The relationship between temperature fluctuations and the softening of hard seeds of some legume species

1966 ◽  
Vol 17 (5) ◽  
pp. 625 ◽  
Author(s):  
BJ Quinlivan
Keyword(s):  
Critical Factor ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Temperature Fluctuations ◽  
Maximum Temperature ◽  
Hard Seeds ◽  
Maximum Temperatures ◽  
The Relationship ◽  
Fluctuating Temperatures ◽  
Main Factor

Hard seeds of subterranean clover (Trifolium subterraneum L.) of the Geraldton and Bacchus Marsh strains, and of West Australian blue lupin (Lupinus varius L.), were subjected to various daily fluctuating temperatures within the normal summer environmental range (15–75°C). The main factor determining the rate of softening of the hard seeds was the maxinlum temperature of the fluctuation. Provided the temperature changed by some 15°C , the amplitude of the fluctuation did not appear to be a critical factor. The softening of hard seeds of any particular species did not commence until the amplitude of the temperature fluctuation, or the maximum temperature, reached a certain level, which in turn varied with the species. Beyond this level the rate of softening increased with increasing fluctuations to a point where the rate became very rapid, and thereafter wider fluctuations or higher maximum temperatures did not give significant increases.

The influence of the growing season and the following dry season on the hardseeedness of subterranean clover in different environments

1965 ◽  
Vol 16 (3) ◽  
pp. 277 ◽  
Author(s):  
BN Quinlivan
Keyword(s):  
Surface Temperature ◽  
Critical Factor ◽  
Subterranean Clover ◽  
Soil Surface ◽  
Trifolium Subterraneum ◽  
Temperature Fluctuations ◽  
Growing Season ◽  
Growing Period ◽  
Hard Seeds ◽  
Soil Surface Temperature

The length of the growing period in the spring months appears to be a critical factor in the development of hardseededness in subterranean clover (Trifolium subterraneum L.). Environments with relatively long spring growing periods cause a higher proportion of hard seeds to form at field maturity, and increase the resistance which these hard seeds are capable of offering to the softening effects of the following summer environment. During the dry summer period the rate of softening of hard seeds is determined, not only by the previous growing season but also by the summer environment itself. Hot summer environments with wide soil surface temperature fluctuations are conducive to a relatively rapid rate of softening. Grazing or removal of the dry topgrowth from a pasture during the summer increases the daily soil surface temperature fluctuations, and results in the hard seeds softening at an increased rate. Differences in the overall environment manifest themselves in terms of site and seasonal variation in the proportion of hard seeds which survive beyond the opening of the following growing season. The scope for variation is wide, and this has agronomic significance from the aspect of long-term persistence of the species.

Irrigated pasture productivity and its variability in the Shepparton region of northern Victoria

1983 ◽  
Vol 23 (121) ◽  
pp. 131 ◽  
Author(s):  
CR Stockdale
Keyword(s):  
Environmental Factors ◽  
Growth Curves ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Maximum Temperature ◽  
Lolium Rigidum ◽  
Growing Period ◽  
Wimmera Ryegrass ◽  
Maximum Temperatures ◽  
Pasture Productivity

The seasonal distribution and variability of growth of three types of irrigated pastures were measured at Kyabram over a period of up to seven years. The pasture types studied were (1) paspalum (Paspalum dilatatum)-dominant perennial pasture, (2) ryegrass (Lolium perenne)/clover (Trifolium repens) perennial pasture, and (3) annual pasture based on subterranean clover (Trifolium subterraneum) and Wimmera ryegrass (Lolium rigidum). The influence of environmental factors on the year-to-year variability in monthly growth rates was also examined. Annual growth curves were constructed for each pasture type, and examination of the variability about each monthly mean indicated that the spring months, and October in particular, were the most variable months for pasture growth. Environmental factors were found to account for part of the year-to-year variation in pasture growth of paspalum pastures in August, September, October, November and April. Higher mean maximum temperatures significantly increased growth in September, October and April, with the greatest response occurring in October; hours of sunshine was the significant factor influencing growth in August and November. Annual pasture growth also responded to changes in mean maximum temperature or hours of sunshine in September and October. The comparative mean annual production of paspalum pasture, ryegrass/clover pasture and annual pasture was 18.3, 18.3 and 11.0 t DM/ha, respectively. These levels of production represented 1.1, 1.2 and 1.6% conversion of photosynthetically active radiation during the growing period of the three pasture types, respectively. These levels of productivity and the animal production that should result, suggest that the pasture productivity on many irrigated dairy farms is either very low or the pasture that is grown is inefficiently utilized. Because animal productivity depends on pasture productivity more than any other single factor, farmers should make improvement of pasture growth their major aim while having regard for the variability in growth that can result from variations in environmental factors.

