Competition between Chondrilla juncea and Trifolium subterraneum: the influence of canopy areas and heights

1987 ◽  
Vol 38 (2) ◽  
pp. 329 ◽  
Author(s):  
AO Nicholls ◽  
JD Williams ◽  
RM Moore
Keyword(s):  
Trifolium Subterraneum ◽  
Mixed Stands ◽  
Relative Growth ◽  
Competition Analysis ◽  
Relative Growth Rates ◽  
Nitrogen Levels ◽  
Net Assimilation ◽  
Leaf Distribution ◽  
Reproductive Phases ◽  
Chondrilla Juncea

Growth in the field of Chondrilla juncea and Trijolium subterraneum at different nitrogen levels was compared during late vegetative and early reproductive phases in monocultures and mixed stands. Observed differences between the species in terms of relative growth rates and net assimilation rates in monocultures were not reflected in the performance of the species in competitive mixtures. A major factor contributing to this anomaly was the different leaf distribution of the two species in mixtures.The annual T. subterraneum produced a larger area of leaf at a higher level in the canopy than did the perennial C. juncea.The crowding coefficient of C. juncea with respect to T. subterraneum was significantly less than 1, indicating that T. subterraneum was more competitive than C. juncea.Applications of nitrogen at a late stage of growth did not change the competitive ability of the species.Some limitations of the experimental procedure and of the de Wit competition analysis are discussed.

Studies on the sowing dates of cotton in the Sudan Gezira: I. The influence of date of sowing on plant growth and development

1967 ◽  
Vol 69 (3) ◽  
pp. 305-315 ◽  
Author(s):  
J. E. Jackson
Keyword(s):  
Growth Rates ◽  
Slow Growth ◽  
Seasonal Pattern ◽  
Relative Growth ◽  
Relative Growth Rates ◽  
Research Division ◽  
Sowing Dates ◽  
Net Assimilation ◽  
State Growth ◽  
Sudan Gezira

Growth analysis of cotton crops sown in the Sudan Gezira at monthly intervals between August and May revealed a marked seasonal pattern of growth. Irrespective of plant age and fruiting state growth of non-senescent plants was slowest during the cool winter months. Relative growth rates of young plants were highest in August, September and early October due to the high specific leaf areas and fairly high net assimilation rates found then. They were lowest when minimum temperatures were lowest. Net assimilation rates were also lowest in the coolest months, probably as a result of restricted growth. High temperatures in the spring reduced fruiting. It is concluded that low minimum temperatures and high evaporation rates are both associated with slow growth, and play a large part in determining the characteristic decline of growth rates of cotton sown at the usual date in August.I wish to thank the Chief of the Research Division, Ministry of Agriculture, Sudan, for permission to publish this paper and to record my gratitude to the team of field and laboratory assistants, especially Salih Saad and Hassan Osman, who helped in the work.

Studies on the productivity of tropical pasture plants. V.* Effect of shading on growth, photosynthesis and respiration in two grasses and two legumes

1974 ◽  
Vol 25 (3) ◽  
pp. 425 ◽  
Author(s):  
MM Ludlow ◽  
GL Wilson ◽  
MR Heslehurst
Keyword(s):  
Radiant Energy ◽  
Net Assimilation Rate ◽  
Assimilation Rate ◽  
Pasture Production ◽  
Relative Growth ◽  
Relative Growth Rates ◽  
Analysis Techniques ◽  
Net Assimilation ◽  
Photosynthesis And Respiration ◽  
Pasture Plants

Two grasses and two legumes were grown at three illuminances: one grass and one legume in a growth cabinet (100, 50 and 34% relative illuminance) and one of each in a glasshouse (100, 30 and 10% relative illuminance). The response to shading was investigated by using classical growth analysis techniques, and the photosynthesis-respiration balance obtained by Watson and Hayashi's method. Shading caused a reduction in the proportion of root and a corresponding increase in the proportion of leaf, and an increase in the shoot/root ratio in all species except green panic. The relative growth rates of grasses (which were only clearly superior at the highest illuminance) were affected more by shading than were those of legumes, and the greater shading effect resulted from a greater decrease in net assimilation rate, and to a lesser extent, from a smaller compensatory increase in leaf area ratio in the grasses than in the legumes. The greater sensitivity of net assimilation rate of grasses to shading arose from a stronger dependence of the photosynthetic rate on illuminance. The significance of these findings for pasture production is discussed. Both tiller and runner production were dependent upon the total amount of radiant energy received by the plant, and in the growth cabinet, at least, were independent of its intensity, duration and sequence. ______________________ *Part IV, Aust. J. Agric. Res., 25: 415 (1974).

