Buried Seeds Research Articles

The Occurrence of Buried Viable Seeds in Relation to Environmental Gradients

The available information on buried seeds is briefly reviewed. Density of buried viable seeds is found to decline with increasing altitude, latitude and successional age and with decreasing intensity of disturbance. Maximum densities of buried seeds are probably to be found in temperate arable situations. Minimum densities occur in tropical rain forest and in arctic and alpine habitats. These patterns can be satisfactorily explained in terms of gradients of stress and disturbance, where stress is a function of the external constraints limiting the rate of dry matter production, and disturbance is the total or partial destruction of the vegetation. Buried seed density is correlated positively with disturbance and negatively with stress.

A review of the significance of buried legume seeds with particular reference to New Zealand agriculture

Abstract Studies of buried legume seed populations in temperate grassland are reviewed, including the origin and dissemination of buried seeds, techniques of extraction from soil samples, and quantities of seeds found in pasture soils, with emphasis on New Zealand. The effects of management practices on levels of buried legume seeds are discussed and the problem of buried seeds in legume seed production crops is considered with reference to current seed certification rules.

I. Buried seed populations

Abstract Numbers of buried legume seeds in the upper layers of soil were determined in a survey over an area of hill country pasture at the Grasslands Division research station, Ballantrae. Seeds of suckling clover (Trifolium dubium L.) and white clover (T. repens L.) were most numerous, mean numbers per m2 being average for this particular type of pasture (2541 and 291 repectively). White clover seed numbers were not significantly different between site types, whereas suckling clover seeds were highest on north aspects and stockcamps and lowest on south aspects and wet sites. These variations could be attributed largely to climatic and stock behaviour factors, and distribution of legume plants. Little of the buried legume seed germinated in tests, but scarification revealed that viability was high. The role of buried legume seed as a source of seed in pasture improvement is discussed.

Seed Detection by the Wood Mouse Apodemus sylvaticus

In laboratory experiments, there was no significant difference between the number of buried seeds of eight species which were either detected or removed, in total darkness and subdued light, by wood mice Apodemus sylvaticus L. The percentage detection of tree seeds and peas correlated positively with the weight of the seeds and was significantly higher than that of cereal grains and empty control dishes. When the seeds were coated with vegetable oil, containing 47.4% linoleic acid, both their detection and palatability increased considerably. It is suggested that wood mice use certain olfactory stimuli to detect buried seeds.

A STUDY OF THE POPULATION DENSITY, LONGEVITY AND GERMINATION OF BURIED SEED IN SELECTED SITES IN THE MANAWATU

A study of the population density and the viability of buried seeds was determined in soil from six sheep pastures of varying ages; on two soil types, clay and sand, and at two depths (0 to 7.5 cm and 7.5 to 15 cm).

Effect of Burning on Regeneration from Seeds in Wet Sclerophyll Forest

SUMMARY The importance of dormant buried seeds of understorey species of the wet sclerophyll forests of northern N.S.W. is discussed in relation to their germination ability following fire or mechanical or chemical abrasion. The optimum temperatures for germination were determined for the more common species. The intensity and frequency of burning was shown to affect the species composition of the regeneration very significantly.

Buried seed populations in the subarctic forest east of Great Slave Lake, Northwest Territories

Buried seeds were studied in the subarctic forest east of Great Slave Lake, N.W.T., where 62 surface samples were collected in upland vegetation of different ages and compositions. No seeds germinated from any of the samples after cold treatment and exposure to warm, moist environment. Seeds were present in the soil, but most of them proved non-viable by the tetrazolium chloride test.Lack of viable buried seeds is consistent with a poleward decrease in the buried viable seed populations under forests. Possibly the gradient parallels a decrease in length of growing season and its effect on germination strategies. The lack of viable buried seeds provides a partial explanation of observed slow vegetational recovery after fire in subarctic forests.

The Allelopathic Influences of Sassafras albidum in Old‐field Succession in Tennessee

Allelopathy seems to be the mechanism that allows Sassafras albidum to maintain itself in relatively pure stands through many stages of old—field succession. Field studies revealed that 10 species consistently occurred exclusively outside of clump canopies and 7 other species predominated beneath the sassafras canopy. We suggest that annual herbs are being effectively excluded from the understory flora. 2—pinene, α—phellandrene, eugenol, safrole, citral, and d—camphor were isolated were within and outside of sassafras stands from leaves, litter, soil, and roots. Germinating seeds watered with aqueous leachates of leaves, litter, and canopy washings showed varying degrees of radicle reduction during germination. Germination on soil discs from beneath sassafras stands was significantly lower in four of the test species; in seeds overwintered in sassafras litter it was significantly lower in all species. There was a positive correlation between α—phellandrene concentration and reduction in radicle growth in Acer negundo and Ulmus americana. Sufficient incoming and buried seeds were available to support a richer and more abundant understory flora than was found in the vegetational survey. The different modes of sassafras for releasing phytotoxins into the environment at different times of the year operate to continually influence its surroundings.

