Complete Germination Research Articles

Interaction of light and gibberellin on potato seed germination

The percentage of germination in recently harvested potato seed was greater in darkness or short photoperiods and at low light intensities. A combination of gibberellic acid and reduced amounts of light gave nearly complete germination in ten days.

Genetigal and physiological causes of the variation of radiosensitivity in barley and maize

In a few experiments in barley and maize inherited factors influencing the radiosensitivity were studied. The Bulgarian barley variety No. 1337 was found to be much less radiosensitive, with respect to seedling growth reduction following γ-irradiation of seeds, than the Swedish variety No. 02104. Following neutron irradiation, following storage of γ-irradiated dry seeds, or following γ-irradiation of pre-soaked seeds, the difference between the two varieties was appreciably smaller. The difference is thus consistent with a lower oxygen concentration in the seeds of No. 1337. A certain (negative) correlation was established between “water-sensitivity” of barley seeds and their sensitivity to γ-radiation. Seeds of inbred lines and hybrids of maize exhibited characteristic variations of the radiosensitivity with respect to seedling growth inhibition. Two single crossed hybrids and their double cross were less sensitive to γ-radiation as well as neutrons than their four parent inbred lines. These variations of radiosensitivity were not correlated to frequencies of neutron induced chromosomal aberrations. The lines differ in sensitivity with respect to mutation induction, however, one hybrid giving, compared to the parent lines, a 3–6 times lower frequency of “waxy” pollen grains after semi-chronic γ-irradiation during meiosis. The fast-growing inbred line Wf-9 was appreciably less sensitive than the others, with respect to seedling growth inhibition, chromosomal aberrations as well as mutation induction. When the complete germination inhibition induced by high doses (0·2–1 Mrad) was studied, the order of sensitivity of the lines became completely different, with no special resistance in the hybrids. The latter were somewhat superior, however, with respect to elongation of root cells in the surviving seeds.

LONG-TERM INFLUENCE OF SOIL AMENDMENTS ON GERMINATION OF CONIDIA.

Washed conidia of Gliocladium fimbriatum and Fusarium solani f. phaseoli required a carbon and nitrogen source for complete germination. Filtered aqueous extracts and membrane-expressed soil solution supported germination of washed conidia of both fungi, but germination of G. fimbriatum was completely inhibited in non-filtered aqueous soil extracts and on soil–cellophane–agar plates, whereas conidia of F. solani f. phaseoli germinated readily in both instances.The long-term influence of certain soil amendments on the capacity of the soil solution to support germination of conidia was investigated. Inhibition of germination of conidia of F. solani f. phaseoli and G. fimbriatum in filtered aqueous extracts of cellulose-amended soil with a C/N ratio higher than 25/1 and barley-amended (C/N ratio, 55/1) soil was overcome by the addition of 5 p.p.m. nitrate nitrogen to the soil during extraction. Chemical analysis of cellulose-amended (C/N ratio, ∞) soil indicated that most of the inorganic nitrogen had been immobilized. Germination in aqueous extracts of soybean- (C/N ratio, 7/1) and alfalfa-amended (C/N ratio, 18/1) soil or non-amended soil was not inhibited. Germination of F. solani f. phaseoli conidia added directly to cellulose-amended (C/N ratio, ∞) soil in 2% sucrose solution was also inhibited, whereas conidia added in 2% sucrose to non-amended soil germinated readily. Cellulose-amended (C/N/P ratio, 25/1/0.1) soil was the only soil that consistently demonstrated fungistatic activity to germination of conidia of F. solani f. phaseoli on soil–cellophane–agar plates. Membrane expressed soil solutions of the cellulose-amended soil, however, did not demonstrate fungistatic activity to germination of conidia.

Seed Dormancy in Green Needlegrass1

SynopsisDormancy was present in seeds harvested at all stages of maturity. The tetrazolium viability test gave an accurate measure of the germination potential of a seed lot. A laboratory germination procedure was developed which induced practically complete germination and equaled tetrazolium readings.

THE GERMINATION OF SPORANGIOSPORES OF RHIZOPUS ARRHIZUS; SPORE SWELLING AND GERM-TUBE EMERGENCE.

