ONSET OF SEED DORMANCY IN <i>AEGILOPS KOTSCHYI</i> BOISS. AND ITS EXPERIMENTAL MODIFICATION

Wurzburger, Judith; Koller, D.

doi:10.1111/j.1469-8137.1973.tb02082.x

Cited by 22 publications

(4 citation statements)

References 6 publications

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“…A delayed germination in the smaller seeds of several Aegilops has also been observed in natural conditions (i.e. with seeds enclosed in the dispersal unit) and explained by the influences of both maternal and sibling factors, through the presence of an inhibitor in the glumes, internal levels of gibbellerins or competition for essential metabolites among sibling seeds (Lavie et al ., 1974; Wurzburger and Leshem, 1967; Wurzburger and Leshem, 1969; Wurzburger and Koller, 1973; Dyer, 2004). However, the implications of such constrains on the emergence phenology in nature were not well understood.…”

Section: Discussionmentioning

confidence: 99%

Seed heteromorphy influences seed longevity in Aegilops

et al. 2018

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The genus Aegilops belongs to the secondary gene pool of wheat and has great importance for wheat cultivar improvement. As a genus with only annual species, regeneration from seeds in Aegilops is crucial. In several species in Aegilops, spikes produce different seed morphs, both in size and germination patterns. However, little is known about the ecology of seed germination, nor about the seed longevity in this genus. Here we investigated the germination phenology of Ae. neglecta under laboratory and field conditions and assessed longevity of different seed morphs of five additional Aegilops species using controlled ageing tests. Large seeds were short-lived and germinated faster than small seeds in most of the species. Field experiments with Ae. neglecta showed that large seeds of the dimorphic pair germinated 3 months after dispersal in contrast to 14 months for smaller seeds. Differences in longevity were detected not only in dimorphic seed pairs, but also among seeds from different positions on the spike. Our results indicate that different longevities in seed morphs of Aegilops may reflect a different soil seed bank persistence, with smaller seeds able to maintain a higher viability after dispersal than larger ones, thereby spreading seedling emergence over two years. Differences of seed germination and longevities between seed morphs in Aegilops may have important implications for ex situ seed conservation and reinforce the hypothesis of a bet-hedging strategy in the germination ecology of this genus.

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Section: Discussionmentioning

confidence: 99%

Seed heteromorphy influences seed longevity in Aegilops

et al. 2018

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“…An important component controlling the strength of germination inhibition may be the length of time the maternal tissues are biologically active. Wurzburger and Koller (1973) found that the inhibitory effects increased in desert populations of A. kotschyi the longer the seeds were together. This suggests that extended growing seasons should be strongly correlated with the production of chemical inhibitors.…”

Section: Discussionmentioning

confidence: 99%

The seed ecology of Aegilops triuncialis: linking trait variation to growing conditions

Dyer

2017

Seed Sci. Res.

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Adaptive plastic responses in invasive species allow for establishment and persistence despite the lack of genetic matching to new environments. The capacity of annual species to invade habitats to which they are not adapted is likely to be predicated on post-invasion seed trait variation correlated with conditions in the new habitat. To test this, I compared variation in seed traits and germination patterns of Aegilops triuncialis, an invasive annual grass, from 69 sample populations from 24 sites in California (USA) across 13 years. Seed mass, germination fractions, seed viability, and strength of induced dormancy between dimorphic seed pairs were used to investigate plastic variation within and among populations, across two general soil types, and among two widespread maternal genotypes. I found that seed mass variation was constrained although both seed types showed a 3-fold range among populations, 20–25% variation within populations between years, and was positively correlated with longer growing seasons. However, induced seed dormancy in the small seed type was correlated with large seed mass and to late-season precipitation, suggesting that longer growing seasons influence the strength of maternal and sibling chemical signals that induce dormancy in the small seeds. Thus variation in small seed germination fractions varies with the growing conditions experienced by the maternal plant. The greater longevity of the small seed type suggests that plasticity in germination in this species may contribute to seed bank formation, which is atypical of invasive annual grasses in California, and this may contribute to the persistence and spread of A. triuncialis in invaded ranges.

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“…Fandrich and Mallory-Smith (2005) found that caryopses positioned in the secondary florets usually germinate first. Wurzburger and Koller (1973) found that drying improved germinability of the primary caryopses in desert goatgrass but only during the phase of increasing germinability. The response observed occurred soon after the end of the increasing germinability phase for all spike sections.…”

Section: Resultsmentioning

confidence: 94%

Determining Physiological Maturation of Jointed Goatgrass (Aegilops cylindricaHost) Caryopses

2006

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Information on jointed goatgrass caryopsis development is currently lacking in published literature. It is hoped that through a better understanding of jointed goatgrass caryopsis ontogeny more effective weed-management strategies will be developed. Greenhouse experiments were initiated in fall 2002 and 2003 and completed the following spring seasons. Jointed goatgrass plants were started from spikelets, vernalized for 8 wk at 4 C, and grown in a greenhouse. Treatments were the number of days after anthesis (DAA) that a spike was allowed to remain on the plant before harvesting and ranged from 2 to 34 DAA, in increments of 1 (2002) or 2 (2003) d. Individual spikes were divided at harvest into three sections: top, middle, and bottom, disarticulated from the rachis, placed into a germinator, and germination recorded each day. Goatgrass spikelets germinated as early as 2 DAA, although spikelets harvested <7 DAA had <3% germination for all spike sections and were extremely variable, especially for the middle and bottom sections. Time to germination was similar for all sections of the spike. Maximum average germination of the top section was 72% compared with 86% for the bottom and middle sections. Our data suggest that factors other than developmental rate (i.e., dormancy) may affect germination in sections of the spike. A second year of the experiment was conducted for validation. Model validation suggested that although trends were similar in both years, variation in germination response might be too great for accurate, predictive model construction. The early germination shown in this research demonstrates that control measures must be implemented earlier than previously prescribed to prevent jointed goatgrass reproduction.

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ONSET OF SEED DORMANCY IN AEGILOPS KOTSCHYI BOISS. AND ITS EXPERIMENTAL MODIFICATION

Cited by 22 publications

References 6 publications

Seed heteromorphy influences seed longevity in Aegilops

Seed heteromorphy influences seed longevity in Aegilops

The seed ecology of Aegilops triuncialis: linking trait variation to growing conditions

Determining Physiological Maturation of Jointed Goatgrass (Aegilops cylindricaHost) Caryopses

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