scholarly journals Emergence of `Genesis' Triploid Watermelon following Mechanical Scarification

1999 ◽  
Vol 124 (4) ◽  
pp. 430-432 ◽  
Author(s):  
John R. Duval ◽  
D. Scott NeSmith

Production of triploid watermelon [Citrullus lanatus (Thunb.) Matsum & Nakai] transplants is hindered by poor, inconsistent emergence, and frequent seed coat adherence to cotyledons. Seed coat adherence leads to weakened and slow growing plants. High seed costs, coupled with stand establishment problems, discourages transplant producers from growing this crop. Improvement of triploid watermelon emergence will lessen financial risks to growers and transplant producers and will provide a more reliable production system. Mechanical scarification was evaluated as a means to overcome inconsistent emergence and seed coat adherence. Seeds of `Genesis' triploid watermelon were placed in a cylinder with 100 g of very coarse sand (1.0 to 2.0 mm diameter) and rotated at 60 rpm for 0, 6, 12, 24, and 48 hours in a series of experiments. Number of emerged seed was recorded daily, to obtain emergence dynamics. No significant differences were observed in seed coat adherence among treatments. The longest duration of scarification However, enhanced emergence as compared to the control in three of four experiments. These data support earlier suggestions that a thick or hard seed coat is a factor contributing to poor germination and emergence of triploid watermelons.

HortScience ◽  
1998 ◽  
Vol 33 (4) ◽  
pp. 597a-597
Author(s):  
John R. Duval ◽  
D. Scott NeSmith

Production of triploid watermelon [Citrullus lanatus (Thunb.) Matsum & Nakai] transplants is hindered by low and nonuniform emergence, and seedcoat adherence. Seedcoat adherence leads to weakened and slow-growing plants. High seed costs are prohibitive to many transplant growers. Improvement of emergence would lower financial risks to growers and transplant producers. Mechanical scarification was examined as a means to decrease the impact of both problems. Seeds of `Genesis' triploid watermelon were placed in a cylinder with 100 g of very coarse sand and rotated for 6, 12, 24, and 48 hours at 60 rpm. Nontreated seeds were used as a control. Data were taken daily on emergence and seedcoat adherence. The experiment was repeated at three temperature regimes. No significant differences were observed in seedcoat adherence. Scarification, however, did significantly improve emergence under test conditions.


2001 ◽  
Vol 52 (10) ◽  
pp. 985 ◽  
Author(s):  
Z. H. Miao ◽  
J. A. Fortune ◽  
J. Gallagher

Selection and breeding for yield and adaptation to environmental conditions often changes a number of characteristics of crops, and may influence the value of seed for animals. A series of experiments was conducted to evaluate the effect of breeding and growing conditions on the structure and degradability of lupin seed coats. Breeding has had significant influences on both seed size and seed coat structure of lupins. For instance, cultivars of Lupinus angustifolius released in 1987 and 1988 tended to have smaller seeds with a thicker seed coat than those released in 1971 (P < 0.05). Selection for soft seeds has resulted in a reduction of seed coat thickness in L. angustifolius. Hardseeded and roughseeded lines of L. cosentinii had thicker coats (P < 0.05) than softseeded and smoothseeded, respectively. The main contributor to the thick seed coat of hardseeded lines was a layer of cells known as the hourglass layer, which is located between the outer palisade and inner parenchyma. Anatomical analysis revealed that the soft seed coat tended to have short and round cells, whereas the hard seed tended to have long cells in the palisade layer. Smooth seeds had round cells in the subpalisade, but rough seeds had long cells in this layer. Although the seed coats of lupins contained about 80% crude fibre, with L. cosentinii and L. pilosus having more fibre than L. angustifolius, the fibre in lupin seed coats was highly digestible by sheep.


1987 ◽  
Vol 17 (4) ◽  
pp. 294-298 ◽  
Author(s):  
R. J. Hoff

The inner layer of the seed coat, a papery membrane, and physiological conditions of the gametophyte–embryo were shown to be major sites of dormancy in seed of western white pine. The hard seed coat layer was a minor site. With no stratification, 7% of the seeds were not dormant, 9% were dormant because of the hard seed coat, 34% were dormant because of the inner seed coat, and 50% were dormant because of physiological conditions of the gametophyte–embryo. These values varied with stratification times and seed lots (families).