Summary: The germination of sporangiospores of Rhizopus arrhizus was investigated, and differing requirements found for the initiation of germination, spore swelling and germ-tube emergence. The initiation of germination, as indicated by the commencement of swelling and by the spores becoming permeable to methylene blue, requires the presence of glucose or fructose. Maximal spore swelling requires in addition the presence of a nitrogen source, PO4 3− and K+ or Na+. If these requirements are satisfied, the increase in spore diameter with time is approximately linear for 8 hr, implying the maintenance of a constant rate of water uptake per unit area of spore surface for this period. If germinating spores are transferred to a medium lacking glucose, swelling soon ceases. The rate of swelling is identical at widely differing osmotic pressures. It is suggested that water uptake by the germinating spore is an active process, requiring energy. Germ-tube emergence from some spores can be obtained with glucose alone, but for germ-tube production from all spores other nutrients must also be supplied. If glucose is present, spores can take up sufficient nutrients in 1–2 hr to permit complete germination in the absence of exogenous nutrients several hours later. Depending on conditions, germ-tube production can occur after either slight or massive spore swelling. The effect of anaerobic conditions on germination was also examined and found to permit only partial spore swelling and greatly diminished germ-tube production.

CARBON DIOXIDE FIXATION IN GERMINATING CONIDIOSPORES OF ASPERGILLUS NIGER

Incorporation of 14CO2 into conidiospores of Aspergillus niger (strain 1617) was investigated under various cultural conditions.The conidia incubated in a complete germination medium incorporated 14CO2 very actively without any lag period. By using various media for incubation, it was found that the more favorable the medium for the germination, the more active was the 14CO2-incorporation. In the germinating conidia fed with 14CO2, a large amount of radioactivity was found in the protein fraction as well as in the acid-soluble fraction, in which ATP was revealed to be one of the major substances to be labeled within a short period. Quickly labeled were also nucleic acids, in which adenine, cytosine and uracil were strongly labeled, while thymine and guanine were less strongly, but definitely, labeled even at the onset of germination.Based on these observations as well as those made earlier of the phosphorus and alanine metabolisms of germinating conidia, inferences and discussions were made of the biochemical events occurring in the early phase of conidia germination.

Responses of Seeds of Pinus taeda & P. strobus to Light

Seeds of loblolly pine, Pinus taeda L., and of white pine, P. strobtus L., which require a long moist treatment at a low temperature (stratification) for complete germination, were chosen for this study. Seeds of the former species require 30 to 90 days at 2 to 3 C and those of the latter 30 days at 10 C or 60 days at 4 C (27). The purpose of the work was to investigate responses of these seeds to red and far-red radiation, which controls germination (4) through the phytochrome pigment (13). Phytochrome exists in two interconvertible forms (4). The P660 form absorbs red light and is converted to the P730 form believed to be active biologically. The P730 form absorbs far red and is converted to the inactive P660 form. The P730 form also reverts in darkness to the P660 form (13). Most seeds in which the action of phvtochrome has been demonstrated germinate promptly and completely after one brief exposure to light (23). A few seeds in a sample of seed of Virginia pine, P. virginiana Mill., also germinate in response to a single brief irradiation, but most of them require a short period at a low temperature before they germinate in response to light (26). This change in light requirement of Virginia pine seeds after a short period at a low temperature made it important to measure similar changes in loblolly and white pine seeds, which reportedly require appreciable stratification.

COMBINED EFFECTS OF GIBBERELLIN AND 2,4-D ON DORMANT SEEDS OF STINKWEED (THLASPI ARVENSE L.)

