Growth and allocation strategies of some perennial weeds of slash and burn agriculture (Jhum) in northeastern India

1983 ◽  
Vol 61 (4) ◽  
pp. 1300-1306 ◽  
Author(s):  
K. G. Saxena ◽  
P. S. Ramakrishnan
Keyword(s):  
Dry Matter ◽  
Leaf Tissue ◽  
Imperata Cylindrica ◽  
Total Biomass ◽  
Perennial Weeds ◽  
Matter Production ◽  
Allocation Patterns ◽  
Net Assimilation ◽  
Phosphorus And Potassium ◽  
Growth And Allocation

Growth and allocation patterns of dry matter and nutrients (nitrogen, phosphorus, and potassium) in four important perennial weeds, viz., Eupatorium odoratum, Grewia elastica, Imperata cylindrica, and Thysanolaena maxima, were analysed. Eupatorium odoratum, a C3 species and exclusively dependent upon the sexual mode of reproduction, had the highest values for relative growth rate and net assimilation rate. This species also showed the highest concentrations of nutrients in the leaf tissue. Eupatorium odoratum exhibited a greater allocation of its total biomass as well as nutrients to stem as compared with the other three species all of which can "sprout" (regenerate from underground organs) after fire. The reverse was true for the allocation of biomass and nutrients to the leaf component. The two rhizomatous species (I. cylindrica and T. maxima) diverted significantly greater proportions of dry matter as well as nutrients to belowground tissues compared with the two nonrhizomatous species (E. odoratum and G. elastica). The two C4 species, I. cylindrica and T. maxima, showed higher efficiency in nutrient uptake in spite of their low nutrient demand per unit dry matter production. The findings are discussed in relation to the photosynthetic and regenerative strategies of these species.

Effects of Temperature and CO2Concentration on the Growth of Cotton (Gossypium hirsutum), Spurred Anoda (Anoda cristata), and Velvetleaf (Abutilon theophrasti)

Weed Science ◽  
1988 ◽  
Vol 36 (6) ◽  
pp. 751-757 ◽  
Author(s):  
David T. Patterson ◽  
Maxine T. Highsmith ◽  
Elizabeth P. Flint
Keyword(s):  
Dry Matter ◽  
Dry Weight ◽  
Net Assimilation Rate ◽  
Assimilation Rate ◽  
Short Term ◽  
Leaf Weight ◽  
Matter Production ◽  
Total Plant ◽  
Net Assimilation ◽  
Total Dry Weight

Cotton, spurred anoda, and velvetleaf were grown in controlled-environment chambers at day/night temperatures of 32/23 or 26/17 C and CO2concentrations of 350 or 700 ppm. After 5 weeks, CO2enrichment to 700 ppm increased dry matter accumulation by 38, 26, and 29% in cotton, spurred anoda, and velvetleaf, respectively, at 26/17 C and by 61, 41, and 29% at 32/23 C. Increases in leaf weight accounted for over 80% of the increase in total plant weight in cotton and spurred anoda in both temperature regimes. Leaf area was not increased by CO2enrichment. The observed increases in dry matter production with CO2enrichment were caused by increased net assimilation rate. In a second experiment, plants were grown at 350 ppm CO2and 29/23 C day/night for 17 days before exposure to 700 ppm CO2at 26/17 C for 1 week. Short-term exposure to high CO2significantly increased net assimilation rate, dry matter production, total dry weight, leaf dry weight, and specific leaf weight in comparison with plants maintained at 350 ppm CO2at 26/17 C. Increases in leaf weight in response to short-term CO2enrichment accounted for 100, 87, and 68% of the observed increase in total plant dry weight of cotton, spurred anoda, and velvetleaf, respectively. Comparisons among the species showed that CO2enrichment decreased the weed/crop ratio for total dry weight, possibly indicating a potential competitive advantage for cotton under elevated CO2, even at suboptimum temperatures.

