Beech Seeds Research Articles

Effects of snow accumulation on survival of beech (Fagus crenata) seed

The escape of beech seeds from seed predators and winter desiccation due to snow accumulation was studied by comparing two sites in Japan: one site that experiences much snow and another site that experiences less snow cover. At the site with greater snow cover, about 70% of the beech seeds escaped seed predation by rodents during winter and about 70% of surviving seeds germinated successfully in spring. At the site with less snow cover, however, all of the beech seeds were eaten by rodents, and all seeds that were protected from feeding were killed by winter desiccation. We confirmed that snow prevents beech seeds from predation by rodents because it conceals their sight and scent. These effects are one of the main reasons why beeches in snowy areas regenerate constantly and those in less snowy areas do not.

Desiccation-tolerance of Fagus crenata Blume Seeds from Localities of Different Snowfall Regime in Central Japan

In beech (Fagus crenata Blume) forests on the Pacific Ocean side in Central Japan, snowpack depth is little and xeric conditions may prevail in winter, in contrast to heavy snow in beech forests on the Japan Sea side. The effects of such conditions during winter on the viability of beech seeds were studied at a beech forest on the Pacific Ocean side. Thickness and weight ratio of pericarp of beech seeds were significantly greater in populations on the Pacific Ocean side compared to the Japan Sea side, this apparently being related to snowpack depth in winter. During the initial stage of seed drying, the drying rate of seeds from the Fuji population (the Pacific Ocean side) was less than that from the Sumon population (the Japan Sea side), possibly due to the thicker pericarp. Germination percentage of seeds which dried to a water content as low as 7% d.w. did not decrease for either population, indicating desiccation tolerance of beech seeds. In the beech forest (University Forest at Yamanaka) on the Pacific Ocean side, water content of seeds sown below litter from both populations remained sufficient for viability during winter. Germinating seeds from the populations on the Japan Sea side were more desiccation-sensitive in early spring, compared to those from the Fuji population, partially due possibly to differences in pericarp thickness.

Quantification of GA1, GA3, GA4, GA7, GA8, GA9, GA19 and GA20 ; and GA20 metabolism in dormant and non-dormant beechnuts

The endogenous levels of GA1, GA3, GA4, GA7, GA8, GA9, GA19 and GA20 were determined in beech seeds (Fagus sylvatica L.) treated with different dormancy breaking treatments. Gibberellins were analysed separately in cotyledons and embryo axes. After purification of the extracts, GAs were quantified by GC-MS-selected ion monitoring (GC-MS-SIM) with deuterated GAs as internal standards. The results showed that GAs corresponding to the 13-OH pathway seemed to be involved in dormancy breaking. Strong differences in GA1, GA3, GA8, GA19 and GA20 levels between embryo axes and cotyledons of dormant and non-dormant beechnuts were detected with less pronounced differences for GA4, GA7 and GA9 levels. Both the quantitative differences between dormant and non-dormant seeds in the analysed GAs corresponding to the 13-OH pathway, and the capacity of non-dormant seeds to carry out metabolic conversions when labelled GA20 was injected into the seeds, reveal a dynamic role of GAs in dormancy release.

Micropropagation ofFagus sylvatica L.

An in vitro shoot multiplication system was established from juvenileFagus sylvatica L. tissues, and plantlets were regenerated. Embryonic axes were excised from beech seeds and germinated in vitro on media supplemented with 6-benzyladenine (BA) to obtain plantlets with axillary shoots. Shoot multiplication was maintained by sequential subculture of axillary shoot tips and basal segments on Woody Plant Medium supplemented with 0.5 mg/liter BA+2 mg/liter zeatin+0.2 mg/liter naphthaleneacetic acid (NAA). The effeciency of shoot multiplication clearly depended on the kind of explant used. Transfer to fresh medium every 2 wk during the 6-wk multiplication cycle improved multiplication rates. In the rooting stage, an initial 7-day dark period significantly improved rooting capacity and accelerated the emergence of roots on auxin-treated shoots. Adventitious buds were induced on the intact hypocotyls of the whole plantlets derived from the initial embryonic axis explants, especially on those cultured on medium with 1 mg/liter BA. Cotyledon and hypocotyl segments isolated from seedlings grown in vitro from embryos also exhibited capacity for adventitious bud formation, especially when cultured on media supplemented with 0.5 mg/liter BA + 0.1 mg/liter NAA.

Composition of Lipids of Beech (Fagus sylvatica L.) Seed Oil

The lipid composition of beech (Fagus sylvatica) seeds is reported in the present study. Triacylglycerols (94.8% ) were found to be the major component in the oil followed by sterols (0.9% ) diacylglycerols (0.8% ), phospholipids (0.7% ), free fatty acids (0.5% ) and monoacylglycerols (0.3% ) in minor quantities. The composition of molecular species of triacylglycerols was analyzed by GC on the basis of chain length and C-57 was found to be the major species followed by C-55, C-59, C-53 and C-61. The sterol fraction constituted β-sitosterol and stigmasterol with 89.3 and 10.7% respectively. Phosphatidylinositol and phosphatidylethanolamine were the two phospholipids with 55 and 45% present in the phospholipid fraction of the beech seed oil. Oleic, linoleic and palmitic acids were found to be the major fatty acids in all the acyl lipid classes with small variations in quantities.