Concentrations of 50 and 500 p.p.m. gibberellin were used alone and in combination with 2,4-D sodium salt solutions ranging from 0.00001 to 8000 p.p.m. acid equivalent, in Petri dishes, with dormant seeds of stinkweed (Thlaspi arvense L.), to determine the effects of these treatments or of subtoxic amounts of 2,4-D alone, on germination and growth. About 90% germination within 2 weeks was induced by the 50 p.p.m. gibberellin and was not augmented by the very dilute concentrations of 2,4-D. Complete germination occurred within only 8 days with 500 p.p.m. gibberellin alone. Strengths greater than approximately 0.02 p.p.m. of 2,4-D retarded shoot elongation and concentrations greater than about 0.5 p.p.m. of 2,4-D progressively reduced germination associated with either 50 or 500 p.p.m. gibberellin. Concentrations of 2,4-D higher than approximately 200 p.p.m. prevented both concentrations of gibberellin from causing any true germination. Beyond 200 p.p.m. of 2,4-D there was still, however, a broad range within which gibberellin was able to cause a definite initial phase of the germination process characterized simply by rupture of the seed coat without protrusion of root and stem. This response could not be prevented by 2,4-D at concentrations lower than 4000 p.p.m. in counteraction with 50 p.p.m. gibberellin, or at dosage lower than about 7000 p.p.m. in association with 500 p.p.m. gibberellin. Potential practical significance of the work is considered.

Presence of Gibberellin-like Substances in Lettuce Seed

GIBBERELLINS and gibberellin-like substances are being shown to occur in an increasing number of higher plants. Immature seeds of numerous species contain particularly large amounts of these substances1, but the levels in mature seeds of the same species are much lower2. Certain seeds respond very strongly to applied gibberellin, this being particularly evident in certain ‘light-requiring’ seeds, for example, those of lettuce3,4 and Arabidopsis thaliana 5, in which gibberellin treatment may result in complete germination in the dark. The obvious first step towards understanding the physiological significance of this gibberellin action is to determine whether gibberellin-responsive seeds contain endogenous, gibberellin-like growth regulators. The present communication reports on such studies with mature seeds of lettuce (Lactuca sativa L.).

Effects of Heat and Loss of Moisture on the Dormancy of Barley

IN a paper on the effects of desiccation on delayed germination in barley it is suggested that ripening and germination are directly related to the moisture-content of the grain1. The observation is made that complete germination occurred when the moisture content naturally fell to 12.7 per cent or when artificial drying was used.

On Dormancy and Seed Germination in Hemerocallis

1. Seeds obtained from selfing Hemerocallis minor and from intercrossing hybrid Hemerocallis plants of complex origin were used in a series of experiments in 1953, 1954, and 1955 to determine the nature of seed dormancy in this genus. 2. Freshly harvested seeds germinate to a limited extent but only within a narrow temperature range. Minimum, optimum, and maximum temperatures for non-stratified seeds were found to be above 16⚬, 22⚬-25⚬, and below 33⚬ C., respectively. 3. Differential peeling experiments demonstrated that an endosperm membrane one cell thick, which covers the protruding tip of the hypocotyl, was responsible for delayed germination at 22⚬ C., while at 16⚬ C., in addition to the membrane, endosperm storage tissue restricts gaseous diffusion. Complete germination was brought about at 16⚬ C. either by removing a wedge of storage tissue to expose about one-fourth of the embryo axis or by completely excising the embryo, as compared with little or no germination of intact seeds. Sealing of the hypocotyl tip with petroleum jelly or lanolin, following removal of the diminutive endosperm membrane, greatly retarded germination. 4. Results from seeds planted in soil in greenhouse flats and stratified outdoors during the winter for various periods indicated that 1 or 2 months of stratification sufficed for the breaking of dormancy. Stratified seeds germinated over a greater temperature range than did non-treated seeds. 5. Controlled stratification experiments carried out in Petri dishes indicated that 0⚬-10⚬ C. was the general range for after-ripening, with the optimum being near the lower temperatures. Inconsistent results were obtained with stratification temperatures below freezing. As little as a day of stratification at the optimum temperature was sufficient to increase slightly the percentage of germination at 16⚬ C. incubation over that of the controls. Longer periods of stratification were necessary at the higher temperatures of the effective range to bring about corresponding increases of germination. After-ripened seeds germinate over a greater temperature range than do non-stratified seeds. Thus, conditioned seeds germinate readily at 10⚬ C. and even lower. After-ripened seeds likewise are able to germinate at a slightly higher temperature than do non-conditioned seeds, providing the inhibitory effect of the enveloping structures has been removed. 6. After-ripening occurred only at low temperatures and only when the seeds were moist. The optimum degree of moisture saturation seems to be a function of the stratification temperature. Thus, with stratification at 3.5⚬ C., seeds reacted similarly over a wide range of moisture content, but, when stratified at -4⚬ C., the degree of saturation appeared to determine the efficiency of stratification more critically. 7. Oxygen must be available to the seeds if effective after-ripening is to occur during stratification. 8. The after-ripening effect persists for as long as 1 month after stratification if the seeds are maintained in an air-dry condition. 9. Presence of an inhibitor substance could not be demonstrated in non-stratified seeds, nor could any evidence be found of a stimulatory substance in after-ripened seeds. 10. Possible interpretations of the results obtained are discussed in the light of other investigations in the field of seed dormancy.