The action of temperature fluctuations on hard seeds of subterranean clover

1971 ◽  
Vol 11 (51) ◽  
pp. 440 ◽  
Author(s):  
MW Hagon
Keyword(s):  
No Reduction ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Temperature Fluctuations ◽  
Specific Region ◽  
Daily Temperature ◽  
Laboratory Conditions ◽  
Hard Seeds ◽  
Cycle Lengths ◽  
Daily Temperature Fluctuations

Burrs of three cultivars of subterranean clover (Trifolium subterraneum) were placed in soil in a cold frame at Canberra so that they were subjected to daily temperature fluctuations of the order of 20-54�C. After three months and eight months the proportion of permeable seeds was significantly increased. Such seeds were conductive to water at one specific region of the testa-the strophiole. In a further experiment, under laboratory conditions, hard seeds were subjected to temperature fluctuations of 23-60�C with cycle lengths varying from 15 minutes to 1 hour. There was no reduction in the percentage of hard seeds except in two trials when that portion of each cycle at 60�C was greater than 45 minutes.

Effect of burial on the softening of hard seeds of subterranean clover

1984 ◽  
Vol 35 (2) ◽  
pp. 201 ◽  
Author(s):  
GB Taylor
Keyword(s):  
Subterranean Clover ◽  
Soil Surface ◽  
Trifolium Subterraneum ◽  
Temperature Fluctuations ◽  
The Other ◽  
Soil Tillage ◽  
Microbial Decomposition ◽  
Buried Seeds ◽  
Hard Seeds ◽  
Depth Of Burial

Burrs of eight varieties of subterranean clover (Trifolium subterraneum L.), which had experienced one summer at the soil surface, were placed on the soil surface and at depths of 2, 6 and 10 cm in the soil. The numbers of residual hard seeds were determined after 1, 2 and 3 years. The effects of laboratory treatment at a diurnally fluctuating temperature of 60/15�C on the softening of buried seeds and of seeds stored in the laboratory for 1 and 3 years were determined. Rate of seed softening in all varieties decreased with increasing depth of burial, apparently because the soil insulated the seeds from high soil surface temperatures. Few seeds of the varieties Northam and Geraldton softened during 3 years of burial at 6 or 10 cm; while, at the other extreme, few seeds of Yarloop survived 3 years at any depth. Some evidence was found for microbial decomposition of hard seeds in the field. Seeds softened more readily at 60/15�C (in the laboratory) as the preceding periods of either laboratory storage or field burial increased. Such storage or burial experiences have a preconditioning effect on hard seeds, making them more amenable to softening once they are subjected to wide diurnal temperature fluctuations. The results indicate that soil tillage associated with cropping should build up a useful soil seed reserve of the harder seeded varieties.

Response of defoliated swards of subterranean clover and yellow serradella to superphosphate applications

1991 ◽  
Vol 31 (6) ◽  
pp. 777
Author(s):  
MDA Bolland
Keyword(s):  
Field Experiment ◽  
Sandy Soil ◽  
Dry Matter ◽  
Maximum Yield ◽  
Subterranean Clover ◽  
Soil Surface ◽  
Trifolium Subterraneum ◽  
Herbage Yield ◽  
Ornithopus Compressus ◽  
The Relationship

The effect of superphosphate applications (0, 25, 50, 75, 100 and 125 kg P/ha to the soil surface) on the dry matter (DM) herbage production of dense swards of subterranean clover (Trifolium subterraneum cv. Junee) and yellow serradella (Ornithopus compressus cv. Tauro) was measured in a field experiment on deep, sandy soil in south-western Australia. The swards were defoliated with a reel mower at weekly intervals from 88 to 158 days after sowing, to a height of 2 cm for the first 9 cuts, 4 cm for the tenth cut and 5 cm for the eleventh cut. Yellow serradella was more productive than subterranean clover. Consequently, for the relationship between yield and the level of phosphorus (P) applied, yellow serradella supported larger maximum yields and required less P than subterranean clover, to produce the same DM herbage yield. Maximum yields of yellow serradella were 12-40% larger. To produce 70% of the maximum yield for yellow serradella at each harvest, yellow serradella required about 50% less P than subterranean clover. However, when yields were expressed as a percentage of the maximum yield measured for each species at each harvest, the relationship between yield and the level of P applied was similar for both species, and they had similar P requirements.

