Seasonal changes in germination responses of buried seeds of Verbascum thapsus and V. blattaria and ecological implications

1981 ◽  
Vol 59 (9) ◽  
pp. 1769-1775 ◽  
Author(s):  
Jerry M. Baskin ◽  
Carol C. Baskin
Keyword(s):  
Seasonal Changes ◽  
Growing Season ◽  
Seasonal Temperature ◽  
Verbascum Thapsus ◽  
Germination Characteristics ◽  
Buried Seeds ◽  
Ecological Implications ◽  
Successional Species ◽  
Summer Temperatures ◽  
Spring Temperatures

In a 2-year study buried seeds of Verbascum thapsus and V. blattaria were exposed to natural seasonal temperature cycles, and at monthly intervals they were exhumed and tested in light and darkness over a range of alternating temperatures simulating those in the habitat throughout the growing season. At any time from spring to early autumn, seeds of both species germinated in light at prevailing habitat temperatures. Seeds of V. blattaria germinated in darkness in spring at spring temperatures but did not germinate in darkness at any temperature in summer or autumn. Unlike V. blattaria, seeds of V. thapsus germinated to 25–85% in darkness in summer at summer temperatures. In the second spring of burial, seeds of both species showed a reduction in ability to germinate in darkness at spring temperatures. Only 5% of the V. blattaria and 16% of the V. thapsus seeds germinated while they were buried. The germination characteristics are discussed in relation to the ecology of these two early successional species.

Seasonal Changes in the Germination Responses of Buried Witchgrass (Panicum capillare) Seeds

Weed Science ◽  
1986 ◽  
Vol 34 (1) ◽  
pp. 22-24 ◽  
Author(s):  
Jerry M. Baskin ◽  
Carol C. Baskin
Keyword(s):  
Seasonal Changes ◽  
Late Summer ◽  
Late Spring ◽  
Seasonal Temperature ◽  
Temperature Changes ◽  
Late Autumn ◽  
Buried Seeds ◽  
Autumn And Winter

Buried seeds of witchgrass (Panicum capillare L., # PANCA) exposed to natural seasonal temperature changes in Lexington, KY, for 0 to 35 months exhibited annual dormancy/nondormancy cycles. Seeds were dormant at maturity in early October. During burial in late autumn and winter, fresh seeds and those that had been buried for 1 and 2 years became nondormant. Nondormant seeds germinated from 76 to 100% in light at daily thermoperiods of 15/6, 20/10, 25/15, 30/15, and 35/20 C, while in darkness they germinated from 1 to 24%. In late spring, seeds lost the ability to germinate in darkness, and by late summer 63 to 100% of them had lost the ability to germinate in light. As seeds became nondormant, they germinated (in light) at high (35/20, 30/15 C) and then at lower (25/15, 20/10, and 15/6 C) temperatures. As seeds reentered dormancy, they lost the ability to germinate (in light) at 15/6 C and at higher thermoperiods 2 to 3 months later.

Seasonal changes in the germination responses of buried seeds of Barbarea vulgaris

1989 ◽  
Vol 67 (7) ◽  
pp. 2131-2134 ◽  
Author(s):  
Jerry M. Baskin ◽  
Carol C. Baskin
Keyword(s):  
Soil Moisture ◽  
Seasonal Changes ◽  
Soil Surface ◽  
Growing Season ◽  
Barbarea Vulgaris ◽  
Buried Seeds

In light, fresh seeds of Barbarea vulgaris germinated to 33–62% at 30:15 and 35:20 °C, and 0–5% at 15:5, 20:10, and 25:15 °C; in darkness, they germinated to 0–5% at all thermoperiods. Seeds were buried in pots of soil in mid-July 1983 and 1984 and kept in a greenhouse without temperature controls. Beginning on 1 August, seeds were exhumed monthly for 26.5 (1983 seeds) and 30.5 (1984 seeds) months and tested in light and darkness over the range of thermoperiods. Seeds after-ripened rapidly during the first 2 weeks of burial, and in August they germinated to 65 – 100% at all thermoperiods in light, but to only 0–3% in darkness. Throughout the study, seeds tested in light at the respective monthly thermoperiod germinated to 83 – 100% from April to October and to 45 – 100% in November and March. Thus, seeds brought to the soil surface at any time during the growing season can germinate when soil moisture is nonlimiting. Exhumed seeds germinated to 1 – 77% in darkness at July and August temperatures (35:20 °C) during July and August; however, they did not germinate while buried.

