Seed development in Malva parviflora: onset of germinability, dormancy and desiccation tolerance

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.

1992 ◽  
Vol 2 (2) ◽  
pp. 89-95 ◽  
Author(s):  
D. Gray ◽  
J. R. A. Steckel ◽  
L. J. Hands

AbstractThe effects of development of leek seeds at 20/10°, 25/15° and 30/20°C (day/night) and drying of seed harvested at different developmental stages on subsequent performance were examined in each of 3 years. An increase in temperature from 20/10° to 30/20°C reduced mean seed weight from 2.90 to 2.55 mg as a result of a reduction in the duration of seed growth from 80 to 55 days; seed growth rate was unaffected. Seed moisture content reached a minimum, up to 35 days after the attainment of maximum seed dry weight and 115, 90 and 70 days after anthesis at 20/10°, 25/15° and 30/20°C, respectively. The curves relating seed moisture to time for each temperature regime were mapped onto a single line accounting for >90% of the variation in moisture content, using accumulated day-degrees >6°C instead of chronological time. Seeds were capable of germinating when seed moisture contents were >60% (fresh weight basis), but maximum viability and minimum mean time to germination were not attained until seed moisture contents at harvest had fallen to 20–30%. Germination was little affected by temperature of seed development. Drying immature seeds increased percentage germination. Growing seeds at 30/20°C and drying at 35°C and 30% RH raised the upper temperature limit of germination compared with growing at 20/10°C and drying at 15°C and 30% RH.


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.


2006 ◽  
Vol 20 (4) ◽  
pp. 862-866 ◽  
Author(s):  
Peter H. Sikkema ◽  
Darren E. Robinson ◽  
Christy Shropshire ◽  
Nader Soltani

Weed management is a major production issue facing otebo bean growers in Ontario. Field trials were conducted at six Ontario locations during a 2-yr period (2003 and 2004) to evaluate the tolerance of otebo bean to the preplant incorporated (PPI) application of EPTC at 4,400 and 8,800 g ai/ha, trifluralin at 1,155 and 2,310 g ai/ha, dimethenamid at 1,250 and 2,500 g ai/ha,S-metolachlor at 1,600 and 3,200 g ai/ha, and imazethapyr at 75 and 150 g ai/ha. EPTC, trifluralin, dimethenamid, andS-metolachlor applied PPI resulted in minimal (less than 5%) visual injury and with exception of the low rate of dimethenamid causing a 16% reduction in shoot dry weight and the high rate causing an 8% plant height reduction had no adverse effect on plant height, shoot dry weight, seed moisture content, and yield. Imazethapyr applied PPI caused up to 7% visual injury and reduced plant height, shoot dry weight, and yield 8, 18, and 12% at 75 g/ha and 19, 38, and 27% at 150 g/ ha, respectively. Seed moisture content was also reduced by 0.4% with both rates. Based on these results, otebo bean is not tolerant of imazethapyr applied PPI at rates as low as 75 g/ha, the proposed use rate. EPTC, trifluralin, dimethenamid, andS-metolachlor applied PPI have a 2× rate crop safety margin for use in otebo bean weed management.


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.


2003 ◽  
Vol 13 (4) ◽  
pp. 323-327 ◽  
Author(s):  
T. Mai-Hong ◽  
T.D. Hong ◽  
N.T. Hien ◽  
R.H. Ellis

In the hot and dry conditions in which seeds of the tree legume Peltophorum pterocarpum develop and mature in Vietnam, seed moisture content declined rapidly on the mother plant from 87% at 42 d after flowering (DAF) to 15% at 70 DAF. Dry weight of the pods attained a maximum value at about 42 DAF, but seed mass maturity (i.e. the end of the seed-filling phase) occurred at about 62 DAF, at which time seed moisture content was about 45–48%. The onset of the ability of freshly collected seeds to germinate (in 63-d tests at 28–34°C) occurred at 42 DAF, i.e. about 20 d before mass maturity. Full germination (98%) was attained at 70 DAF, i.e. at about 8 d after mass maturity. Thereafter, germination of fresh seeds declined, due to the imposition of a hard seed coat. Tolerance of desiccation to 10% moisture content was first detected at 56 DAF and was complete within the seed population by 84 DAF, i.e. about 22 d after mass maturity. Hardseededness began to be induced when seeds were dried to about 15% moisture content and below, with a negative logarithmic relation between hardseededness and moisture content below this value.


