The inhibitory effect of light on seed development in subterranean clover (Trifolium subterraneum L.)

1976 ◽  
Vol 27 (2) ◽  
pp. 207 ◽  
Author(s):  
GB Taylor
Keyword(s):  
Seed Development ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Moisture Stress ◽  
Inhibitory Effect ◽  
Atmospheric Moisture ◽  
Dark Treatment ◽  
Poor Seed ◽  
Development Processes ◽  
Effect Of Light

Explanations were sought for the poor seed development commonly found in unburied burrs of subterranean clover. In the first of two experiments, the effects of light and of atmospheric moisture stress on seed development in subterranean clover (cv. Daliak) were examined. Burrs produced from spaced laterals were enclosed in plastic tubes variously shaded to permit the entry of 0, 5, 19, 48 and 100% daylight. The tubes were further allocated to two groups. Air was continuously passed through tubes of one group to produce an atmospheric moisture stress, while those of the other group were not subjected to air flow. There was a marked effect of light on seed development. Mean seed weight was reduced from c. 11 mg in the dark treatment to 4 mg at only 5% daylight and to 2 mg in the 100% daylight treatment. Seed numbers were reduced significantly, from four to c. two seeds per burr, in the 100% daylight treatment only. There was virtually no effect of atmospheric moisture stress on either seed set or seed size. In the second experiment, a study was made of the effect of timing of burr burial on seed development processes. Fertilization does not appear to be implicated but both cell division and cell enlargement were influenced by the state of burial and, presumably, by light.

The effect of some environmental conditions on seed development and hard-seededness in subterranean clover (Trifolium subterraneum L.)

1979 ◽  
Vol 30 (1) ◽  
pp. 65 ◽  
Author(s):  
GB Taylor ◽  
MJ Palmer
Keyword(s):  
Seed Development ◽  
Seed Size ◽  
Field Experiments ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Moisture Stress ◽  
Effect Of Temperature ◽  
Temperature Regimes ◽  
Increasing Temperature ◽  
Dry Out

Subterranean clover (cv. Daliak) was grown in boxes with provision for unrestricted lateral growth. At the commencement of flowering, plants were allocated to three day/night temperature regimes of 12/7°, 18/13° and 24/19°C in controlled-temperature glasshouses and well watered until maturity (unstressed). In two additional treatments at 18/13°, plants were either subjected to intermittent moisture stress throughout the flowering period (stressed) or well watered for the first 6 weeks of flowering and then allowed to dry out (droughted). Increasing temperature resulted in more rapid inflorescence production, seed development and earlier plant maturation. The overall mean seed size was lower at 24/19° than at the other two temperatures. The stressed and droughted treatments produced fewer and smaller seeds than the corresponding unstressed treatment. There was a small effect of temperature on the degree of hard-seededness as determined from the mean softening time of seed subjected to daily alternating temperatures of 60/15°. Softening time was not significantly affected by watering treatments. There were small differences in softening time due to the position of the burr on the lateral, with a slight trend for seeds from the first-formed burrs to soften more rapidly. Most of the variation in softening time between seeds was due to variation within burrs. The sequence of seed softening within burrs was related to seed size, the larger seeds generally softening first, but no single regression could be used to describe this relationship for different burr positions or treatments. The absence of major treatment effects on the degree of hard-seededness indicates that varying the length of the seed development period does not necessarily result in differences in hard-seededness, as has been suggested from field experiments.

The inhibitory effect of light on seed and burr development in several species of Trifolium

1979 ◽  
Vol 30 (5) ◽  
pp. 895 ◽  
Author(s):  
GB Taylor
Keyword(s):  
Light Intensity ◽  
Seed Development ◽  
Subterranean Clover ◽  
Light Response ◽  
Inhibitory Effect ◽  
Low Light ◽  
Effect Of Light

The effect of light on seed and burr development was studied in 20 genotypes from four species of Trifolium. Burrs produced from spaced laterals were enclosed in plastic tubes variously shaded to produce a range of light treatments. Light inhibited seed development to varying degrees in a range of subterranean clovers, which included strains of T. israeliticum and of all three subspecies of T. subterraneum. In four strains studied intensively the weight of seeds per burr decreased linearly with increases in the logarithm of the light intensity. Light had no effect on seed development in two other geocarpic species, T. batmanicum and T. globosum, which do not actually bury their burrs. The weight of both the pod walls (pericarps) and the sterile calyces was reduced by light in all strains of T. subterraneum. Light also reduced the weight of pod walls in T. israeliticum but had little effect on the production of sterile calyces. Variation in the pattern of light response between plants of the Seaton Park strain of T. subterraneum was found to be associated with genetically distinct lines. Four of the subterranean clover strains commonly produced twin-seeded pods in dark and low light treatments. The incidence of twinning in these strains appeared to be greater than that normally encountered in buried burrs. The ranking of strains of T. subterraneum for susceptibility to light agreed reasonably well with the ranking of the same strains, by others, for seed development above ground. Seaton Park and, to a lesser extent, Dinninup were exceptions in that they were more severely inhibited by light than by lack of burr burial. It is suggested that another factor in addition to light may be involved in the response to burr burial.