2019 ◽  
Vol 41 (3) ◽  
pp. 318-327
Author(s):  
Rosemeire Carvalho da Silva ◽  
Andreza Cerioni Belniaki ◽  
Elisa Serra Negra Vieira ◽  
Francine Lorena Cuquel ◽  
Maristela Panobianco

Abstract: Calophyllum brasiliense Cambess. (guanandi) is a native species with medicinal potential and also generates expectation for commercial use (wood) and for recovery of degraded areas. These seeds have physical and mechanical dormancy, requiring techniques for dormancy release; knowledge of seed and seedling morphology that assists laboratory analysis and propagation of the species is also necessary. The objective of this study was to describe the morphological structures of the seeds and normal and abnormal seedlings of guanandi, and also investigate if complete extraction of the endocarp and the seed coat to overcome dormancy will affect the morphology and initial plant development, and consequently production of transplants. Guanandi seeds are large (1000 seed weight of 1480.9 g) with a hard seed coat; cotyledons account for most of the embryo and serve as a reserve; the embryonic axis is small (1.0-2.0 mm) in relation to the seed, yet it is differentiated. The seedlings have hypogeal cryptocotylar germination, with cotyledonary petioles, taproot, and epicotyl developing into a long stem and a tip protected by cataphylls. The main abnormalities in seedlings are related to the root system. Extraction of the endocarp and seed coat does not alter the morphology of seedlings and promotes their greater development, which may be an advantageous strategy.


2009 ◽  
Vol 55 (6) ◽  
pp. 396-400
Author(s):  
Hongmao Zhang ◽  
Wei Wang

Abstract Some rodent-dispersed seeds have a hard seed-coat (e.g.woody endocarp). Specific scrapes or dental marks on the hard seed-coat left by rodents when they eat these seeds can be used to identify seed predators. In this study we measured the morphological traits of endocarp-remains of seeds of wild apricot Prunus armeniaca used by Chinese white-bellied rats Niviventor confucianus and Korean field mice Apodemus peninsulae. We established their Fisher’s linear discriminant functions to separate endocarp-remains between the two predators. A total of 90.0% of the endocarp-remains left by Korean field mice and 88.0% of those left by Chinese white-bellied rats were correctly classified. The overall percentage of correct classification was 89.0%. One hundred and sixty endocarp-remains of unknown what species predated them were classified using the functions. The method may allow more reliable quantitative studies of the effects of Chinese white-bellied rats and Korean field mice on seed consumption and dispersal of wild apricot and this study might be used for reference in other studies of seed predators identification on hard seeds.


Our Nature ◽  
1970 ◽  
Vol 7 (1) ◽  
pp. 177-181 ◽  
Author(s):  
B. Niroula ◽  
D. Parajuli ◽  
S. Jha

All the freshly collected mature seeds of M. pudica were greenish in colour, whereas 7 year old stored seeds were a mixture of greenish and brownish seeds. The greenish seeds had hard seed coat and acid treated as well as sand rubbing for 6-10 min greatly enhanced their germination percentage. The brownish seeds were simply the deteriorated form of greenish seeds. Leaves and pods had higher contribution to total plant dry weight in ungrazed field and in pot-cultured plants clipped a month before flowering. The young shoots of the plant had 18.9% crude protein, 0.46% phosphorus and 25.4% crude fibre on dry weight basis.Key words: Hard seed coat, Mimosa pudica, scarification, dry matter productionDOI: 10.3126/on.v7i1.2568Our Nature (2009) 7:177-181  


Author(s):  
R. N. Paul ◽  
G. H. Egley

Hard seed coat material is extremely difficult to prepare for observation at the EM level. Seed coat segments are usually removed for embedding and sectioning, which results in loss of tissue juxtaposition. Observation and monitoring reactions of the intact seed coat under experimental procedures such as tracking dye penetration into seeds make seed coat dissection unfeasible. Efforts to apply analytical EM methods such as STEM/EDS analysis, are restricted by the limiting effect of section thickness on X-ray signal. We investigated the ultrastructure of dry seeds by treating them with various metallic staining solutions and observing the trimmed block faces with the SEM in backscatter mode. Good structural information was obtained as well as visualization of a specific tissue layer that accumulates lead.Intact seeds were incubated in several aqueous solutions including: 2% w/v uranyl acetate; 1% w/v OsO4; 2% ferrous chloride (Followed by 5% potassium ferricyanide to form an insoluble precipitate) ; and various lead solutions including Reynolds lead citrate.


