Seed Water Content and the Vulnerability of Buried Seeds to Foraging Rodents

1993 ◽  
Vol 129 (2) ◽  
pp. 272 ◽  
Author(s):  
Stephen B. Vander Wall
2021 ◽  
Vol 48 (1) ◽  
pp. 28
Author(s):  
Cristian Malavert ◽  
Diego Batlla ◽  
Roberto L. Benech-Arnold

Seedling emergence in the field is strongly related to the dynamics of dormancy release and induction of the seed bank, which is mainly regulated by soil temperature. However, there is limited information on how temperature-driven effects on dormancy changes are modulated by the seed hydration-level. We investigated the effect of seed water content (SWC) on the dormancy release and dormancy induction in Polygonum aviculare L. seeds. We characterised quantitatively the interaction between seed water content (SWC) and temperature through the measurement of changes in the lower limit temperature for seed germination (Tl) during dormancy changes for seeds with different SWC. These relationships were inserted in existing population-based threshold models and were run against field obtained data. The model considering SWC was able to predict P. aviculare field emergence patterns. However, failure to consider SWC led to overestimations in the emergence size and timing. Our results show that in humid temperate habitats, the occurrence of eventual water shortages during late-winter or spring (i.e. short periods of water content below 31% SWC) can affect soil temperature effects on seed dormancy, and might lead reductions in the emergence size rather than to significant temporal displacements in the emergence window. In conclusion, SWC plays an important role for the perception of temperature signals that drive dormancy changes in buried seeds.


Botany ◽  
2009 ◽  
Vol 87 (1) ◽  
pp. 88-96 ◽  
Author(s):  
Pedro E. Gundel ◽  
M. Alejandra Martínez-Ghersa ◽  
Lucas A. Garibaldi ◽  
Claudio M. Ghersa

Neotyphodium endophyte fungi are vertically transmitted symbionts of cool-season grasses. The seed phase of the grass’ life cycle appears to be critical for the persistence of the fungus. Endophyte viability decreases faster than seed viability, but little is known of the effects of this endophyte on seed viability. The endophyte could affect seed viability through changes in water content. Here, we assessed the effects of the endophyte on seed viability, the differential survival of endophyte and seed, and the effects of infection on seed water content. Viability of endophyte-infected and noninfected seeds and endophyte were evaluated over a period of 729 d under 12 controlled environmental conditions. Seed viability was reduced by the infection at high temperature and high relative humidity, but not under other conditions. Moreover, endophyte viability decreased faster than seed viability only under high humidity or high temperature. Seed water content was not affected by endophyte presence. The proportion of viable infected seeds was mainly affected by the loss in endophyte viability and secondly by the differential survival of infected and noninfected seeds. Knowledge on the relative importance of these processes is critical to understand the factors affecting the efficiency of endophyte vertical transmission and the frequency of endophyte-infected plants.


2005 ◽  
Vol 143 (2-3) ◽  
pp. 183-192 ◽  
Author(s):  
F. COSTE ◽  
M. P. RAVENEAU ◽  
Y. CROZAT

A non-destructive indicator of seed water content could significantly help crop scientists with assessment of the effects of environmental conditions during drying on grain qualities or on seed physiological quality. This is particularly important for grain legumes which simultaneously bear pods of different ages. Visual assessment of pod colour has so far been used to date grain legume stages, but now colour can be easily and accurately measured with a portable spectrophotometer. Relationships between the spectrophotometer measurements and the pod and seed water contents were tested in various climatic contexts (3 years: 2000, 2001, 2002; field or greenhouse, two or three sowing dates) for two bean cultivars (Booster and Calypso) and also for one pea cultivar (Baccara) in 2003 near Angers, France. Among the different spectrophotometer measurements, hue angle (h) clearly shows the transition from green (h=180 °) to yellow (h=90 °) and then to red (h=0 °). In each context, h and seed water content (SWC) relationships showed the same pattern of three linear phases: first a steady state; then a sharp decrease from green (h=106–108 °) to yellow (h=85–93 °) just before the end of the seed filling stage for Booster or between the end of the seed filling phase and the beginning of seed drying for Calypso and pea; finally, a slow decrease from yellow to ochre (h=75–78 °) during seed drying. For each bean cultivar, the parameters of the linear relationships showed no differences between maturation conditions. Therefore, 6 h classes matching six SWC classes could be defined over a wide range of SWC between 0·56 and 0·2 g/g for Booster. However for Calypso and pea, only 3 h classes could be defined because of the tight relationships between h and SWC during the end of seed drying, which can be explained by pod walls drying faster than seeds. Hence, spectrophotometer measurements, if calibrated for a given cultivar of a species, could now be used to select pods with seeds of the same water content and therefore to study environmental effects on quality criteria either in controlled conditions or in the field.