Comparative Water Relations, Photosynthesis, and Growth of Soybean (Glycine max) and Seven Associated Weeds

Weed Science ◽  
1983 ◽  
Vol 31 (3) ◽  
pp. 318-323 ◽  
Author(s):  
David T. Patterson ◽  
Elizabeth P. Flint
Keyword(s):  
Glycine Max ◽  
Water Relations ◽  
Dry Matter ◽  
Stomatal Closure ◽  
Growth Dynamics ◽  
Dry Matter Production ◽  
Matter Production ◽  
Net Assimilation ◽  
Prickly Sida ◽  
Smooth Pigweed

Growth dynamics, water relations, and photosynthesis of soybean [Glycine max(L.) Merr. ‘Ransom’], common cocklebur (Xanthium pensylvanicumWallr.), jimsonweed (Datura stramoniumL.), prickly sida (Sida spinosaL.), sicklepod (Cassia obtusifoliaL.), smooth pigweed (Amaranthus hybridusL.), spurred anoda [Anoda cristata(L.) Schlect.], and velvetleaf (Abutilon theophrastiMedic.) were compared in a controlled-environment greenhouse programmed for 32C day and 23C night temperatures. Net photosynthetic rates, net assimilation rates, and water-use efficiency on a whole-plant or single-leaf basis were greatest in the C4-plant, smooth pigweed. Total dry-matter production at 29 days after planting was greatest in common cocklebur and least in jimsonweed. Interspecific differences in dry-matter production were highly positively correlated with leaf area duration and negatively correlated with net assimilation rate. Threshold leaf water-potential levels causing stomatal closure varied among species. The stomata of jimsonweed were the most sensitive to water stress and those of prickly sida were the least sensitive.

The Potential Allelopathic Characteristics of Bitter Sneezeweed (Helenium amarum)

Weed Science ◽  
1989 ◽  
Vol 37 (5) ◽  
pp. 665-669 ◽  
Author(s):  
Albert E. Smith
Keyword(s):  
Liquid Phase ◽  
Seedling Growth ◽  
Dry Matter ◽  
Solid Phase ◽  
Leaf Tissue ◽  
Italian Ryegrass ◽  
Aqueous Extracts ◽  
Leaf Extracts ◽  
Root Extracts ◽  
Matter Production

Research was conducted to determine the potential for allelopathy to occur in pastures infested with bitter sneezeweed. Aqueous extracts of bitter sneezeweed leaves reduced alfalfa and Italian ryegrass seedling growth as much as 50% at concentrations of 0.5% (w/v). Leaf extracts were more phytotoxic than either stem or root extracts and seedling growth was reduced more than seed germination. Bitter sneezeweed tissue mixed in potting soil at concentrations as low as 0.3% w/w reduced alfalfa seedling numbers by 43%, plant height by 26%, and foliage dry matter production by 54% compared to plants cultured in soil without bitter sneezeweed leaf tissue. The potential concentration of bitter sneezeweed leaf material in soil in the pasture ecosystem was determined to be 0.5% w/v in the liquid phase and 0.2% w/w in the solid phase. Alfalfa seedling growth was reduced by 70% when germinating seed were placed under a bell jar with a potted mature bitter sneezeweed plant compared to control seedlings. A potential exists for bitter sneezeweed interference with developing alfalfa and Italian ryegrass seedlings following fall interseeding into pastures infested with bitter sneezeweed.

AN ANALYSIS OF DRY MATTER PRODUCTION OF DOUGLAS-FIR SEEDLINGS IN RELATION TO TEMPERATURE AND LIGHT INTENSITY

1967 ◽  
Vol 45 (11) ◽  
pp. 2063-2072 ◽  
Author(s):  
Holger Brix
Keyword(s):  
Light Intensity ◽  
Leaf Area ◽  
Dry Matter ◽  
Douglas Fir ◽  
Dry Matter Production ◽  
Dry Matter Distribution ◽  
Pronounced Increase ◽  
Light Intensities ◽  
Matter Production ◽  
Net Assimilation