The growth of barley grass (Hordeum leporinum) in annual pasture. 3. Some factors affecting balance with subterranean clover (Trifolium subterraneum)

1968 ◽  
Vol 8 (35) ◽  
pp. 702 ◽  
Author(s):  
DF Smith
Keyword(s):  
Soil Nitrogen ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Moisture Stress ◽  
Nitrogen Addition ◽  
The Other ◽  
Early Start ◽  
Factors Affecting ◽  
Two Factors ◽  
Hordeum Leporinum

Mixed swards of barley grass (Hordeum leporinum) and subterranean clover (Trifolium subterraneum) of two densities were grown at two levels of nitrogen. Growth was started at two different times mid- April and mid-May-and at each time half the plots were subjected to moisture stress. The swards were harvested after nine weeks of growth. The survival of clover plants was reduced by an early start, moisture stress and nitrogen addition : much more so than barley grass. The root : shoot ratios of both species were calculated ; both showed some sensitivity to the time of break and moisture stress, and the grass was also affected by the other two factors. Total sward production and the ratios of clover to grass varied widely Grass daminance was favoured by moisture stress or a late break, and both of these factors tended to override the effect of higher soil nitrogen in determining clover-grass balance. Total sward production more dependent on density than any other factor, especially with the later start. Higher nitrogen was effective in boosting production only if the break was early and there was no moisture stress.

Seed-setting in subterranean clover (Trifolium subterraneum L.) 1. The importance of the microevironment

1957 ◽  
Vol 8 (5) ◽  
pp. 433 ◽  
Author(s):  
JJ Yates
Keyword(s):  
Seed Development ◽  
Surface Soil ◽  
Subterranean Clover ◽  
Soil Surface ◽  
Trifolium Subterraneum ◽  
Protective Effects ◽  
Percentage Germination ◽  
Seed Setting ◽  
Before And After ◽  
Mature Seeds

An investigation was made of the relative efficiency of above- and belowground seeding, under unfavourable environmental conditions, in the subterranean clover variety Red Leaf, which normally sets some seed above and some below the ground. The experiment included artificial shielding of burrs in sponge rubber to simulate the protective effects of natural burial. Seed-setting, expressed in terms of mature seeds as percentage of reflexed florets, was considerably better when development occurred at or below the soil surface, or when burrs were enclosed in rubber, than when untreated burrs did not come in contact with the soil.The presence of moisture in the surface soil improved seed-setting above the ground. Breakdown of seed-forming processes occurred both before and after the stage at which seed development could be detected. Seeds formed above the surface were of light weight and gave very poor germination; seeds which had been buried or enclosed in rubber were much heavier and percentage germination was high; and those formed on the surface were intermediate.The results emphasize the importance of the microenvironment of individual inflorescences and burrs, and the value of protective or modifying influences, during the whole period of seed development in this species.

Response of subterranean clover, balansa clover, and gland clover to lime when grown in mixtures on an acid soil

2008 ◽  
Vol 59 (9) ◽  
pp. 824 ◽  
Author(s):  
R. C. Hayes ◽  
B. S. Dear ◽  
B. A. Orchard ◽  
M. B. Peoples ◽  
P. L. Eberbach
Keyword(s):  
Seed Yield ◽  
N2 Fixation ◽  
Acid Soil ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Moisture Stress ◽  
Soil Conditions ◽  
Pasture Production ◽  
Mn Toxicity ◽  
Annual Legumes