Botany ◽  
2012 ◽  
Vol 90 (8) ◽  
pp. 731-742 ◽  
Author(s):  
Félix Pérez-García ◽  
Federico Varela ◽  
M. Elena González-Benito

Gentiana lutea L. (yellow gentian, Gentianaceae) is an important medicinal plant under protection as endangered species in most European countries. The aim of this work was to evaluate variation in seed mass, seed water content, and seed germination among 56 wild accessions of G. lutea. The effect of gibberellic acid (GA3), putrescine, moist chilling, and level of ripeness of seeds on subsequent germination was also investigated. Seeds of G. lutea showed physiological dormancy (final germination percentages ranged from 0% to 11%, depending on the accession) and GA3 enhanced seed germination drastically in all the accessions. The highest germination (99%) of GA3-treated seeds was reached at 15 °C. Final germination percentage and germination rate (as expressed by mean germination time), as well as seed mass and seed water content, varied significantly among accessions. In general, 1 year moist chilling did not significantly enhance G. lutea seed germination. For most accessions, no significant differences were found between fully ripe seeds and less ripe seeds for seed water content, seed mass, and seed germination. Applications of GA3 were always most effective than those of putrescine for increasing seed germination.


2006 ◽  
Vol 57 (12) ◽  
pp. 1249 ◽  
Author(s):  
C. J. F. Fowler ◽  
D. W. Turner ◽  
K. H. M. Siddique

Uniform imbibition and germination of field pea (Pisum sativum L.) seeds is very important for sprout production for human consumption. The imbibition and germination of 3 cultivars of field pea, Dunwa, Dundale, and Helena, each grown at Mullewa, Merredin, and Scaddan in the grainbelt of Western Australia, were investigated in laboratory experiments. The ability of field pea to germinate was affected by cultivar and the environment under which seed development occurred on the parent plant. Averaged over locations, germination of the cv. Dundale (82%) was lower than of Dunwa (93%) or Helena (95%). Germination of seeds ranged from 85% for those grown at Merredin to 91% at Scaddan and 94% at Mullewa. The effect of growing location on germination was most pronounced in cv. Dundale from Merredin where the largest number of hard seeds was observed. Initial seed water content was positively (r2 = 0.55*) correlated with germination across cultivars and sites. Small and large seeds within a seed lot with the same initial seed water content had a similar germination percentage. During imbibition, water entered the seed through the strophiole and this would be an appropriate place to look for a mechanism that affects imbibition. Careful selection of cultivar and favourable growing site should improve germination for the sprout producer.


Weed Science ◽  
1986 ◽  
Vol 34 (2) ◽  
pp. 260-265 ◽  
Author(s):  
Tim R. Murphy ◽  
Billy J. Gossett ◽  
Joe E. Toler

Seed dormancy and soil longevity characteristics of three weedy cowpea [Vigna unguiculata(L.) Walp.] cultivars were investigated. Seed germination was maximum at 40 C; however, ‘Clay’ had greater germination than ‘Black’ or ‘Red Ripper’ cowpea at temperatures ≥ 20 C. Concentrated sulfuric acid soaks, hot (70 C)-water soaks, and piercing the seed coat promoted germination. Seed with an initial water content of 12.3% were stored at relative humidities ranging from 0 to 60% at 25 C. After 4 weeks of storage at relative humidities of 0 to 50%, seed water content varied from 4.6 to 11.4%. Germination and hard seed content was 11% or more and 89% or less, respectively, for seed with water content ranging from 6.9 to 11.4%. Except for seed with an initial water content of 6.9%, cowpea seed water content increased after 3 weeks of storage in a 70% relative humidity environment. Rehydration increased germination for seed with initial water content of 9.2% or more, but not for seed with initial water content of 8.4% or less. In mid-November 1981 and 1982, Black, Clay, Red Ripper, and sicklepod (Cassia obtusifoliaL. # CASOB) seed were buried at soil depths of 2.5, 7.5, and 15 cm for 3, 6, and 9 months. Seed survival of Black and Red Ripper was similar to that of sicklepod; however, longevity of Clay seed was less than sicklepod. Survival was greater for seed buried in 1981 than in 1982 because of low seed water content of the 1981 seedlots.


1992 ◽  
Vol 117 (3) ◽  
pp. 463-466
Author(s):  
C.K. Wan ◽  
F.G. Dennis

The roles of inhibitors in the seedcoat and locules and of seed water content in fruit-induced dormancy of apple (Malus domestics Borkh.) seeds were investigated. Seeds were after-ripened at 5C for various periods up to 12 weeks: 1) in the locules of intact fruits or half-fruits, 2) on wire mesh over moist filter paper, which simulated the locule in preventing leaching, or 3) on moist filter paper. The seeds were subsequently germinated in the locules of half-fruits, on screen, or on moist paper. In some experiments, the seeds were soaked in distilled water before or after after-ripening, or the embryos were excised before germination. The results indicate that fruit volatiles are unlikely to inhibit germination of seeds after-ripened in the fruit. Although limited water content reduced the ability of the seeds to germinate, it did not prevent after-ripening. An unidentified inhibitor(s) present in the locule and on the surface of the seed appears to be the major factor(s) preventing germination in the fruit, as seeds after-ripened on moist paper germinated well on paper or screen but poorly in the locule. The inhibitor(s) appears to be metabolized or to break down spontaneously when seeds are after-ripened on a screen, suggesting that the locule serves as a reservoir of the inhibitor as long as the seed remains in the fruit.


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