Seedlings of Douglas fir (Pseudotsuga menziesii (Mirb.) Franco) were grown in growth chambers under all combinations of three temperatures (13, 18, and 24 °C) and three light intensities (450, 1000, and 1800 ft-c). Dry matter production of leaves, stem, and roots was determined at 65 and 100 days after germination. The leaf area produced per unit of leaf dry weight and the dry matter distribution to the plant organs was measured. Net assimilation rates between the ages of 65 and 100 days were calculated. Rates of photosynthesis per unit of leaf were determined at different light intensities and temperatures, and rates of respiration of plant top and of roots were found for different temperatures.Increasing light intensity affected dry matter production in two opposing ways: (i) it increased the rate of photosynthesis per unit leaf area, and (ii) it decreased the leaf area added per unit of dry matter produced. A pronounced increase in growth with increase in temperature from 13 to 18 °C was a result of a temperature influence on production of leaf area rather than the effect of photosynthesis per unit of leaf. Net assimilation rates decreased with increase in temperature at all light intensities.

A quantitative study of the effects of gibberellic acid on the growth of Festuca arundinacea

1968 ◽  
Vol 19 (2) ◽  
pp. 221 ◽  
Author(s):  
DG Morgan
Keyword(s):  
Gibberellic Acid ◽  
Festuca Arundinacea ◽  
Dry Matter ◽  
Growth Analysis ◽  
Shoot Growth ◽  
Plant Weight ◽  
Matter Production ◽  
Whole Plant ◽  
Total Plant ◽  
Net Assimilation

Single plants of Festuca arundinacea (cv. S170) were treated with gibberellic acid (GA) and the sequence of effects on the growth of the whole plant and of various organs followed by means of growth analysis. The first effect of GA was to change the distribution of dry matter between shoot and root and between tillers within the shoot without affecting total plant weight. Shoot growth was increased and resulted in a larger amount of photosynthetic tissue with a higher net assimilation rate; total plant weight increased as a consequence of these effects. The significance of these results in interpreting previous work on the effects of GA on dry matter production in grasses and other plants is discussed.

Relationships between production, nutrient accumulation, and chlorophyll synthesis in an Eleocharis quadrangulata population

1971 ◽  
Vol 49 (6) ◽  
pp. 883-888 ◽  
Author(s):  
Claude E. Boyd ◽  
David H. Vickers
Keyword(s):  
Standing Crop ◽  
Dry Matter ◽  
Aquatic Macrophytes ◽  
Chlorophyll Synthesis ◽  
Early Spring ◽  
Chemical Substances ◽  
Net Productivity ◽  
Matter Production ◽  
Phosphorus And Potassium ◽  
Nitrogen Phosphorus

Maximum standing crop in an Eleocharis quadrangulata population was estimated at 881 g dry wt./m2. Net daily productivity was highest during May when about 50% of the total standing crop was produced. Net productivity for the entire period of vegetative increase, April 1 to August 4, was 7.0 g/m2 per day. The accumulation of several nutrients, especially nitrogen, phosphorus, and potassium was proportionately more rapid than dry matter production during early spring growth. Net chlorophyll synthesis was also greater during early spring. Patterns of change in dry matter and chemical substances in the E. quadrangulata population were similar to those in populations of other emergent aquatic macrophytes.

Effects of Nitrogen, Phosphorus, Potassium and Magnesium on Growth of the Oil Palm

1972 ◽  
Vol 8 (4) ◽  
pp. 347-353 ◽  
Author(s):  
R. H. V. Corley ◽  
C. K. Mok
Keyword(s):  
Leaf Area ◽  
Oil Palm ◽  
Dry Matter ◽  
Fertilizer Application ◽  
Dry Matter Production ◽  
Matter Production ◽  
Oil Palms ◽  
Net Assimilation ◽  
Nitrogen Phosphorus ◽  
Bunch Yield

SUMMARYPotassium application appeared to increase dry matter production and yield of oil palms, primarily by increasing leaf area, while nitrogen increased both leaf area and net assimilation rate. Responses to phosphorus and magnesium were harder to interpret. Production of vegetative dry matter attained a fairly constant level at the higher rates of fertilizer application, while the ratio of bunch yield to total dry matter production was little affected by fertilizer treatments. The importance of these results for oil palm breeding, and their possible value in diagnosing fertilizer requirements, are briefly discussed.