Dormancy patterns in buried seeds of Datura ferox and D. stramonium

1991 ◽  
Vol 69 (1) ◽  
pp. 173-179 ◽  
Author(s):  
O. Reisman-Berman ◽  
J. Kigel ◽  
B. Rubin
Keyword(s):  
Seasonal Changes ◽  
Soil Surface ◽  
Early Spring ◽  
Early Winter ◽  
Soil Layers ◽  
Primary Dormancy ◽  
Dry Storage ◽  
Buried Seeds ◽  
Summer Temperatures

Seasonal changes in seed dormancy of Datura ferox L. and D. stramonium L. were studied during 2 years in seeds buried in the field and compared with changes in dormancy of dry-stored seeds. Dormancy levels were evaluated by measuring the germination of exhumed and dry-stored seeds under 32:27 °C (nondormant seeds) or 32:12 °C (relatively dormant seeds). Levels of relative or full dormancy did not change during 2 years of dry storage in either species. Seed burial at 20 cm accelerated after-ripening, and primary dormancy disappeared earlier than at 5 cm. However, burial depths greater than 10 cm prevented germination in situ. This inhibition was not due to smaller daily fluctuations of soil temperature with increasing depth, since seeds buried at 20 cm and kept at 32:12 °C also failed to germinate. Transferring seeds to shallower soil layers allowed their germination. Cyclic seasonal changes in dormancy were found in buried seeds of D. ferox but not in D. stramonium. In D. ferox, dormancy was alleviated during the winter and germinability was maximal in early spring; the increase in dormancy was preceded by high late spring – summer temperatures. In D. stramonium most seeds near the soil surface germinated in the field in a brief flush in early winter, at temperatures under which D. ferox did not germinate. Key words: Datura, germination, dormancy, buried seeds, temperature.

Does Seed Dormancy Play a Role in the Germination Ecology ofRumex crispus?

Weed Science ◽  
1985 ◽  
Vol 33 (3) ◽  
pp. 340-343 ◽  
Author(s):  
Jerry M. Baskin ◽  
Carol C. Baskin
Keyword(s):  
Seed Dormancy ◽  
Growing Season ◽  
Seasonal Temperature ◽  
Rumex Crispus ◽  
Temperature Changes ◽  
Germination Ecology ◽  
Buried Seeds ◽  
Buried Seed

Seed dormancy does not play a role in the germination ecology of curly dock (Rumex crispusL. ♯ RUMCR). This study confirms reports that freshly matured seeds are nondormant, and it shows that buried seeds exposed to natural seasonal temperature changes remain nondormant. From October 1981 through June 1983, seeds exhumed at monthly intervals germinated 80 to 100% at all thermo-periods. These results do not support suggestions that seeds of curly dock buried in soil enter dormancy. However, the results do explain why seeds of this species in the Beal and Duvel buried-seed experiments germinated when exhumed at various times during the growing season.

scholarly journals Effect of thinning intensity on understory herbaceous diversity and biomass in mixed coniferous and broad-leaved forests of Changbai Mountain

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Gerong Wang ◽  
Yue Sun ◽  
Mo Zhou ◽  
Naiqian Guan ◽  
Yuwen Wang ◽  
...  
Keyword(s):  
Seasonal Changes ◽  
Mixed Forest ◽  
Growing Season ◽  
Total Biomass ◽  
Herb Layer ◽  
Simpson Index ◽  
Thinning Intensity ◽  
Ground Biomass ◽  
Below Ground ◽  
Understory Herb