This study compared the relative tolerances of subterranean clover (Trifolium subterraneum L.), balansa clover (T. michelianum Savi.), and gland clover (T. glanduliferum Boiss.) to acid soil conditions. Seed yield, seedling density, herbage production, N2 fixation, and herbage mineral composition of the 3 legumes were assessed when grown on an acid soil (pHCa of 4.3 and 15% exchangeable Al [0–0.10 m]) with and without the addition of lime (CaCO3). Annual legume species were sown in a mixed sward together with burr medic (Medicago polymorpha L.), and in mixtures with either lucerne (Medicago sativa L.), chicory (Cichorium intybus L.), or phalaris (Phalaris aquatica L.). Due to drier than average seasonal conditions, none of the perennial species persisted beyond the first summer. Lime increased the herbage production of annual legumes by 18–22% and total pasture production by 14% in both 2002 and 2003. Subterranean clover was the most tolerant of the annual legumes to acid soil conditions, showing no visible toxicity symptoms and no response to lime in terms of seed yield. In contrast, both balansa and gland clovers exhibited visual symptoms of manganese toxicity in the absence of lime, with Mn concentrations in the shoots of 817 mg/kg and 626 mg/kg, respectively. Both species responded positively to lime with seed yields increasing by 45% and 124%, respectively. Lime increased the proportion of herbage N derived from N2 fixation by subterranean clover from 29 to 40% and by gland clover from 30 to 43%. Lime had no effect on the proportion of N2 fixed by balansa clover (29–31%), suggesting a suboptimal symbiosis of rhizobia with that species. Adding chicory or phalaris to the pasture mix increased sward herbage production in the establishment year by 39% and 21%, respectively. Based on leaf symptoms and herbage yield responses to lime, Mn toxicity was present in lucerne with tissue levels of up to 916 mg/kg, but no symptoms were observed in chicory (1129 mg/kg) or phalaris (403 mg/kg). Chicory and phalaris were more tolerant of acidity and high levels of Mn than lucerne, gland clover, and balansa clover. The study highlighted the value of the small-seeded annual legumes, balansa clover and gland clover, to the production of mixed pasture swards even in drier than average seasonal conditions. Although more sensitive to acid soils than subterranean clover, they set a greater number of seeds and, in the case of balansa clover, a greater weight of seed under moisture stress in the establishment year than the larger seeded subterranean clover.

The effect of burr burial on the seed of some early maturing subterranean clover cultivars

1971 ◽  
Vol 11 (48) ◽  
pp. 35 ◽  
Author(s):  
BJ Quinlivan ◽  
CM Francis
Keyword(s):  
Seed Development ◽  
Seed Weight ◽  
Seed Viability ◽  
Subterranean Clover ◽  
Soil Surface ◽  
Trifolium Subterraneum ◽  
Cultivar Differences ◽  
Seed Content ◽  
Early Maturing ◽  
Agricultural Regions

Seven early maturing cultivars of subterranean clover (Trifolium subterraneum) showed large between cultivar differences in terms of burr and seed development above the soil surface. The indices used for determining differences between buried and unburied burrs were burr and seed weight, and seed viability and impermeability. With all cultivars seed formed above the soil surface weighed less and had a lower viable and impermeable seed content. The results are discussed in terms of the selection and breeding of subterranean clover cultivars suitable for the low rainfall agricultural regions of Western Australia

Change in stomatal resistance and water use in subterranean clover (Trifolium subterraneum L.) in response to broadleaf herbicides

1996 ◽  
Vol 47 (4) ◽  
pp. 625 ◽  
Author(s):  
BS Dear ◽  
GA Sandral ◽  
NE Coombes
Keyword(s):  
Water Use ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Moisture Stress ◽  
Stomatal Resistance ◽  
Herbicide Application ◽  
Herbicide Treatments ◽  
Daily Water ◽  
Saving Effect ◽  
Reduced Water

The effect of 5 broadleaf herbicides on the water use and stomatal resistance of 2 cultivars of subterranean clover (Trifolium subterraneum L.) was examined in a glasshouse study. The herbicide treatments 2,4-DB, MCPA, bromoxynil, MCPA+terbutryn, and MCPA+diuron were applied at 6 rates at 2 times (14 May, 14 June) to plants at 2 leaf stages (3-4 and 8-10 leaves). Each of the herbicides reduced water use by the clover within 24 h, the size of the reduction increasing with the rate of herbicide applied. The herbicide treatments MCPA+terbutryn, MCPA+diuron, and bromoxynil caused the largest reductions (44-52%) in total water use over the 30-day period when applied at the recommended rate, and MCPA and 2,4-DB the least reduction (16-22%). Stomatal resistance increased substantially within 2 days of application of each of the herbicides. The magnitude of the change differed with herbicide and increased with herbicide rate. The effect of the herbicides on stomatal resistance declined 10-20 days after herbicide application in all treatments except 2,4-DB, but stomatal resistance of all herbicide-treated plants was still higher than the control 30 days after herbicide application. The herbicides LICPA+terbutryn and LlCPA+diuron and bromoxynil caused the largest increase in stomatal resistance and 2,4-DB the least. Stomatal resistance was found to be highly negatively correlated with daily water use by the clover plants at 2 days (r = -0.84, P < 0.01) and 30 days (r = -0.88, P < 0.01) after herbicide application. All of the herbicides reduced the LA1 of the plants, the effect increasing as the herbicide rate increased. Herbicide and herbicide rate had the largest effect on both water use and stomatal resistance; the effect of cultivar, leaf stage, and spraying time accounted for a relatively small proportion of the variance. The findings support the hypothesis that some broadleaf herbicides can result in a water-saving effect in subterranean clover swards through increasing stomatal resistance and decreasing the LAI, thereby potentially reducing moisture stress during seed set.