The Role of Pin Cherry (Prunus pensylvanica L.) in the Maintenance of Stability in Northern Hardwood Ecosystems

The design of the life cycle of pin cherry (Prunus pensylvanica L.), a successional species common on disturbed sites throughout much of the northern hardwood and boreal forest ecosystems, assures that its occurrence is integrated into the pattern of disturbance in the climax ecosystem. The combination of buried seed strategy and the mobility offered through avian consumption of fruits ensures reasonably large populations of buried, viable seeds in the soils of forests well after the disappearance of pin cherry from a particular site. Soil sampling data indicate that sufficient numbers of viable pin cherry seeds reside in the soils of second—growth forests in central New Hampshire to account for the dense stands frequently observed after cutting or burning. Further, germination of these buried seeds is apparently triggered by some factor(s) associated with formation of a large gap. By age 25 or 30, when pin cherry individuals are dying rapidly, sufficient numbers of seeds have been produced and disseminated in a dormant condition for the cycle to renew itself with the subsequent occurrence of major disturbance. In high density stands pin cherry grows rapidly, with early attainment of canopy closure (high leaf area index), and rapid attainment of high values of net annual production and nutrient accumulation.

Hormonal Control of Weed Seed Germination

Freshly-harvested seeds of several common weeds showed little or no promotion of germination by light. However, after burial for 6 months, germination becomes entirely dependent on exposure to light. Red light promoted the germination of the buried seeds, and this promotion was reversed by far-red light, indicating phytochrome involvement. Freshly-harvested seeds were made light-requiring by treatment with mannitol. The germination of these light-requiring seeds was promoted by red light, gibberellic acid (GA), acetylcholine (ACh), and adenosine 3′,5′-monophosphate (cyclic AMP). The phytochrome response may trigger ACh synthesis which causes the release of GA from a bound form and/or GA synthesis which enhances the production of cyclic AMP which initiates the germination response.

Ecology of germination of weed seeds : I. Role of temperature and depth of burial in soil.

Merremia gangetia Linn. (Cuf) is one of the most important weeds invading cultivated lands of India. Temperature, both high (45° C) and low (15° C) exhibit a definite role in development of the weed, particularly during germination. Higher tempeeratures (45° C) during dry storage appeared to be the main factor in laboratory experiments as well as in nature. Low temperature induced secondary dormancy and its removal by incubation at 35° C helps to explain the ecological mechanism through which the weed endures winter conditions. Germination of buried seeds confirm that the atmospheric conditions were found to be more effective in upper layers of soil. Ecological adaptations of this weed via germination requirements are assessed in the paper.

Seed Preference and Buried Seed Retrieval of Dipodomys deserti

Journal Article Seed Preference and Buried Seed Retrieval of Dipodomys deserti Get access Robert B. Lockard, Robert B. Lockard Department of Psychology and Department of Neurological Surgery, University of Washington, Seattle, 98105 Search for other works by this author on: Oxford Academic Google Scholar Joan S. Lockard Joan S. Lockard Department of Psychology and Department of Neurological Surgery, University of Washington, Seattle, 98105 Search for other works by this author on: Oxford Academic Google Scholar Journal of Mammalogy, Volume 52, Issue 1, 26 February 1971, Pages 219–221, https://doi.org/10.2307/1378454 Published: 26 February 1971 Article history Accepted: 10 August 1970 Published: 26 February 1971

