scholarly journals (209) Development of Germinability and Desiccation Tolerance in Lettuce Seeds

HortScience ◽  
2006 ◽  
Vol 41 (4) ◽  
pp. 1070C-1070
Author(s):  
Roel Rabara ◽  
Samuel Contreras ◽  
David Tay ◽  
Mark A. Bennett ◽  
Miller B. McDonald

Germinability and desiccation tolerance are important attributes that seeds acquire during their development. The timing in the expression of these characteristics is important to understand how environmental conditions affecting the mother plant influence seed quality. Lettuce plants (cv. Tango) were cultivated in the greenhouse. Seed germination, under light and darkness, was evaluated in fresh and dry seeds at 3, 5, 7, 9, 11, 13, 15, and 17 days after flowering (DAF). Desiccation was performed ≈1 h after harvest by placing the seeds at 25 °C and ≈53% RH. The seed moisture level after desiccation decreased from ∼14% for 3 DAF seed to ∼7% for 7 DAF seed, and then remained constant until the last sampling. Seeds achieved maximum dry weight (physiological maturity) at ∼13 DAF. Germination of fresh seeds increased from 0% at 3DAF to ∼80% at 5 DAF, reaching 100% at 7 DAF. Dry seeds did not germinate when they were 3 or 5 DAF. Seeds at 7 DAF had ∼10% germination and at 9 DAF ∼100%. When germinated in the dark, an increase in germination from 0% in fresh seeds at 3 DAF to 50% germination at 5 DAF was observed. However, seeds at 9 DAF had dark germination values that decreased to 0% and increased again to ∼70% germination at 13 DAF. Dry seeds had no dark germination until 7 DAF, with variable and low germination (below 20%) until 11 DAF, then germination reached a maximum of ∼55% at 13 DAF and decreased to below 10% at 17 DAF. According to these results, lettuce seed germinability and desiccation tolerance were reached sooner than physiological maturity. In the dark, germination of fresh seeds presented a curve with two peaks suggesting that, depending on the seed developmental stage, two different physiological mechanisms restrict dark germination.

2007 ◽  
Vol 47 (6) ◽  
pp. 683 ◽  
Author(s):  
Pippa J. Michael ◽  
Kathryn J. Steadman ◽  
Julie A. Plummer

Seed development was examined in Malva parviflora. The first flower opened 51 days after germination; flowers were tagged on the day that they opened and monitored for 33 days. Seeds were collected at 12 stages during this period and used to determine moisture content, germination of fresh seeds and desiccation tolerance (seeds dried to 10% moisture content followed by germination testing). Seed moisture content decreased as seeds developed, whereas fresh (max. 296 mg) and dry weight (max. 212 mg) increased to peak at 12–15 and ~21 days after flowering (DAF), respectively. Therefore, physiological maturity occurred at 21 DAF, when seed moisture content was 16–21%. Seeds were capable of germinating early in development, reaching a maximum of 63% at 9 DAF, but germination declined as development continued, presumably due to the imposition of physiological dormancy. Physical dormancy developed at or after physiological maturity, once seed moisture content declined below 20%. Seeds were able to tolerate desiccation from 18 DAF; desiccation hastened development of physical dormancy and improved germination. These results provide important information regarding M. parviflora seed development, which will ultimately improve weed control techniques aimed at preventing seed set and further additions to the seed bank.


1995 ◽  
Vol 22 (1) ◽  
pp. 22-26 ◽  
Author(s):  
J. F. Spears ◽  
G. A. Sullivan

Abstract Classification of peanuts (Arachis hypogaea L.) based on pod mesocarp color has become a popular means of estimating maturity of runner peanuts. This study was initiated to determine if the hull mesocarp color is related to seed maturity of virginia-type peanuts and to evaluate changes in quality as seed mature. Cultivars NC 7 and NC 9 peanuts were harvested by hand in 1990, 1991, and 1992. Pods were separated according to mesocarp color. Seed moisture content and dry weight within a maturity class varied with cultivar and production year. Germination of NC 7 seed grown in 1990 and 1992 increased as seed approached maturity. Immature NC 9 seed grown in 1991 and 1992 had substantially lower germination than seed from mature pods. There was no increase in germination during maturation of NC 7 seed harvested in 1991 or NC 9 from 1990. Seed leakage during imbibition, measured by electrical conductivity, decreased as seed matured. The lowest leakage levels occurred when seed had reached physiological maturity. Germination following accelerated aging (AA) increased as seed matured. Maximum AA germination of NC 7 occurred when seed had reached 77, 84, and 100% of their final dry weight in 1990, 1991, and 1992, respectively. NC 9 seed achieved maximum germination following AA after the seed amassed at least 90% of their final dry weight.