The effects of a continued water supply during and beyond seed development on seed production and losses in subterranean clover swards

1980 ◽  
Vol 31 (2) ◽  
pp. 287 ◽  
Author(s):  
WJ Collins ◽  
BJ Quinlivan
Keyword(s):  
Seed Germination ◽  
Water Supply ◽  
Seed Development ◽  
Subterranean Clover ◽  
Moisture Stress ◽  
Pathogenic Microorganisms ◽  
Marked Decline ◽  
Beginning Of Flowering ◽  
Seed Yields ◽  
Number Of Seeds

Four strains of subterranean clover were grown in swards and mown regularly until the beginning of flowering. During the period of flowering and seed development, the swards were irrigated as required to prevent moisture stress. Watering was then continued to keep the burrs and seeds moist for a further 5 months. Depending on the strain, seed yields reached a peak between 74 days and 86 days after the onset of flowering (late August-early September). Then followed a sudden and marked decline in both the amount and number of seeds present in the four strains. By the end of February less than 20% of the seeds produced were still present in the soil. Seed germination accounted for less than 50% of the seed losses. The remainder (unrecovered seed) was presumably lost as a result of attack by pathogenic microorganisms in the soil. The results suggest that it may be difficult to obtain maximum seed yields in swards of subterranean clover. Even a relatively small (3 weeks) decrease or increase in the period for which moisture is available, compared with the optimum, can lead to markedly reduced seed yields.

PERFORMANCE OF SUBTERRANEAN AND WHITE CLOVER VARIETIES IN DRY HILL COUNTRY

1986 ◽  
pp. 53-62 ◽  
Author(s):  
D.F. Chapman ◽  
G.W. Sheath ◽  
M.J. Macfarlane ◽  
P.J. Rumball ◽  
B.M.Cooper G. Crouchley ◽  
...  
Keyword(s):  
New Zealand ◽  
White Clover ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Moisture Stress ◽  
Hill Country ◽  
Cold Environments ◽  
Dry Conditions ◽  
Country Selection ◽  
Firm Selection

Nine subterranean clover cultivars and 10 white clover varieties, differing in characters such as morphology and flowering date (sub clover), or growth habit and seeding ability (white clover), where evaluated for persistence and production at 8 summer-dry hill country sites. Results for the first 3-4 years suggest the sub clovers on the New Zealand Acceptable Herbage Cultivars List (Mt Barker, Tallarook, Woogenellup, Glare) should be revised. Regeneration of Woogenellup and Glare was consistently poor, while Tallarook performed well at most sites. The current unavailability of Tallarook seed means Mt Barker is the only effechve option for grasslands in most of New Zealand. Cultivars of the sub clover subspecies yanmnicum (Larisa, Trikkala) showed promise for winter~wet, summer dry environments, as did Nangeela in winter-cold environments. A late-flowering, prostrate, low oestrogenic sub clover similar to Tallarook would be well suited to large areas of summer-dry hill country. There is a clear need for a white clover cultivar adapted to summer-dry hill country as none of the varieties tested survived severe moisture stress at 2 sites (Hawke's Bay, North Canterbury), and none performed consistently well at the other sites. New Zealand vaneties (Hula, Pitau, G18 and a hill country selection) showed best persistence and production. The overseas cultivars Haifa, Tamar, Louisiana and Clarence Valley, which are all adapted to dry conditions in their country of origin, were consistently poor. Firm selection criteria for dry hill country were not identified, though stolen density and seeding ability should be incorporated and the strong influence of management and soil fertility on genotype performance must be recognised. Keywords: subterranean clover (Trifolium subterraneum L.), white clover (Trifolium repens L.), hill country, dryland, cultivars, persistence, genotype-environmental interaction.

scholarly journals The Effect of Light on Zinc Deficiency in Subterranean Clover (Trifolium Subterraneum L.)

1955 ◽  
Vol 8 (3) ◽  
pp. 344 ◽  
Author(s):  
PG Ozanne
Keyword(s):  
Zinc Deficiency ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Dry Weight ◽  
Daily Maximum ◽  
Light Intensities ◽  
The Mean ◽  
Zinc Response ◽  
The Difference ◽  
Effect Of Light

The effects of light on zinc response were investigated by growing subtermnean clover under daylight of various intensities. Plants were grown in limed Muchea sand and the zinc response was measured as the difference in dry weight between plants with and without added zinc. The light intensities are given as the mean daily maximum intensities.

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