1996 ◽  
Vol 10 (1) ◽  
pp. 22-28 ◽  
Author(s):  
Philip Westra ◽  
Calvin H. Pearson ◽  
Randal Ristau ◽  
Frank Schweissing

This study was conducted to gain insight into the soil seedbank dynamics of Venice mallow in two irrigated Colorado soils. Venice mallow plants produced an average of 3100 seeds per plant under noncompetitive irrigated conditions. Venice mallow seeds collected from three regions of Colorado and stored at 25 C averaged 95% dormancy and less than 4% nonviable seeds 6 mo after harvesting. Percent nonviable seeds in soil remained relatively constant over 2 yr. Most seeds germinated within the first 3 mo after burial in the first crop production year. Seed dormancy decreased to an average of 40% after 3 mo of burial in cultivated soil at Fruita and Rocky Ford, and thereafter remained relatively constant for 21 mo. Fruita seeds underwent lessin situgermination than seeds from Greeley or Rocky Ford. Innate seed dormancy was lower at Fruita (27%) than at Rocky Ford (39%). Enforced dormancy remained constant over a 21-mo period and was similar for both locations (32%). Seeds buried for 2 yr at Fruita underwent greaterin situgermination (42%) than at Rocky Ford (27%). At Fruita, the level of enforced dormancy was higher and the level of innate dormancy lower at the 20-cm than the 2-cm depths. Venice mallow seed dormancy likely is due to an impermeable hard seed coat.


2015 ◽  
Vol 25 (4) ◽  
pp. 402-408 ◽  
Author(s):  
Torbjørn R. Paulsen ◽  
Louise Colville ◽  
Matthew I. Daws ◽  
Sigrunn Eliassen ◽  
Göran Högstedt ◽  
...  

AbstractIn imbibing seeds, resumption of metabolism leads to the unavoidable release of volatile by-products that are perceived as cues by rodent seed predators. The crypsis hypothesis proposes that the primary function of a water-impermeable, hard seed coat is to reduce rodent seed predation by rendering seeds olfactorily cryptic. In an opinion paper, Jayasuriya et al. (2015) find the crypsis hypothesis unscientific and ‘not consistent with Darwin's theory of evolution by natural selection’. It is unfortunate that Jayasuriya et al. (2015) did not appreciate that the crypsis hypothesis offers an alternative explanation for the evolution of water-impermeable seeds: released seed volatiles are cues used by rodents to locate seeds, and variation in seed-coat permeability leading to differences in seed volatile release represents the variable under selection. Furthermore, the sealing of water-impermeable seed coats imposes a cost of increased generation time and, therefore, dormancy-release mechanisms are expected to subsequently evolve in response to local environmental conditions. We also disagree with most other claims by Jayasuriya et al. (2015), who failed to appreciate how species with dimorphic seeds – one morph with permeable and the other with impermeable seed coats – benefit from rodent caching behaviour and population dynamics. We welcome this opportunity to clarify and elaborate on key features and the evolution of water-impermeable seed coats according to the crypsis hypothesis.


2021 ◽  
Vol 9 (1) ◽  
pp. 43-58
Author(s):  
Nazhira Firda Yulia ◽  
◽  
Supriyanto Supriyanto ◽  
Diana Prameswari ◽  
◽  
...  

Screw tree is a shrub from family Malvaceae that has many benefits in pharmacy. Screw tree seed has very hard seed coat, so the seed must be treated before germination. The aim of this research was to assess the characteristic of fruit and seeds, effect of seed breaking dormancy, and effect of NPK fertilizer dosage on the growth of screw tree (Helicteres isora) seedlings. The results indicated that screw tree fruits belong to dry fruits with capsule form and has 5 follicles that has different direction. Screw tree seed is orthodox type that has 9 ̶ 36 seeds in one follicle with triangle and square shape. Germination technique in laboratory with soaking the seeds in hot water 100oC until the water cool for 48 hours treatment produced the best germination amounting to 65.0%. Germination technique in green house with soaking the seeds in hot water 100oC until the water cool for 24 hours treatment was the best germination amounting to 77.0%. Seedlings fertilized with 1 g NPK doses increased screw tree growth in diameter parameter of 6.35 mm and shoot-root ratio parameter of 3.9 compared to control.


Sign in / Sign up

Export Citation Format

Share Document