Invasion by Pittosporum undulatum of the Forests of Central Victoria. III. Effects of Temperature and Light on Growth and Drought Resistance

1982 ◽  
Vol 30 (3) ◽  
pp. 347 ◽  
Author(s):  
RM Gleadow ◽  
KS Rowan
Keyword(s):  
Leaf Area ◽  
Photon Flux ◽  
First Year ◽  
Low Light ◽  
Relative Growth ◽  
Relative Growth Rates ◽  
Drought Tolerant ◽  
Deep Shade ◽  
Net Assimilation ◽  
Shade Plants

The clumping of invading seedlings of Pittosporum undulatum Vent. around the butts of established trees is due partly to the site-dependent survival of seedlings. particularly during summer. P. undulatum seedlings were very drought-tolerant when grown at moderately low temperatures (21.4°C day/17.8°C night compared with 27.4°C day/23.9°C night) and in deep shade. Plants droughted at 5°C higher temperatures and higher photon flux densities stopped transpiring and wilted 10-13 days earlier than those droughted under cooler, densely shaded conditions. Well watered seedlings had higher relative growth rates and net assimilation rates when grown under higher temperatures and photon flux densities. Control seedlings were more leafy when grown under low light. as reflected by the specific leaf area, leaf area ratio and root/shoot ratios. The adverse effects of higher photon flux densities and temperatures on the drought tolerance of P. undulatum seedlings support the hypothesis that survlval of invading seedlings in their first year is dependent on the microclimate.

scholarly journals Physical Environment and Symbiotic Nitrogen Fixation II. Root Temperature Effects on the Relative Nitrogen Assimilation Rate

1965 ◽  
Vol 18 (2) ◽  
pp. 295 ◽  
Author(s):  
AH Gibson
Keyword(s):  
Nitrogen Fixation ◽  
Physical Environment ◽  
Temperature Effects ◽  
Nitrogen Assimilation ◽  
Symbiotic Nitrogen Fixation ◽  
Trifolium Subterraneum ◽  
Bacterial Strains ◽  
Root Temperature ◽  
Relative Growth ◽  
Relative Growth Rates

Nitrogen fixation by six varieties of Trifolium subterraneum L., each inoculated with a number of strains of Rhizobium trifolii, was examined over a range of root temperatures. Significant differences in the rate of nodule establishment and early nitrogen fixation were found between varieties, and between bacterial strains. In order to minimize the effect of such differences, relative nitrogen assimilation rates (RN) and relative growth rates (R w) were used to compare the different legume-bacteria associations.

scholarly journals The Carbohydrate Requirements for Symbiotic Nitrogen Fixation: A "Whole-Plant" Growth Analysis Approach

1966 ◽  
Vol 19 (4) ◽  
pp. 499 ◽  
Author(s):  
AH Gibson
Keyword(s):  
Root Nodule ◽  
Symbiotic Nitrogen Fixation ◽  
Relative Rate ◽  
Trifolium Subterraneum ◽  
Plant Size ◽  
Relative Growth ◽  
Relative Growth Rates ◽  
Whole Plant ◽  
And Function ◽  
Nodule Symbiosis

An examination was made of the carbohydrate requirements for the establishment and function of the legume-root nodule symbiosis in Trifolium subterraneum L. The method adopted involved the use of relative growth rates in order to minimize the effect of time and initial differences in plant size. Essential factors in this approach were (i) that the nodulated plants and ammonium nitrate-supplied control plants assimilated nitrogen at the same relative rate, and (ii) that both sets of plants has similar initial photosynthetic capacity.

COMPARISON OF SEEDLING GROWTH OF ROUGH FESCUE AND TALL FESCUE

1969 ◽  
Vol 49 (4) ◽  
pp. 465-470
Author(s):  
D. B. Wilson ◽  
A. Johnston
Keyword(s):  
Tall Fescue ◽  
Growth Rates ◽  
Festuca Arundinacea ◽  
Growth Analysis ◽  
Dry Weight ◽  
Native Grass ◽  
Relative Growth ◽  
Relative Growth Rates ◽  
Net Assimilation ◽  
Rough Fescue

Seedlings of a native grass, rough fescue, Festuca scabrella Torr., and of a tame grass, tall fescue, Festuca arundinacea Schreb., were grown in the greenhouse for 10 weeks. Each week 20 plants of each species were destructively harvested for growth analysis. Leaf and tiller numbers and leaf lengths were recorded for an additional 10 plants of each species. Mean net assimilation rates of rough fescue were similar to those of tall fescue, but leaf area ratios were significantly lower. Thus, mean relative growth rates of rough fescue were less than those of tall fescue. Tiller numbers were similar for both species but rough fescue produced fewer leaves. Dry weight of tops of the tame grass produced during the 10-week period was about 17 times that produced by the native grass.

