scholarly journals TEMPERATURE EFFECTS ON GERMINATION OF 'GRASSLANDS MAKU' LOTUS AND OTHER EXPERIMENTAL LOTUS SELECTIONS

Author(s):  
J.F.L. Charlton

The germination rate of 'Grasslands Maku' lotus (Lotus pedunculatus Cav. syn L uliginosus) was assessed at constant temperatures of 20°C, 15°C, 10°C and a fluctuating temperature of 5/10°C (16 h/8 h per day). Germmation rate declined with temperature. Maximum germmation level was reached by 2 weeks at 20°C and 15°C. but at 10°C only 30% of seeds, and at 5/1O"C only 1% had germinated by this stage. Large seeds of Maku germinated faster than small seeds. Seedlot thousand seed weights of Maku lotus parent plants varied from 0.78 to 0.96 g and germmation rates of these lots at 5/10°C were associated wth seed size. Maku and 4 other lotus selections had much lower germination rates than two Lotus corniculatus cultivars and an interspecific hybrid selection G.4712. G.4702 (another tetraploid) germinated more rapidly than other lotus selections and Maku. These results indicate the need for production of quality Maku lotus seed, especially in terms of seed size, and for selection to improve germination rate. Keywords: Maku lotus, germination, temperature

1983 ◽  
Vol 63 (4) ◽  
pp. 1063-1065 ◽  
Author(s):  
Z. P. KONDRA ◽  
D. C. CAMPBELL ◽  
JANE R. KING

Seed of Brassica campestris L. has a significantly lower germination percent and germination rate than B. napus, especially at low temperatures. Significant differences among genotypes within species were demonstrated for both characteristics.Key words: Rapeseed, germination, temperature effects


Author(s):  
J.F.L.Charlton J.G. Hampton ◽  
D.J. Scott

Percentage germination and germination rate (days to 75% germination) of 14 'Grasslands' cultivars from 9 grass species were assessed at constant temperatures of 5,10,15,20,25,3O"C and a fluctuating temperature of S/lO"C. Ryegrass germination did not differ significantly within the range of temperatures used. Germination of Kahu timothy and Maru phalaris was reduced at or below 10°C and at 30°C. Raki paspalum failed to germinate below 15°C. The germination of Apanui and Wana cocksfoot and Matua prairie grass was reduced at 30°C. Germination rates for all species slowed as temperature moved away from the optimum, as did the number of days to the start of germination. Germination rate was greatest for the ryegrasses at all temperatures; for all other species the order was timothy, tall fescue> phalaris prairie grass and cocksfoot at lO"C, and timothy > phalaris, prairie grass>cocksfoot >tall fescue at 5°C. The implications of these results for pasture establishment are discussed. Keywords: germination, germination rate, temperature, temperate grasses, pasture establishment.


Author(s):  
J.G. Hampton ◽  
J.F.L. Charlton ◽  
D.D. Bell ◽  
D.J. Scott

Percentage germination and germination rate (days to 75% germination) of 14 herbage cultivars from 5 legume species were assessed at constant temperatures of 5°, 10°, 15°, 20° and a fluctuating temperature of 5/1O°C. The percentage germination of white clover, red clover and lucerne was not affected by temperature. Germination of Woogenellup subterranean clover was reduced at 5"C, the germination of Mt Barker subterranean clover was reduced at 2O°C, and the germination of Maku lotus was reduced at 5°C and 5/10°C. Germination rates for all species slowed as temperatures moved away from the optimum, as did the number of days to the start of growth. The species order for germination rate was lucerne, white clover >subterranean clover > red clover >lotus at 10° and 5/1O°C, and subterranean clover (except cv. Woogenellup), white clover, lucerne>red clover>lotus at 5°C. Germination rates differed between subterranean clover cultivars, and also between individual seedlots of subterranean clover, red and white clover and lotus, particularly at 5°C. The implications of these results for pasture establishment are discussed. Keywords: germination rate, pasture establishment


1996 ◽  
Vol 74 (4) ◽  
pp. 568-572 ◽  
Author(s):  
Stefan Andersson

The present study of the winter annual Crepis tectorum examines the relationship between seed (achene) size and the extent to which seeds resist germination during the year of their production. I carried out two seed burial experiments, one at an outcrop site occupied by a small-seeded population, and another in an experimental garden with soil from the same field site, with seeds representing the local population and a segregating generation of a cross between two other populations. Using logistic regression with data corrected for seed viability, I found an association between small seed size and failure to germinate in the first autumn. The small seed size characterizing many outcrop populations may have evolved as a response to selection for delaying germination in a habitat subject to unpredictable droughts during the growth season. Keywords: Crepis tectorum, germination, seed bank, seed size.


