (Pinus radiata, Avena sativa, and Trifolium subterraneum). Results showed that at least one of the economic species, T. subterraneum, was able to absorb phosphorus from nutrient solutions to the same extent as the native species. No difference in growth, as measured by total dry weight, was observed in any species in the nutrient cultures containing less than 30 μg P per plant. 300 μg P per plant produced extra growth in all species except P. radiata, which responded only at 3000 μg P per plant. Nutrient imbalance temporarily decreased growth in all cultures containing 3000 μg P per plant. An important factor in the growth of perennial heath species at low levels of substrate phosphorus is considered to be an increase in the percentage of orthophosphate in the plant at a time of the year when active growth is being made. Other factors, such as the low death-rate of leaves and an efficient means of redistribution of nutrients from senescing leaves, may also be important. The significance of these findings in relation to the growth of the indigenous species in the field is discussed. Species which possess all these characteristics have a decided advantage for survival in low phosphorus environments.

STUDIES ON OXALIS PES‐CAPRAE L. IN AUSTRALIA

Summary. The widespread pentaploid variety of the important weed, Oxalis pes‐caprae was harvested eight times throughout its life cycle. Dry weight and oxalate (acid‐soluble and water‐soluble analyses were made on all parts of the plant at each harvest.From the dry weight data obtained, attention is drawn to three stages during the growth of the plant — namely, the stage of old bulb exhaustion, the time when flowers and new bulbs begin to appear and the onset of senescence. Corresponding with these stages marked changes in oxalate metabolism and/or transport are observed.It is proposed that the stage of old bulb exhaustion would be the most promising at which lo attempt control of the weed by cultivation. Recherches sur Oxalis pes‐Caprae L. en Australie. I. Études quantitatives de l'acide oxalique durant le cycle vital de la variété pentaploide

Effetto del Prodotto Brachizzante “AMO-1618” sulla Crescita e sul Contenuto in Alcaloidi diDatura StramoniumL.

Abstract The influence of the growth retarding chemical « AMO-1618 » on the growth and alkaloid content in DATURA STRAMONIUM L. — AMO-1618 (4-hydroxy-5-isopropyl-2-methylphenyl trimethylammonium chloride, 1-piperidine carboxylate) in concentration of 100 and 500 p.p.m. was applied as an aqueous spray, every day for a fortnight period, to the leaves and tops of Datura stramonium L. The treated plants showed a reduction in growth only at the beginning, they looked, however, expecially the ones receiving the treatment with the highest concentration of the compound, more compact, sturdier and with leaves darker green and more thickened than the control. The plants were harvested four weeks following treatment. Fresh and dry weight data of leaves and roots indicated no significant change in stramonium plants treated with 100 p.p.m., while the ones treated with 500 p.p.m. showed an appreciable increase in leaves weights accompanied by a decrease in roots weights. No significant difference, between treated and u...

Plankton from the East African Area of the Indian Ocean

AN earlier communication1 has described how a series of plankton samples was taken from the coastal strips of Kenya and Tanganyika, extending outwards for some 50 miles. An analysis of some of the dry-weight data shows the following results.

The Influence of Gibberellic Acid on the Growth andAlkaloid Biogenesis in Datzura stramonium Linné and in Atropa belladonna Linné

Gibberellic acid in concentrations of 100 and 1,000 p. p. m. was administered as an aqueous spray to the leaves and tops of Datura stramonium and Atropa belladonna . Characteristic effects on the growth of the treated plants are described. Significant increases in plant height were demonstrated. The fifty-four-day-old stramonium plants were harvested four weeks after the first treatment. Fresh and dry weight data indicated increases in total, leaves and tops, and stem weights, but decreased root weight. The twelve-week-old belladonna plants were harvested seven weeks following treatment. Appreciable decreases in leaves and tops and root dry weights were noted. However, this was accompanied by significant increases in stem weight. Stramonium plants receiving both a single and double spray treatment with each concentration of gibberellic acid showed decreases in the concentration of total alkaloids in the leaves and tops and in the stems. Increased alkaloid roduction was observed in the roots. The favorable effects on growth from the two-spray treatment of 100 p. p. m. of gibberellic acid resulted in significant increases in total alkaloid production. Significant decreases in the concentration of alkaloids in the plant organs of belladonna were noted. Further, the total alkaloid content of belladonna treated with gibberellic acid was about one-half that of the untreated plants.