Effects of phosphorus on seed yields of subterranean clover, serradella and annual medics

1985 ◽  
Vol 25 (3) ◽  
pp. 595 ◽  
Author(s):  
MDA Bolland
Keyword(s):  
Seed Yield ◽  
Subterranean Clover ◽  
Average Weight ◽  
The Third ◽  
Hard Seeds ◽  
Annual Medics ◽  
Alternating Temperature ◽  
Seed Yields ◽  
The Relationship ◽  
Number Of Seeds

In three experiments located near Esperance, Western Australia, the effect of superphosphate phosphorus on seed yields of subterranean clover, serradella and annual medics was measured on newly-cleared soils, using low seeding rates. In two experiments, the relationship between seed yield and the amount of phosphorus applied was linear for subterranean clover and serradella; seed yields increasing by 7-24 kg/ha for each kg/ha of phosphorus applied, depending on species, strain or cultivar, and location. In the third experiment, seed yields of annual medic species also increased markedly with increasing amounts of applied superphosphate phosphorus, this response also depended on species and strain or cultivar, but the responses become less marked with increasing amounts of phosphorus. For the annual medic species, the phosphorus treatments had no effect on average weight of one burr, number of seeds per burr, weight of one seed, or the rate of softening of hard seeds as measured both in a 15/60� alternating temperature oven (one cycle/day) or for samples of burrs collected periodically during summer from the field. For all legumes, the appearance of first flowers was not affected by phosphorus treatment.

Effect of depth of burial on the longevity of hard seeds of subterranean clover and annual medics

1988 ◽  
Vol 28 (1) ◽  
pp. 77 ◽  
Author(s):  
GB Taylor ◽  
MA Ewing
Keyword(s):  
Subterranean Clover ◽  
Soil Surface ◽  
Trifolium Subterraneum ◽  
Barrel Medic ◽  
Hard Seeds ◽  
Burr Medic ◽  
Seed Reserves ◽  
Annual Medics ◽  
Depth Of Burial ◽  
Tillage Operations

Burrs of 3 cultivars of subterranean clover (Trifolium subterraneum) and 1 cultivar each of burr medic (Medicago polymorpha) and barrel medic (M. truncatula), which had experienced 1 summer at the soil surface, were placed on the soil surface and at depths of 2, 6 and 10 cm in the soil. The numbers of residual hard seeds were determined each year for up to 4 years. There was a marked reduction in the rate of seed softening in all 3 clover cultivars with increasing depth of burial. Whereas <20% of the seeds of the hardest seeded clover cultivar, Nungarin, survived 3 years at the soil surface, there was no significant decline in seed numbers during 4 years of burial at 10 cm. Even with cv. Geraldton, in which only 5% of seeds remained after 1 year of placement at the soil surface, 75% of seeds survived 4 years of burial at 10 cm. Hard seeds of both medic varieties were considerably more resilient than clover seeds at the soil surface, particularly during the first summer following seed set. However, burial had much less effect on their longevity, with no significant effect of burial to 2 cm in either medic, or of burial to 6 cm in the case of barrel medic. These results support earlier findings which showed that tillage operations associated with crop establishment which result in the burial of substantial proportions of subterranean clover seeds can lead to useful soil seed reserves. The much lesser effect of burial on seed softening of the medics, compared with subterranean clover, suggests that tillage operations will be less advantageous to medic persistence in leys.

Phosphate applied to soil increases the effectiveness of subsequent applications of phosphate for growing wheat shoots

1998 ◽  
Vol 38 (8) ◽  
pp. 865 ◽  
Author(s):  
M. D. A. Bolland ◽  
M. J. Baker
Keyword(s):  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Phosphorus Retention ◽  
Single Superphosphate ◽  
Mitscherlich Equation ◽  
Curvature Coefficient ◽  
Glasshouse Experiment ◽  
Phosphorus Application ◽  
The Relationship ◽  
Field Plots