A Body Capacitor-Olfactometer for Squirrels and Rats

The body capacitor-olfactometer described herein was developed for the purpose of measuring quantitatively the number and duration of odor seeking (primarily food seeking) responses of wild ground squirrels (Spermophilus spp.) and rats (Rattus spp.) to various olfactory cues presented free of the in- fluence of taste, without the reward of food, and without requiring that these field-caught rodents first be trained to the olfactometer before their responses could be monitored. Species of rodents that weigh less than 250 grams possess a body capacitance too low to activate the sensor units, but there is no upper size limit. We believe that this olfactometer could be adapted for mouse-size rodents if ultrasonic, infrared, or some other type of sensor was employed in place of the body capacitor. Field experience has shown that many rodents are macrosmatic, having the ability to locate and remove single seeds of many kinds of crops regardless of whether man has buried them by hand or mechanically. Also, many rodents often naturally bury seeds for later relocation and consumption. Other ex- periments (Howard and Cole, 1967; Howard et al., 1968) have shown that deer mice (Peromyscus maniculatus), and presumably many other rodents, have no difficulty utilizing olfactory cues to locate buried seeds of conifers and cereals. In our ecobehavioral studies of wild rodents it usually is necessary to examine many field-caught animals for brief periods of time rather than sub- ject a small number of suitably conditioned individuals to repeated tests as is commonly done in psychobiology. The olfactometer described herein was developed to record the number and duration of a subject's response to from one to three odors being emitted simultaneously from nine stations in the olfactometer arena; it does not measure the olfactory thresholds of animals or the quantity of the test volatiles that are present. Instead, it monitors the frequency of searching responses and the duration of each visit an animal makes to an odor station in its search (digging) for the source of the intro- duced odors. Only one animal is placed in the olfactometer at a time. The change in response time animals make to the test odors following conditioning experiments, such as creation of bait shyness, also can be measured with the olfactometer. All experimental odors are presented in sufficient quantity to be readily detected by the test animal throughout the arena of the olfac- tometer. We have not attempted to determine the parameters of odor con- centrations that will work in this instrument; we merely make certain that sufficient but constant amounts of odor of each test substance is present so as to be readily detected by the subjects when they are in the arena.

The Role of Light in the Germination of Naturally Occurring Populations of Buried Weed Seeds

Large populations of viable buried arable weed seeds have been found in soil which has been continuously used as pasture for the last six years. Small numbers of dicotyledonous seedlings were found to germinate within the grass sward, but did not appear to become established. A disturbance of this soil, as caused by cultivation, resulted in a large flush of germination during the subsequent 4 weeks. Under laboratory conditions only 10 per cent of these seedlings emerged in the absence of illumination. Under field conditions there was no germination at all in the dark. A short ‘light-break’ of only 90 sec was sufficient to cause the germination of a large proportion of seeds. On the basis of these results it is concluded that the appearance of all weed seedlings from buried seeds, following cultivation, is dependent upon the exposure of these seeds to light.

The growth of barley grass (Hordeum leporinum) in annual pasture. 1. Germination and establishment in comparison with other annual pasture species

Several experiments were carried out to examine aspects of the germination and establishment of seeds of barley grass (Hordeum leprinum), and several of its companions in annual pastures. These indicated that freshly-matured seed of barley grass had considerable dormancy the first summer. While day temperatures remained high it did not germinate readily, but had no marked advantage over its companions. Compared with Wimmera ryegrass (Lolium rigidum), the seeds and seedlings were much larger and it geminated and established mere successfully cr. compact surfaces. Plants arising from surface-sown seeds were compared with those from buried seeds : with barley grass they were much larger, but with Wimmera ryegrass they were not.

Light Requirements of Buried Seeds

IT is well known that the upper layers of many types of soil contain large populations of buried, dormant seeds estimated to amount to many thousands per acre in some instances1. Many of these buried seeds are viable and germinate readily when the soil is cultivated or disturbed in other ways. There is good evidence that such seeds can remain dormant in the soil for long periods; indeed, evidence has recently been presented that seeds which have lain in the soil for as much as 1,700 years are still viable2.

THE EFFECT OF BURNING OF NATIVE PASTURE ON SOIL TEMPERATURE IN NORTHERN NEW SOUTH WALES

Thermocouples were used to measure temperatures at shallow depths (top 39 mm) in soils during late winter burning of hayed‐off native pasture. Different intensities of burning were investigated. The maximum temperature recorded for any treatment was 75–5°C, at 1 mm below the soil surface, and marked temperature rises were recorded only in the upper 10 mm of the soil. The results suggest that the temperature rise induced by burning would have little direct effect on soil organic matter, the microbial populations, or buried seeds. The possible significance of these results in practice is discussed.