scholarly journals WATER RELATION, GAS EXCHANGE AND DRY MATTER PRODUCTION OF COCONUT (COCOS NUCIFERA, L.) UNDER UNIRRIGATED AND IRRIGATED CONDITIONS

CORD ◽  
1997 ◽  
Vol 13 (02) ◽  
pp. 34
Author(s):  
K.V. Kasturi Bai ◽  
V. Rajagopal ◽  
D. Balasimha ◽  
P. Gopalasudaram
Keyword(s):  
Gas Exchange ◽  
Dry Matter ◽  
Cocos Nucifera ◽  
Irrigation Treatment ◽  
Water Relation ◽  
Beneficial Effects ◽  
Matter Production ◽  
Net Assimilation ◽  
Cocos Nucifera L ◽  
Better Than

The response of local West Coast Tall (WCT) and the two hybrids viz., WCT x Chowghat Orange dwarf (COD) and COD x WCT to moisture availability in terms of water relation, gas exchange and dry matter (DM) production was studied. Discernible differences were noticed between the irrigation treatment (viz., irrigated vs unirrigated) with lower stomatal conductance and transpiration rate in the palms with out irrigation. Irrespective of the cultivar of hybrid leaf water potential was also significantly higher in irrigated palms. Net assimilation rate was lower under uniriigated condition. However genotypic or treatment differences were not significant. Annual DM production also vaned markedly between the irrigation treatments. Treatment differences were significant on the reproductive (RDM) rather then vegetative DM (VDM) production. Under the irrigation treatment the hybrids performed better than the local tall However the percentage reduction in the DM production was relatively less in the local WCT cultivar under unirrigated as compared with irrigated condition. The studies clearly highlighted the beneficial effects of irrigation on DM production and yield in coconut and the adaptability of the local WCT variety under limited water supply than the two hybrids.

scholarly journals Impact of Reduced Rainfall on Above Ground Dry Matter Production of Semi-natural Grassland in South Gloucestershire, UK: A Rainfall Manipulation Study

2021 ◽  
Vol 9 ◽  
Author(s):  
S. M. Ayling ◽  
Jill Thompson ◽  
A. Gray ◽  
L. J. McEwen
Keyword(s):  
United Kingdom ◽  
Dry Matter ◽  
Dry Matter Production ◽  
Drought Risk ◽  
Total Biomass ◽  
The South ◽  
The United Kingdom ◽  
South West ◽  
Matter Production ◽  
Rainfall Reduction

In the United Kingdom, agricultural grasslands cover 40% of the land area, make up 89% of the total agricultural area and are an important land use for ecosystem services and food security. Climate change predictions suggest that the United Kingdom will experience more frequent and severe periods of drought that may impact these grasslands. As part of the Drought Risk and You (DRY) project, a field experiment in which rain shelters reduced precipitation reaching the vegetation by approximately 50%, was set up in the South West of England. The experiment ran for 3 years, from October 2015 to October 2018. The study was carried out at two locations in the catchment of the Bristol River Frome. Both sites were species-rich semi-natural pastures that had received no inputs of fertilizer or herbicide for many years. Automatic weather stations recorded environmental conditions, especially rainfall, within the experimental area. The existing agricultural management regimes were approximated by cutting the vegetation in the plots, by hand, at the appropriate times of year. The effect of rainfall reduction on plant growth was assessed by biomass sampling. At both sites, the rainfall reduction treatment had only small effects on total above ground dry matter production (biomass). These effects were much smaller than the year-to-year variation in total biomass. Our results suggested that well-established permanent pastures in the South West of England were able to tolerate a 3-year period of reduced water supply. The observed year-to-year variation in biomass demonstrated how important the timing of dry weather is for biomass production, and this will be reflected in effects on yield and quality of hay.

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