The problem of assessing strains: A study in grass-breeding technique

1. This paper reports a study of the behaviour of five strains of ryegrass (Devon Eaver, Irish S. 24 and New Zealand certified mother perennial ryegrass and H.I) under three different conditions of spacing and two types of management. Strain performances are compared on the basis of green and dry-weight data of total herbage, and green weight of sown strain contributions under the three techniques of evaluation.2. Under both managements, the total annual production per unit area was greatest from broadcast and least from single-plant areas. Some individual cut yields were, however, greater than those from broadcast plots, with the drill-row production intermediate.3. Yield differences between the four perennial ryegrasses were greatest as spaced plants and least in broadcast plots. Single plants and broadcast plots of H. 1 were outstanding compared with the perennial strains. Under neither management were there significant interactions between strains and sowing method in 1952, though such interactions were detected in both cases during 1953.4. The relative yield performance of strains under similar spacing conditions were almost identical under both managements.

Interaction of 16 epi-estriol and estradiol 17 beta on uterine growth.

SummaryThe adult, ovariectomized rat was used to ascertain the effects of a new estrogen, 16 epi-estriol, on the activity of estradiol 17β. These results indicate that when 3 daily doses of 5 to 25 νg of 16 epi-estriol are subcutaneously injected into rats receiving 0.1 νg estradiol 17β daily for the 3-day period, the response of the uterus to estradiol is restricted. Normally, 3 daily doses of 0.1 νg estradiol 17β increase the uterine wet weight from the value of the ovariectomized rat from approximately 116 mg to 227 mg. The simultaneous administration of 5, 10, or 25 νg of 16 epi-estriol in addition to the estradiol treatment reduces the response to 191 down to 173 mg. The inhibitory action is likewise reflected in the dry weight data. No apparent modification of the vaginal cornifying action of estradiol could be induced by 16 epi-estriol.

The Response of the Young Tomato Plant to A Brief Period of Water Shortage

The dry weight and water contents data are considered for the individual laminae and petioles of the first eight leaves of tomatoes subjected to a brief period of wilting after they had developed eight easily manipulable leaves. The aim was to obtain a better understanding of the response previously described for the whole plant, by studying the growth of organs which were at various stages of development when treatments were imposed.

INFLUENCE OF PHOSPHORUS SUPPLY AND THE FORM OF AVAILABLE NITROGEN ON THE ABSORPTION AND THE DISTRIBUTION OF PHOSPHORUS BY THE TOMATO PLANT

In the course of studies on the role of phosphorus in the synthesis of proteins by the tomato plant it was noticed that the form in which nitrogen was supplied to the plants had a distinct effect on the development of deficiency symptoms due to lack of phosphorus. A similar experiment has been Teported by Skok (9), who found that the appearance of calcium deficiency symptoms in the bean plant was noticeably delayed in plants that received urea as a source of nitrogen as compared with those that received nitrate nitrogen. He interpreted these results to be in support of Eckerson's findings (7) that calcium is essential for the assimilation of nitrates, by being necessary for the successful catalysis of the reduction of nitrates to nitrites T)y the so-called reducase enzyme. His plants receiving urea were thus supplied with a reduced form of nitrogen and the necessity for nitrate reduction was eliminated. Skok based his conclusions entirely upon fresh and dry weight data and appearance of the plants. He suggested that since other elements (potassium, phosphorus, and sulphur) were also found to be necessary for normal reducase activity by Eckerson (7), their deficiency symptoms may also be lessened in severity by the use of urea. Preliminary experiments in this laboratory indicated clearly that tomato plants utilizing urea as a source of nitrogen, when deprived of their normal supply of phosphorus, did not exhibit the usual signs of phosphorus deficiency as soon as did deficient plants growing in a medium containing nitrate nitrogen. The question arose as to whether this was due to non-utilization of nitrates by the plants receiving nitrate nitrogen, as suggested by Eckerson, or to some other cause. Several experiments in which the plant tissue was dried and analyzed for phosphorus showed clearly that the plants utilizing urea contained much more phosphorus per unit of dry weight than did the plants receiving nitrate nitrogen. Furthermore, during phosphorus starvation it took the plants growing in a medium containing urea longer to deplete this reserve store of phosphorus. It thus became evident that the delay in the appearance of deficiency symptoms by the plants furnished urea might be due to a greater accumulation of phosphorus and not to the removal of the necessity for nitrate reduction by the substitution of urea for nitrate in the nutrient solution.

Chemical Studies in the Physiology of Apples

IN the the nature investigation of the chemical now being processes carried leading on at to the the Imperial break-down College of the of t e nature of the chemical pr esses lea ing o the br k-dow f the apple during storage (4, 5), a rapid method of finding the dry weight of a large number of samples was required. The dry material of tissue of this kind consists of 80-90 per cent, water-soluble substances, chiefly sugars and acids, and 10-20 per cent, cellulose, pectin, and other insoluble substances. Dryweight data should afford a simple means of comparing the amounts of material present in different samples and of tracing losses due to respiration. Also by determining the amount of cell-wall material as well as total dry weight, some measure of changes in the concentration of the sap of the apple can be made.