EMERGENCE OF EUCALYPTUS REGNANS SEEDLINGS FROM BURIED SEED

SUMMARY Seed of Eucalyptus regnans F. Muell. was sown at various depths in crumby and in highly compacted soils. The numbers of seedlings which emerged per cent of sound seeds sown in crumby soil were: on the surface—16%; at 1/4 inch depth—51%; at 1/2 inch—18%; at 1 inch—2%; and at 2 and 4 inches—0%. Emergence through compacted soil was 1% from 1/4 inch and 0% from greater depths. Most of the buried seeds which failed to germinate died within 14 months. There was no evidence of seedlings having germinated and died before emerging. In the laboratory 70–80% of hypocotyls arising from seeds incubated in the dark at 65°F for 4–6 weeks grew a little over 1 inch tall. A few of the larger seeds produced seedlings a little over 2 in. tall.

THE EIGHTY‐YEAR PERIOD FOR DR. BEAL'S SEED VIABILITY EXPERIMENT

Darlington, H. T., and G. P. Steinbauer. (Michigan State U., East Lansing.) The eighty‐year period for Dr. Beal's seed viability experiment. Amer. Jour. Bot. 48 (4): 321–325. 1961.—Seeds of 20 species of plants were buried 80 years ago on the Michigan State University campus. Bottles have been dug up periodically in the intervening years and the seeds tested for viability. A bottle representing the 80‐year period of burial was dug up this spring and the contents distributed uniformly on the surface of sterilized soil in the greenhouse. Of the 20 species whose seeds were buried in 1879, only 3 have survivors as viable seeds. These are the same 3 that had survived the 70‐year burial period, namely: curled dock, Rumex crispus; evening primrose, Oenothera biennis; and moth mullein, Verbascum blattaria. The low percentage survival of curled dock (2%) indicates that the longevity of the buried seeds of this species is nearing the end. The situation is more favorable for evening primrose, with 10% survival. The third, moth mullein, has about as many survivors as 10 years ago, a remarkably high figure of 70% viability. Since there has been no significant drop in viability of the buried seeds over the last 30 years, it seems highly probable that longevity of buried seeds of this species may extend over a century. A brief summary is given of the current status of the behavior of buried seeds, based on this and other buried seed experiments.

Changes of Wewd Communities by Methods of Cultivation in Winter Cropping on Drained Paddy Fields : (3) Influence of methods of spring and autumn tillage on the structure of weed community and the quantity of weeds with special reference to the analysis of the quantity of weeds by the distributioh in soil of Alopeculus aequalis Sobol. seeds

Combinating each of three tillage methods, shallow tillage by power tiller, deep tillage by power tiller and deep plowing, in spring and autumn, nine plots were laid in 1957. After weeds had ripened and scattered seeds, spring tillage was practiced in the middle of June and then lowland rice was planted, and after its harvest autumn tillage was made in the middle of November. In each plot, the vertical distribution of viable buried seeds of Alopeculus aequalis was surveyed before and after tillage times and at drainage time and number of weeds emerged during the period from autumn to the next spring was counted. Before spring tillage, most of Alopeculus aequalis seeds were placed in the top layer, and this distribution of seeds was changed by the tillage as shown in Fig. 1. The changes in the distribution differed with the three tillage methods. Many viable buried seeds emerged or sprouted under soil to die during the period from drainage to autumn tillage. And number of the viable seeds was reduced by so much in upper layer of soil than in lower (Fig. 3). Accordingly, the distribution was changed as shown in Fig. 4. In the plot of spring shallow tillage, where many seeds were placed in upper layer, total number of seeds within all soil layers was less at the time of autumn tillage than in others. These patterns of the distribution were changed by autumn tillage as shown in Fig. 2. Number of seedlings of Alpeculus aequalis was proportional to number of seeds in the upper emergenable layer (0∼4 cm) (Fig. 5). Consequently, number of seedlings (Table 1) was reduced in the plots combinated deep plowing-shallow tillage, shallow tillage-shallow tillage, and deep plowing-deep tillage, and increased in deep tillage-deep plowing and deep tillage-deep tillage. Moreover, it was shown that deep plowing in spring and shallow tillage in autumn had a tendency to reduce the number of seedlings. Number of seedlings of Stellaria uliginosa was few in the plots deep plowed in either spring or autumn. This fact seems to be very reasonable, based on that few decrease in viable buried seeds took place during the time from the drainage to autumn tillage. The other kinds of weeds hardly emerged. As the result, the structure of weed community differed in each plot as shown in Fig. 6, that is in the plots of autumn deep plowing the proportion of Alopeculus aequalis was high and in the plots of autumn shallow tillage the proportion of Stellaria uliginosa was high.