The influence of seed size and depth of sowing on pre-emergence and early vegetative growth of subterranean clover (Trifolium subterraneum L.)

Abstract

Changes in the pre-emergence distribution of dry matter in subterranean clover (Trifolium subterraneum L.) variety Bacchus Marsh were followed at 21°C, using three sizes of seed and three depths of sowing, ½, 1¼, and 2 in. Decreasing seed size and increasing depth of sowing both reduce the weight of the cotyledons a t emergence. Seed of the three sizes were sown a t three depths in pot culture a t staggered intervals so that emergence was simultaneous. Dry weight in the early vegetative stage was proportional to seed size, and total leaf area and leaf numbers showed similar trends. Plants of each seed size grew at the same relative rate. No effect of depth of sowing could be detected, and this was shown to be due to the cotyledon area a t emergence being constant for any given seed size, regardless of varying depth of sowing and hence of cotyledon weight. It was concluded that seed size in a plant having epigeal germination and without endosperm is of importance: firstly, in limiting the maximum hypocotyl elongation and hence depth of sowing, and secondly, in determining cotyledon area. Cotyledon area in turn influences seedling growth, which is not affected by cotyledon weight. Once emergence has taken place, cotyledonary reserves are of no further significance in the growth of the plants.

Cryptic Consequences of a Dispersal Mutualism: Seed Burial, Elaiosome Removal, and Seed-Bank Dynamics

“…Moreover, because rodents also use elaiosomes as cues for locating seeds, elaiosome removal can reduce seed predation levels on the soil surface (Slingsby and Bond 1985) and below ground (Heithaus 1981). In contrast, seeds buried below some critical depth may fail to emerge (Wesson andWareing 1967, Guo et al 2001), emerge later in the season (Black 1956), or have fewer reserves remaining after emergence (Seiwa et al 2002).…”

Planting depth effects on overdrilled seedling survival in summer

“…Numerous investigations of planting depth effects (to date confined to tilled seedbeds) have extrapolated from seedling emergence responses to later plant densities (Williams 1922;Black 1955Black , 1956McKee & Peiffer 1973) but little attention has been paid to possible planting depth effects on survival of seedlings after emergence and the implication of these for plant densities. Planting depth studies (in either tilled or untilled seedbeds) which aim to make recommendations on optimum planting depths must consider both effects, especially because early growth responses to planting depth, which might modify initial seedling density responses by affecting survival, are documented.…”

Analysis of the variability of sugar beet (Beta vulgaris L) growth during the early stages. I. Influence of various conditions on crop establishment

“…Models for later growth are no longer based on an exponential function and specifically take into account the increase in LAI and incident light interception (Milford et al, 1985b;Day, 1986 (Carver, 1977), maize (Abd El Rahman and Bourdu, 1986), vegetables (Austin and Longden, 1967;Benjamin, 1984Benjamin, , 1987 and clover (Black, 1956(Black, , 1957 (Duval and Boiffin, 1990 (Greenwood et al, 1977;de Wit et al, 1979).…”