Summary. Amounts of phosphorus ranging from 0 to 599 kg P/ha were applied as single (ordinary) superphosphate once only in 1976 to plots of a field experiment on a lateritic ironstone gravel sand. Subterranean clover (Trifolium subterraneum) and cereals (wheat, Triticum aestivum, and barley, Hordeum vulgare) were grown in rotation on the plots for 20 years after phosphorus application. In 1996, samples of the <2 mm fraction of the top 10 cm of soil were collected from the field plots to measure phosphorus retention by soil and for a glasshouse experiment. The phosphorus retention index, a measure of the capacity of the soil to sorb phosphorus, decreased from 35 to 2 mL/g as the amount of phosphorus applied 20 years previously increased from 0 to 599 kg/ha. In the glasshouse experiment, wheat was grown for 35 days in soil to which 9 amounts of freshly-applied powdered single superphosphate (0, 0.0125, 0.025, 0.05, 0.1, 0.2, 0.4, 0.8 and 1.6 g P/pot, for 1.8 kg soil/pot) were applied to the original phosphorus treatments. The value of the curvature coefficient of the Mitscherlich equation fitted to the relationship between yield of dried shoots and the amount of fresh-phosphorus applied increased with increasing amount of phosphorus applied 20 years previously. That is, the fresh-phosphorus treatments became more effective for producing dried wheat shoots as the amount of previously applied phosphorus increased.

Copper nutrition of subterranean clover (Trifolium subterraneum L. cv. Seaton Park). III. Effects of phosphorus supply on the relationship between copper concentrations in plant parts and yield

1981 ◽  
Vol 32 (2) ◽  
pp. 283 ◽  
Author(s):  
DJ Reuter ◽  
AD Robson ◽  
JF Loneragan ◽  
DJ Tranthim-Fryer
Keyword(s):  
Copper Deficiency ◽  
Phosphorus Deficiency ◽  
Potassium Phosphate ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Young Leaf ◽  
Plant Parts ◽  
High Concentrations ◽  
Four Levels ◽  
The Relationship

The effects of phosphorus supply on the relationship of copper supply with copper concentrations in various plant parts and yield of Seaton Park subterranean clover were examined. Plants were grown in a glasshouse for 40 and 74 days in pots with four levels of potassium phosphate (0, 13, 39, 65 mg phosphorus/pot) and six levels of copper sulfate (0, 50, 100, 200, 400, 800 pg copper/pot) added, in factorial combination, to a sand deficient in both phosphorus and copper. By increasing the phosphorus levels copper deficiency was induced partly by promoting growth and diluting copper concentrations in plants; and also by depressing copper absorption. Increasing phosphorus changed the distribution of copper in plant tops and the shape of curves relating copper concentration in whole plant tops to yield. At 39 mg phosphorus/pot, the relationship at Day 74 had a marked 'Piper-Steenbjerg' curvature, largely as a result of unusually high copper concentrations in the stems plus petioles of severely copper-deficient plants. At 65 mg phosphorus/pot, the relationship had no 'Piper-Steenbjerg' curvature for whole tops and only a relatively small curvature for stems plus petioles. The data suggests that 'Piper-Steenbjerg' curves in subterranean clover result primarily from high concentrations of copper in the stems plus petioles of severely deficient plants. At both harvests, young leaf blades had critical copper concentrations of around 3 �g copper/g at both 39 and 65 mg phosphorus/pot. However, copper-deficient plants with severe phosphorus deficiency did not respond to copper, and generally had copper concentrations below this critical level in all plant parts. The results confirm the value of copper analysis of young leaf blades for diagnosing copper deficiency in subterranean clover with moderately deficient to luxury supplies of phosphorus.

Fire effects on seed relaease and the emergence and establishment of seedlings in Banksia ericifolia. L.f

1981 ◽  
Vol 29 (5) ◽  
pp. 521 ◽  
Author(s):  
RA Bradstock ◽  
PJ Myerscough
Keyword(s):  
Seed Bank ◽  
Seedling Emergence ◽  
Fire Regimes ◽  
Fire Effects ◽  
Maximum Temperature ◽  
Fire Intensity ◽  
Fire Temperature ◽  
Banksia Ericifolia ◽  
Maximum Temperatures ◽  
The Relationship

Fire intensity and seasonality affected the release of seed in Banksia ericifolia L.f, and the post-fire emergence of seedlings. Mean maximum temperatures recorded in a heathland burn in May 1977 at heights of 0.5, 2 and 3 m were about 400, 275 and 175°C respectively. Variability in maximum temperature was dependent on the age and position of B. ericifolia stands. Release of seed held on B. ericifolia bushes increased significantly after fire. The proportion of seed released on unburnt controls stayed constant. Seeds were released earlier and quicker from cones exposed to high fire temperature maxima than from those exposed to low fire temperature maxima. Up to 80% of the seed bank was released 95 days after the fire. A greater proportion of the seed bank emerged and established as seedlings 5 months after the fire in May than after a fire the previous February. Seedling emergence and mortality were broadly related to rainfall over this period. The relationship between various fire regimes and abundance in B. ericifolia populations is discussed.

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