Abstract Background Herbs are an important part of the forest ecosystem, and their diversity and biomass can reflect the restoration of vegetation after forest thinning disturbances. Based on the near-mature secondary coniferous and broad-leaved mixed forest in Jilin Province Forestry Experimental Zone, this study analyzed seasonal changes of species diversity and biomass of the understory herb layer after different intensities of thinning. Results The results showed that although the composition of herbaceous species and the ranking of importance values were affected by thinning intensity, they were mainly determined by seasonal changes. Across the entire growing season, the species with the highest importance values in thinning treatments included Carex pilosa, Aegopodium alpestre, Meehania urticifolia, and Filipendula palmata, which dominated the herb layer of the coniferous and broad-leaved mixed forest. The number of species, Margalef index, Shannon-Wiener index and Simpson index all had their highest values in May, and gradually decreased with months. Pielou index was roughly inverted “N” throughout the growing season. Thinning did not increase the species diversity. Thinning can promote the total biomass, above- and below-ground biomass. The number of plants per unit area and coverage were related to the total biomass, above- and below-ground biomass. The average height had a significantly positive correlation with herb biomass in May but not in July. However, it exerted a significantly negative correlation with herb biomass in September. The biomass in the same month increased with increasing thinning intensity. Total herb biomass, above- and below-ground biomass showed positive correlations with Shannon-Winner index, Simpson index and Pielou evenness index in May. Conclusions Thinning mainly changed the light environment in the forest, which would improve the plant diversity and biomass of herb layer in a short time. And different thinning intensity had different effects on the diversity of understory herb layer. The findings provide theoretical basis and reference for reasonable thinning and tending in coniferous and broad-leaved mixed forests.

scholarly journals Seasonality of forest invertebrates in Hong Kong, South China

2002 ◽  
Vol 18 (4) ◽  
pp. 637-644 ◽  
Author(s):  
Kwok Hon Kai ◽  
Richard T. Corlett
Keyword(s):  
Hong Kong ◽  
Seasonal Changes ◽  
Bird Community ◽  
Absolute Minimum ◽  
Northern Margin ◽  
Plant Names ◽  
Bird Fauna ◽  
Summer Temperatures ◽  
Formed Part ◽  
The Tropics

Because of its position on the northern margin of the tropics (22° 17′N) and the southern coast of a huge continent, Hong Kong has a climate in which both temperature and rainfall are highly seasonal. Although summer temperatures are equatorial, the January mean is only 15.8 °C,and the absolute minimum recorded at sea level is 0 °C (Dudgeon & Corlett 1994). As a result, all aspects of the ecology of Hong Kong show seasonal changes. The most dramatic changes occur in the bird fauna, with the majority of species migratory (Carey et al. 2001). The winter fruiting peak in secondary shrublands and the forest understorey coincides with the arrival of partially frugivorous migrant robins and thrushes (Corlett 1993). However, while resident insectivore-frugivores consume almost entirely fruit during this period (Corlett 1998), all the winter visitors continue to eat insects and some (e.g. Phylloscopus warblers) are entirely insectivorous. The study of insect seasonality reported here formed part of a 30-mo study of the seasonality of a forest bird community in Hong Kong (Kwok & Corlett 1999, 2000). Plant names follow Corlett et al. (2000).

scholarly journals A preliminary study of the behaviour of water buffaloes (<i>Bubalus bubalis</i>) imported to Poland (Short Communication)

2012 ◽  
Vol 55 (5) ◽  
pp. 415-419 ◽  
Author(s):  
I. Antkowiak ◽  
J. Pytlewski ◽  
A. Purczyńska ◽  
R. Skrzypek
Keyword(s):  
Short Communication ◽  
Growing Season ◽  
Bubalus Bubalis ◽  
Climatic Conditions ◽  
Drainage Ditch ◽  
Short Period ◽  
Summer Temperatures ◽  
Preliminary Study ◽  
Time Of Year ◽  
Lying Down

Abstract. This study was carried out on 26 adult water (river) buffaloes (25 females and 1 male) imported in 2006 to an eco-tourism farm in the Wielkopolska province, Poland. During the growing season, animals were kept on a logged pasture covering an area of about 15 ha. The pasture was divided into three approximately equal parts, each with a different facility available for wallowing; i.e. pond, drainage ditch and stream. Behavioural observations were carried out three times in July and August 2007 in approximately 14-d intervals, each time during one day on a different part of the pasture, always between 06.00 and 16.00. The method of registration was instantaneous scan sampling, performed at approximately 60 min intervals. On the days of observations mean daily temperature varied from 20.2 to 20.8 °C. Grazing was the behaviour shown by the highest percentage of animals in the herd (58.6%), followed by rumination (28.2%), lying down (26.5%), wallowing (12.9%) and standing (1.4%). When they had access to a pond or ditch, the proportion of animals wallowing was twice as much compared to stream access (P<0.05). It was concluded that the welfare of the investigated buffaloes was not compromised during the high summer temperatures that can be encountered in Poland. Results also indicate that the highest level of welfare can be reached in this time of year when animals are provided with access to ample facility for wallowing. Under our climatic conditions facilities with still or slowly moving water appeared to be preferred by river buffaloes. However, this study has a limitation which is short period of observation, thus it is possible that a longer and more representative period of observations could change these conclusions.