1991 ◽  
Vol 1 (3) ◽  
pp. 179-185 ◽  
Author(s):  
C. Pieta Filho ◽  
R. H. Ellis

AbstractThe field emergence ability of a total of 88 seed lots of spring barley (Hordeum vulgare L.) harvested serially during development in 2 years was compared, as was the size of the resultant seedlings. For seedsproduced in each year, field emergence and the mean dry weight of emerged seedlings were significantly greater for seed lots harvested some timeafter physiological maturity (end of the seed-filling period) than for those harvested at or before this developmental stage. This is compatiblewith results for the potential longevity of these lots. It is concluded that barley seed quality continues to increase after physiological maturity, and that the developing seeds attain maximum quality (however this is assessed) close to when the seed crop can be combine harvested. Positive correlations were detected between seedling emergence and seed dry weight (P<0.05) and between the mean dry weight of emerged seedlings and seed dry weight (P<0.005) among seed lots harvested close to when maximum quality was attained in four seed production environments.


HortScience ◽  
2005 ◽  
Vol 40 (3) ◽  
pp. 778-781 ◽  
Author(s):  
Andrés R. Schwember ◽  
Kent J. Bradford

Seed priming (controlled hydration followed by drying) is used to alleviate high temperature inhibition of germination and improve seedling emergence of lettuce (Lactuca sativa L.) and other species. However, seed priming can also reduce the longevity of seeds during dry storage. Alternative drying methods [i.e., slow drying or moisture content reduction (MCR) before drying] can extend seed longevity compared to conventional rapid drying procedures after priming. Three postpriming drying treatments were tested on `Conquistador' and `Genecorp Green' lettuce seeds: rapid drying, slow drying and MCR (10% fresh weight loss, then held at 100% relative humidity (RH) for 6 hours, followed by rapid drying). The effects of the postpriming treatments on seed quality and longevity were compared based upon standard germination tests, germination rates, thermogradient table tests, controlled deterioration (CD) tests, and headspace volatiles analysis. The latter may be correlated with seed longevity as release of volatiles (e.g., acetaldehyde, ethanol) is associated with lipid peroxidation. While neither slow drying nor MCR before drying restored lettuce seed longevity to that of the control (not primed) seeds, the MCR method generally gave better results in both cultivars compared to rapid drying. Among the CD test conditions used, 50 °C and 75% RH gave the most consistent results for estimating potential longevity. Headspace volatile emissions from both control and primed lettuce seeds were very low and were not well correlated with seed longevity. Alternative postpriming drying regimes can extend seed longevity while retaining the beneficial effects of priming.


1992 ◽  
Vol 2 (2) ◽  
pp. 81-87 ◽  
Author(s):  
I. Demir ◽  
R. H. Ellis

AbstractChanges in tomato (Lycopersicon esculentumMill.) seed quality were monitored during seed development and maturation in glasshouse experiments in 2 years. The end of the seedfilling period (mass maturity) occurred 35–41 d after anthesis (differing among trusses) in 1989 and 42 d after anthesis in 1990. Seed moisture contents at this developmental stage were 53–72% (wet basis), while the onset of ability to germinate (during 21-d tests at 20°/30°C) and the onset of tolerance to rapid enforced desiccation occurred just before (1990) or just after (1989) mass maturity. In 1989, seed quality was assessed primarily by seedling size in a glasshouse experiment; maximum mean seedling dry weight 25 d after sowing was not achieved until 24–40 d after mass maturity. In 1990, seed quality was assessed primarily by germination following storage; maximum normal germination after 35 d in storage at 40 °C with 14 ± 0.5% moisture content was attained 23 d after mass maturity, but with little difference among seed lots harvested 10 d earlier or up to 30 d later. The results contradict the hypothesis that maximum seed quality is attained at the end of the seed-filling period and that seed viability and vigour begin to decline immediately thereafter.


1991 ◽  
Vol 1 (3) ◽  
pp. 149-162 ◽  
Author(s):  
J. B. Dickie ◽  
K. May ◽  
S. V. A. Morris ◽  
S. E. Titley

AbstractMature seeds of Norway maple (Acer platanoides L.) are tolerant of desiccation, at least to moisture contents of about 7% (fresh weight basis), but those of sycamore (Acer pseudoplatanus) are killed by drying below about 45% moisture content. Sycamore seeds are thus recalcitrant; while the classification of those of Norway maple as orthodox is confirmed by the fact that between 19% and 7.5% moisture content their longevity is increased in a predictable way by reduction of seed moisturecontent. However, the period of useful storage of the latter in seed banks may be much less than for many crop species. The rates of water loss to a dry environment of both fruits and seeds of sycamore are much less than those of Norway maple, suggesting a degree of desiccationavoidance in the desiccation-intolerant species. Seed physiological maturity (maximum dry weight) occurred 2–3 weeks earlier in Norway maple than insycamore, but in both species this occurred about 150–160 days after peak flowering. Tetrazolium staining is a good indicator of embryo viability in both species, correlating well with germination test results. In Norway maple both methods of viability testing indicated that whole-seed desiccation tolerance coincided with the attainment of maximum dry weight. Tetrazolium staining indicated the development of desiccation tolerance in the radicles/hypocotyls of both species approximately 2–4 weeks before physiological maturity. Possible correlation between changes in the level of embryo dormancy during development and the acquisition of desiccation tolerance are discussed.