2019 ◽  
Vol 49 ◽  
Author(s):  
Fábio Steiner ◽  
Alan Mario Zuffo ◽  
Aécio Busch ◽  
Tiago de Oliveira Sousa ◽  
Tiago Zoz

ABSTRACT Seed size is an important indicator of physiological quality, since it may affect seed germination and seedling growth, especially under stress conditions. This study aimed to investigate the effects of seed size on germination and initial seedling growth, under salinity and water stress conditions. The treatments were arranged in a completely randomized design, in a 3 × 3 factorial scheme: three seed size classes (small, medium and large) and three stress treatments (control, saline or water stress), with four replicates. Water and salt stresses do not reduce the germination rate of medium and large seeds; however, the germination rate of small seeds is reduced under salt stress conditions. Drought stress drastically reduces the shoot growth of seedlings regardless of seed size, whereas root growth is higher in seedlings from medium and large seeds under water stress conditions. Under non-stressful environments, the use of large seeds is preferable, resulting in more vigorous seedlings with a greater dry matter accumulation. Medium-size seeds are more adapted to adverse environmental conditions and, therefore, should be used under conditions of water shortage and salt excess in the soil at sowing time. Seedlings are more tolerant to salinity than to water stress during the germination stage and initial growth under laboratory conditions.


1991 ◽  
Vol 42 (5) ◽  
pp. 893 ◽  
Author(s):  
DC Edmeades ◽  
FPC Blamey ◽  
CJ Asher ◽  
DG Edwards

Ten temperate pasture legumes inoculated with appropriate rhizobia were grown for 31 days in flowing solution culture. Solution ionic strength was approximately 2700 8M and contained inorganic nitrogen (150 , 8M NO3-) only at the commencement of the experiment. Solution pH was maintained at 4.5, 5.0, 5.5 and 6.0. Also, five aluminium (Al) treatments were imposed, with nominal Al concentrations of 0, 3, 6, 12 and 24 8M (2.5, 7.1, 8.3, 11.2 and 24.7 8M Al measured) at pH 4.5. Solution pH <6 . 0 markedly reduced total dry mass (TDM) in all cultivars of white clover (Trifolium repens) cvv. 'Grasslands Pitau, Huia, G18 and Tahora' and red clover (Trifolium pratense) cvv. 'Grassland Turoa and Pawera', and to a lesser extent in the two subterranean clover (Trifolium subterraneum) cvv. 'Tallarook and Woogenellup'. In contrast, solution pH had no effect on the growth of Lotus corniculatus cv. Maitland, while Lotus pedunculatus cv. Maku grew best at pH 4.5. Lotus pedunculatus cv. Maku grew best in solution where the sum of the activities of the monomeric Al species {Alm} was maintained at 5.9 8M. The growth of all other species was decreased with Al in solution, a 50% reduction in TDM being associated with c. 6 8M {Alm] for white clover and subterranean clover, and c. 3 8M in red clover and Lotus corniculatus cv. Maitland.


1985 ◽  
Vol 15 (6) ◽  
pp. 1109-1115 ◽  
Author(s):  
Frank C. Sorensen ◽  
Robert K. Campbell

Different mean seed weights were produced within each of 10 young Douglas-fir trees by leaving some developing cones unbagged and enclosing others in Kraft paper bags for two different durations. On the average, 10 days in the bag increased filled-seed weight by about 1%. Unbagged cones and cones from the 117-day bagging duration were wind pollinated. Seeds from these cones were, therefore, of comparable genetic makeup and were used in further nursery growth tests. To eliminate the effect of germination rate or time, samples of filled seeds from each treatment on each parent tree were sown as germinant seedlings on one date. Cotyledon number was counted and 1st-year epicotyl lengths and 2nd-year total heights were measured on all seedlings. Seedling volumes were estimated by assuming diameters were proportional to heights. On the average, bagging cones for 117 days increased seed weight by 10.7%, 1st-year epicotyl length by 9.1%, and 2-year total height by 4.0%. All differences were statistically significant. Results were compared with other reports of the relations between seed weight and growth and reasons for inconsistencies were discussed. Size differences were projected to later ages with a growth model and practical implications of long-term seed effects on plant size, of increasing seed size through cultural techniques, and of grading seed lots by size were considered.


2014 ◽  
Vol 92 (2) ◽  
pp. 281 ◽  
Author(s):  
Martha Cervantes ◽  
Eliane Ceccon ◽  
Consuelo Bonfil

<p><span style="font-size: medium;"><span style="font-family: Times New Roman;">Studies on propagation of trees of Tropical Dry Forests are scarce in Mexico, besides, the provenance of seeds used in reforestation programs is generally unknown or poorly addressed. Knowledge on seed germination patterns of different provenances, and how they change through time, is useful to identify adequate sources of seeds and to develop seed collection and storage programs under the low-tech conditions prevailing in most rural nurseries. We evaluated seed size variation and germination of stored seeds from three different provenances per species in <em>Acacia bilimekii</em>, <em>Haematoxylum brasiletto</em>, <em>Lysiloma acapulcense</em>, and<em> L. divaricatum</em>.<em> </em>Seeds were collected in four sites in the Tropical Dry Forest of Morelos, Mexico, and were stored at room temperature; seed size was estimated through the volume of 75 seeds per provenance/species. Seed germination tests were made periodically from six to 24 months after storage and the effects of provenance and storage time on germination were analyzed using Anovas. There were significant differences in seed size among provenances in all species, while the effect of provenance on germination rate was significant in three of them. Germination rate changed with storage time among species and provenances. After 24 months, germination capacity was still ≥ 50% in all provenances of the two <em>Lysiloma</em> species, but in <em>A.</em> <em>bilimekii</em> there were large differences among provenances. Mean germination capacity was low in <em>H. brasiletto</em> after six months. More research on seed germination and storage of a larger set of species and provenances is needed to restore the Mexican tropical dry forests. </span></span></p>


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