scholarly journals Eastern white pine and eastern hemlock growth: possible tradeoffs in response of canopy trees to climate

2021 ◽  
Author(s):  
Rebecca L. Stern ◽  
Paul Schaberg ◽  
Shelly A Rayback ◽  
Paula F. Murakami ◽  
Christopher Hansen ◽  
...  
Keyword(s):  
Maximum Growth ◽  
Eastern Hemlock ◽  
Competitive Advantages ◽  
White Pine ◽  
Eastern White Pine ◽  
Canopy Trees ◽  
Pollutant Deposition ◽  
Summer Temperatures ◽  
Spring Temperatures ◽  
Over Time

A warming climate and extended growing season may confer competitive advantages to temperate conifers that can photosynthesize across seasons. Whether this potential translates into increased growth is unclear, as is whether pollution could constrain growth. We examined two temperate conifers - eastern white pine (Pinus strobus L.) and eastern hemlock (Tsuga canadensis (L.) Carrière) - and analyzed associations between growth (476 trees in 23 plots) and numerous factors, including climate and pollutant deposition variables. Both species exhibited increasing growth over time and eastern white pine showed greater maximum growth. Higher spring temperatures were associated with greater growth for both species, as were higher autumnal temperatures for eastern hemlock. Negative correlations were observed with previous year (eastern hemlock) and current year (eastern white pine) summer temperatures. Spring and summer moisture availability were positively correlated with growth for eastern white pine throughout its chronology, whereas for hemlock, correlations with moisture shifted from being significant with current year’s growth to previous year’s growth over time. The growth of these temperate conifers might benefit from higher spring (both species) and fall (eastern hemlock) temperatures, though this could be offset by reductions in growth associated with hotter, drier summers.

Persistence and water use efficiency of a tropical grass and lucerne on a solodic soil on the Far North-West Slopes of New South Wales

1993 ◽  
Vol 33 (2) ◽  
pp. 245 ◽  
Author(s):  
PG Tow
Keyword(s):  
Water Use Efficiency ◽  
Water Use ◽  
Dry Matter ◽  
New South ◽  
New South Wales ◽  
North West ◽  
South Wales ◽  
Summer Temperatures ◽  
Spring Temperatures ◽  
Use Efficiency

The persistence and water use efficiency of Digitaria eriantha spp. eriantha and Hunter river lucerne were compared on red solodic soil with a hardsetting surface and poor internal drainage, on the North- West Slopes of New South Wales. After prolonged watering, the profile was wet to a depth of 48 � 1.5 cm, with an available moisture store of 90 mm. Over 3 years, persistence of digitaria was excellent. The population of lucerne was reduced following flooding at summer temperatures, Dry matter production of nitrogen (N) fertilised digitaria per mm warm season rainfall was similar to that of tropical grasses adapted to comparable rainfall environments in subtropical Queensland. Lucerne dry matter per mm rainfall was only about half that of digitaria (3.2 v. 6.3 kg). Lucerne grew well in mixture with digitaria except under prolonged wet soil conditions in summer. Artificial solodic profiles were constructed in the glasshouse to compare digitaria and lucerne in monoculture and mixture under varying temperature, moisture, and N regimes. Lucerne showed sensitivity to both high and low moisture levels at summer temperatures but performed very well at spring temperatures and moderate moisture levels where the mean evapotranspiration ratio was 400 g water per g dry matter. Water use efficiency was higher in digitaria than in lucerne, except at spring temperatures without added N. Water use efficiency of the mixture was always similar to that of the most efficient monoculture of the particular treatment.

Sign in / Sign up

Export Citation Format

Share Document