Aphid-induced changes in growth indices of three leguminous plants: unrestricted infestation

1985 ◽  
Vol 63 (12) ◽  
pp. 2454-2459 ◽  
Author(s):  
C. D. B. Hawkins ◽  
M. J. Aston ◽  
M. I. Whitecross
Keyword(s):  
Acyrthosiphon Pisum ◽  
Growth Patterns ◽  
Relative Growth ◽  
Relative Growth Rates ◽  
Unit Leaf ◽  
Aphis Craccivora Koch ◽  
The Mean ◽  
Net Assimilation ◽  
Induced Changes ◽  
And Control

The effects of various densities of cowpea aphids (Aphis craccivora Koch) and pea aphids (Acyrthosiphon pisum Harris), both Homoptera: Aphididae, on the growth of cowpea (Vigna unguiculata (L.) Walp. cv. Caloona), broad bean (Vicia faba L. cv. Aquadulce), and garden pea (Pisum sativum L. cv. Victory Freezer) seedlings were investigated. Within 10 days of infestation, aphid feeding significantly reduced plant dry weights and mean relative growth rates for the six plant–aphid combinations. In all cases except one, the mean unit leaf or net assimilation rate was also significantly reduced within 10 days. The mean leaf area ratio was the same for infested and control plants. The aphid-induced changes in host plants appear to be due to changes in photosynthesis, respiration, and translocate removal from the phloem over the 10-day period. Changes in the growth patterns of the host plant within this period are similar, but the underlying physiological effects could vary among particular plant–aphid combinations.

The early vegetative growth of three strains of subterranean clover (Trifolium subterraneum L.) in relation to size of seed

1957 ◽  
Vol 8 (1) ◽  
pp. 1 ◽  
Author(s):  
JN Black
Keyword(s):  
Size Distribution ◽  
Agricultural Research ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Dry Weight ◽  
Leaf Production ◽  
Relative Growth ◽  
Relative Growth Rates ◽  
Waite Agricultural Research Institute ◽  
Early Production

Three strains of subterranean clover (Bacchus Marsh, Clare, and Mount Barker) were grown in pot culture at the Waite Agricultural Research Institute; for each strain, seed of four widely separated sizes mere sown. Dry weight a t any one time in the early vegetative stage was linearly related to embryo weight, but was independent of strain. Hence differences in early growth noted under uniform environmental conditions between strains are the result not of differing relative growth rates, but of differences in the size distribution within the seed populations; evidence is presented suggesting that there may well be little difference in the size distribution of seed of Bacchus Marsh and Mt. Barker, but that Clare contains a higher proportion of large seed, and thus as a strain would be expected to give greater early production. Leaf area per plant was also linearly related to embryo weight but independent of strain; but for a common embryo weight, Clare was found to have fewer leaves than the other two strains. Examination of the areas of successive leaves showed that the maintenance of similar total leaf areas depended on a balance of rate of leaf production and size of individual leaves; in relation to Bacchus Marsh and Mt. Barker, Clare has fewer but large1 leaves.

Studies on the nutrition of pasture plants in the South-west of Western Australia. IV The Growth of Subterranueum Clover (Trifolium subterraneum L.) as affected by lime, molybdenum, and Potassium

1952 ◽  
Vol 3 (3) ◽  
pp. 244 ◽  
Author(s):  
RC Rossiter
Keyword(s):  
Growth Rate ◽  
Relative Growth Rate ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Net Assimilation Rate ◽  
Assimilation Rate ◽  
Relative Growth ◽  
Minimum Requirements ◽  
Net Assimilation ◽  
Pasture Plants

The results of a pot-culture experiment in which subterranean clover was grown on a coarse siliceous sand slightly acid in reaction are presented. Maximum yields resulted from application of potassium, together with either molybdenum or lime. The lime X molybdenum interaction was almost always negative, but its magnitude varied with time and potassium: in the absence of potassium it diminished in magnitude, but increased markedly in its presence. The lime X potassium and molybdenum X potassium interactions were strongly positive during the later stages of growth, but only in the absence of molybdenum and lime respectively. The effects of treatment on leaf-weight and leaf-area ratio were not closely related to those on relative growth rate. The latter were determined primarily by treatment effects on net assimilation rate. Both relative growth rate and net assimilation rate were increased by potassium. The results provide further support for the findings of Anderson and Oertel (1946) that, in legumes, nitrogen is the primary nutrient concerned in the response to lime and molybdenum, and that the molybdenum concentration gives little indication of the minimum requirements for satisfactory growth. The possible effect of lime on the transport of molybdenum from roots to tops is discussed.

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