Seed Predation and Cross‐Pollination in Mast‐Seeding Beech (Fagus Sylvatica) Patches

In this study we examined cross—pollination and levels of insect and vertebrate predation on the seeds of beech as a function of stand size and tree size. Cross—pollination in this wind—pollinated species is positively correlated with stand size and flower density. In two mast years, 6—14% of seeds contained no kernels, and in a nonmast year the figure was 24%. Predispersal destruction of seeds by a moth (Cydia fagiglandana) was 3.1% in a mast year and 38% in a nonmast year. The variation in seed destruction by vertebrates was much less between mast (5.7%) and nonmast (12%) years. Destruction by the moth was negatively correlated with tree size, while that by vertebrates was positively correlated with tree size. Vertebrate seed predation was negatively correlated with stand size. In a large stand, <10% of the seeds were consumed by vertebrates by April in two mast years. Both cross—pollination and seed predation may have been important factors in the evolution of mast seeding in beech.

SEED DENSITY, COVER, PREDATION AND THE DISTRIBUTION OF BIRDS IN A BEECH WOOD IN SOUTHERN SWEDEN

SUMMARYThe distribution of six species of birds within a beech wood was analysed in two winters when beech seeds were abundant. All species were concentrated in patches where seed density was high in one winter, but only two showed a similar distribution in the second winter. The distribution of the other four species, three tits Parus spp. and the Nuthatch Sitta europaea, was positively correlated with low cover. Cover was inversely correlated with seed density. Bird predators were recorded many times during the second winter but not at all during the first winter. It is suggested that predator avoidance was more important than food density for some species in the second winter.The relationships between bird density and both food and cover were sigmoid in shape.The proportion of the seed crop consumed by the birds was estimated at about 4.5%, which was probably more than the amount consumed by mammals. The Woodpigeon Columba palumbus (which took 44% of the total seeds consumed by birds) and the Brambling Fringilla montifringilla (33%) were the most important seed consumers among the birds.

Beech Seeds as an Ecosystem Component

consumption of 0.7-5.4 g m-2 yr'l (21-154 kJ mn2 yr-1) or 8-61% of the annual endosperm production (average about 36%). Natural reproduction was definitely unsuccessful. The potential food resource (endosperms) for granivorous heterotrophs in the forest floor represented 1-34 g m-2 yr-1 (30-961 kJ m-2 yr-1), however, apparently postdispersal seed predation was extremely low. In 1974 about 5 % of the seed production were utilized in predispersal seed predation, whereas 90-95% entered the detritus pathway; the importance of the latter channel in the flow pattern of seed borne energy and the effect of predispersal seed predation in the research site are emphasized.

A Study of a Wood Mouse Population in Wytham Woods, Berkshire

The wood mouse, Apodemus sylvaticus, is common throughout the British Isles and Europe and eastward into Asia (Matthews, 1952). Ecologically it is one of the most adaptable and important of the European small mammals but, like most common species, it has attracted very little attention from ecologists. The wood mouse has been studied far less than its American counterpart, Peromyscus maniculatus , although detailed comparisons between the two would be extremely valuable as a guide to the nature of the population dynamics and community relationships of small mammals. This study was done in a five-acre copse known as “The Pasticks,” 4½ miles northwest of Oxford in Wytham Woods, Berkshire. The Pasticks is a mixed-wood copse; it is surrounded by arable fields and was chosen for its relative isolation from adjacent woodlands. The dominant vegetation of the copse is an oak-ash-sycamore association ( Quercus robur — Fraxinus excelsior — Acer pseudo-pUtanus ) modified by plantings of elm ( Ulmus campestris ), birch ( Betula alba ), beech ( Fagus sylvatica ) and sweet chestnut ( Castanea sativa ). A long history of natural development without management has allowed the formation of a relatively primitive woodland. The dense canopy and deep shade of this woods is reflected in the simplicity of the shrub and field layers of vegetation. Hazel ( Corylus avellana ) and elder ( Sambucus nigra ) occur scattered through the woods and the field layer is composed almost entirely of Dog's Mercury ( Mercurialis perennis ) and nettle ( Urtica dioica ). The edge of the copse is bordered by an unkept hawthorne hedge ( Crataegus oxyacanthoides ) which has grown to heights of 10 and 12 feet in places. Most of the seed foods produced in the Pasticks are palatable to wood mice (Miller, 1954) and 1950 seemed to be an exceptionally good year for seed production. The seeds of oak, beech and chestnut seemed to be selected …