2004 ◽  
Vol 18 (4) ◽  
pp. 893-901 ◽  
Author(s):  
Peter H. Sikkema ◽  
Nader Soltani ◽  
Christy Shropshire ◽  
Todd Cowan

Weed control in white beans is currently limited by the small number of registered herbicides. The tolerance of two white bean cultivars, ‘AC Compass’ and ‘OAC Thunder’, to various postemergence (POST) herbicides at the maximum use rate and twice the maximum use rate for soybean or corn was evaluated at two Ontario locations in 2001 and 2002. Generally, the two cultivars did not differ in their response to the POST herbicides. POST applications of imazamox plus fomesafen, imazamox plus bentazon, and cloransulam-methyl decreased plant height, shoot dry weight, and yield by as much as 29, 41, and 55%, respectively, and increased seed moisture content up to 3.9%. POST applications of thifensulfuron, chlorimuron, and bromoxynil decreased plant height as much as 57%, shoot dry weight by up to 71%, yield as much as 93% and increased seed moisture content up to 15.5%. Based on these results, AC Compass and OAC Thunder white beans do not possess sufficient tolerance to support the registration of imazamox plus bentazon, imazamox plus fomesafen, cloransulam-methyl, thifensulfuron, chlorimuron, and bromoxynil.


Author(s):  
Offurum Julius Chigozie ◽  
C.M. Morgan

The water content determination of two maize species (Yellow corn- and White corn- ) located at Ohaji in Imo State of Nigeria were  considered in this study. This was motivated by the regular reported cases of the seed post-harvest spoilages, especially in the local communities. And the moisture content of a particular seed could vary according to the various location of crop, presumably due to the soil texture. The moisture content of a given crop seed can influence its storage value, as well as its choice of selection during manufacturing processes. It was, thus, necessary to determine the moisture content of the two maize species (white and yellow corn) from Ohaji in Imo State of Nigeria, in order to identify their dispositions, especially during storage. Modified High Constant Temperature Oven method, as prescribed by the International Seed Testing Association (which involves preliminary pre-drying and grinding), was employed, at a temperature of 102oC. This involved the use of dry-weight technique, which is expressed as a percentage of the dry weight of the seeds. The procedure for each sampling was replicated accordingly, and the mean value identified as the actual result. The moisture content for Sample A (white corn) was found to be 31.7%, while that of Sample B (yellow corn) was found to be 21.5%, which shows that the yellow corn would always have longer storage value than the white corn. As any change in the seed moisture content has a way of affecting its storage life, it is advisable not to store the white corn longer than it could be applied in the yellow corn for a better storage value.Keywords: Determination, Moisture Content, White Corn, Yellow Corn, Dry-weight Basis


2019 ◽  
Vol 33 (3) ◽  
pp. 303-316
Author(s):  
Prihatin Ponco Pamungkas ◽  
Maizar Maizar ◽  
Sulhaswardi Sulhaswardi

The study aimed to determine the effect of giving NPK Grower fertilizer and defoliation to seed development and corn crop production. The design used in this study was a Factorial Completely Randomized Design consisting of two factors. The first factor is NPK Grower (N) fertilizer with a dose of 0, 7.5, 15, 22.5g / plant while the second factor is Defoliation (D) with some 0, 2, 4, all leaves under the cob. The parameters observed were changes in seed dry weight (g), changes in seed moisture content (%), speed of accumulation of dry matter (mg / seeds / day), effective filling time (days), harvest age (days), and dry shelled weight ( g). The last observation data were analyzed statistically and continued with a BNJ follow-up test at the level of 5%. The results showed that interactively giving NPK Grower and Defoliation fertilizer had a significant effect on changes in seed dry weight, changes in seed moisture content, speed of dry matter accumulation, harvest age and dry shell weight. The best treatment is in the combination of 22.5g / plant NPK Grower fertilizer treatment and Defoliation of all leaves under the cob (N3D3). The main effect of NPK Grower fertilizer has a significant effect on all parameters. The best treatment for NPK Grower fertilizer is 22.5g / plant (N3). The main effect of Defoliation has a significant effect on all parameters. Best treatment Defoliate all leaves under the cob (D3).


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.


Sign in / Sign up

Export Citation Format

Share Document