2019 ◽  
Vol 4 (1) ◽  
Author(s):  
Devi Rusmin ◽  
Ireng Darwati

The experiment was conducted at Gunung Putri Experimental Station and PlantPhysiology Laboratory of Indonesian Medicinal and Aromatic Crops Research Institute(IMACRI), from November 2008 to July 2009. The aim of the experiment was to determinephysiological maturity of Pimpinella pruatjan seed and to study its morphological structures.Observation and sampling using one hundred plants with four replications. Results of theexperiment showed that the physiological seed maturity on the first and third umbell of P.Pruatjan was achieved at 7 weeks after anthesis, and physiological seed maturity on thesecond umbell was achieved at 8 weeks after anthesis. Seed dry weight on the physiologicalseed maturity on first, second and third umbells were 166,87; 158,20, and 141,35 mg/100pericarp, respectively. Germination percentage and germination speed on the first, secondand third umbells were 5,75 % and 0,22 %/etmal; 22,75 % and 0,94 %/etmal; 10,50 % and0,38 %/etmal, respectively.Keywords: flowering, pruatjan, seed quality, morphology


2021 ◽  
Vol 17 (2) ◽  
pp. 522-527
Author(s):  
Kishore Kumar ◽  
Jitendra Kumar S. Hilli

An investigation was undertaken with main objectives to know the effect of desiccants on seed quality parameters of crop seeds during storage and to assess the benefit cost ratio of storage method (economics) in wheat with initial seed moisture content of 12.3 %, was carried out at Department of Seed Science and Technology, College of Agriculture, UAS, Dharwad. Quantity of desiccants stored per kilogram of seed in wheat seeds is 0.37 kg for zeolite beads, one kg for silica gel, calcium carbonate and control without desiccant in airtight container. The experiment was laid out in Completely Randomized Design with four treatments and five replications. Seed stored with zeolite beads recorded the highest germination (88.8 %) which was on par with silica gel (87.2 %) at the end of storage period. Lower seed moisture and hundred seed weight was observed in the seeds stored with silica gel at the end of storage period. Higher shoot length, root length, seedling vigour-I and seedling dry weight was observed in seeds stored with zeolite beads which was on par with Silica gel at the end of storage period. compared to control. Therefore, it can be concluded that the zeolite beads can safely be used for seed drying without impairment in seed quality.


2013 ◽  
Vol 21 (2) ◽  
pp. 131-138
Author(s):  
Deepu Mathew ◽  
S.D. Doijode ◽  
K. Madhavi Reddy

ABSTRACT The feasibility of extending the storability of fresh hot pepper seeds, by modifying the storage atmosphere, using the respiration inhibitors and seed desiccants was examined. Halogens such as chlorine, bromine and iodine and methanol, ethanol and potassium permanganate were used for a period of 22 months under accelerated ageing conditions of high seed moisture and temperature. The various seed quality parameters - viability, vigour, speed of germination, seedling dry weight, and moisture content were evaluated. In the untreated control, decreased seed viability was observed within 10 months of storage. However, iodine and chlorine were proved effective in retaining high seed viability up to 90.7 and 88.0%, respectively, even after 22 months of storage. Chlorine treatment was able to retain the seed vigour (904.0), iodine (766.4), KMnO4 (754.4) and methanol (566.7) whereas the value of vigour index in control was 72.0. Chlorine and iodine were on par in their ability to maintain the speed of seed germination (25.2 and 24.8, respectively), followed by KMnO4 (20.2). Seedling dry weight was proved as a parameter not sensitive in estimating the seed quality since even after 22 months storage of seeds at atmospheres of chlorine, iodine, KMnO4 and methanol did not show any differences. KMnO4 sharply reduced the seed moisture content from 9.83 to 7.89% providing better storability over the control.


2016 ◽  
Vol 6 ◽  
pp. 111
Author(s):  
Víctor Pecina ◽  
Enrique Navarro ◽  
Héctor Williams ◽  
Raúl Rodríguez

The production of sorghum hybrids depends almost entirely on one genic-cytoplasmic sterility system (Milo-Kafir, A1 Cytoplasm), therefore its importance in increasing the diversity of the number of male-sterile sources, as the named A2 Cytoplasm. This system was introduced at the Rio Bravo Experiment Station (lNIFAP-CIRNE) in Tamaulipas, Mexico, where ge-netic material and seed production were developed. The objetive was to compare the seed quality ofthe isocytoplasmic genotypes (A1 and A2 cytoplasm). A Completely Radomized Experimental Design with Factorial Arrangement and two replications was used. The results show that there were no differences between the two types of cytoplasm (A1 and A2) for the following quality traits: volumetric weight of seeds, 1000 seeds' weight, germination(G) and seedling dry weight (SDW), through nine months of storage; whereas in vigor (G and SDW after fast aging) the A2 cytoplasm surpassed the Al cytoplasm and the same behavior was observed on the seed harvested at its physiological maturity, while at harvest maturity the Al was superior in G and SDW.


Sign in / Sign up

Export Citation Format

Share Document