Biochemical aspects on the germination of conidiospores of Aspergillus niger.

Biochemical events occurring in synchronously germinating spores of Aspergillus niger strain 1617 were investigated. The spores were found to require l-proline (or l-alanine), glucose and phosphate for the complete germination. The germination process in the above synthetic medium could be divided into three phases: endogenous swelling, exogenous swelling and sprouting. The first swelling phase was not influenced by the severe environmental factors so far tested, while the second phase was found to be affected by them, especially the CO2 concentration. Rates of increase in cellular substances and in consumption of environmental substances changed markedly after germ tubes sprouted. The first cellular synthesis thus far detected was nucleic acid synthesis in the exogenous swelling phase. At the end of this phase accumulation of free amino acids, mainly glutamic acid and alanine, was observed. Protein synthesis then followed. A conspicuous increase in O2-uptake commenced in parallel with the active synthesis of protein, when germ tubes began to sprout.

Dormancy in Barley

WHEN applied to germination, ‘dormancy’ and ‘maturity’ are not precise terms, and their meaning therefore depends on the particular test which is used. The data in my communication1 relate to tests in which the conditions were optimal, in all respects, for the germination of barley grains. Complete germination was obtained immediately after the drying treatment, and must necessarily be attributed to the removal of inherent dormancy in the grains which would riot otherwise germinate. There is the further significant fact that this response was not only obtained during storage after harvest, but also when the grains were ripening, and at the harvest-ripe stage.

Spore germination in the genus bacillus: the modification of germination requirements as a result of preheating.

Summary: Spore suspensions of Bacillus megaterium germinated spontaneously after heat treatment. The extent of germination depended on the degree of close packing of the suspension, the temperature and duration of heating, and on the presence of water. Spontaneous germination was not inhibited by heating with cyanide, azide, 2:4-dinitrophenol or sodium iodoacetate, but was significantly inhibited by sodium fluoride. Freshly harvested spores of a laboratory strain of Bacillus cereus required either inosine or a mixture of alanine + tyrosine + adenosine for optimal germination. After prolonged storage or a short heat treatment, adenosine alone stimulated rapid and complete germination. Heat activation did not occur in the absence of water. It was inhibited to some extent by sodium fluoride. Similar results were obtained with B. cereus, NCTC 8035. After preheating, spores of a virulent and an avirulent strain of Bacillus anthracis germinated more rapidly and completely in a mixture of adenosine + tyrosine + alanine, but not in adenosine alone. Inosine stimulated rapid and complete germination of heated suspensions, and was consistently more effective than adenosine. Adenosine deaminase activity has been found in extracts from resting spores of the laboratory B. cereus and the avirulent strain of B. anthracis but not in B. megaterium.

Dormancy of the Seed in the Groundnut

Dormancy is characteristic of seeds. Agricultural crops and refers to the resting period required give complete germination on sowing from the time of matu.rka. harvest. Seeds of certain varieties of plants are dormant and r some resting period for germination while others are non-dormanta. sprout if sown soon after harvest. Some seeds even germinate while on the plants themselves if conditions are favourable.

NUTRIENT REQUIREMENTS IN THE GERMINATION OF THE CONIDIA OF GLOMERELLA CINGULATA

American Journal of BotanyVolume 32, Issue 6 p. 296-298 Article NUTRIENT REQUIREMENTS IN THE GERMINATION OF THE CONIDIA OF GLOMERELLA CINGULATA Ch'wan-Kwang Lin, Ch'wan-Kwang Lin Plant Pathology Laboratory, The University of Nanking, Chengtu, ChinaSearch for more papers by this author Ch'wan-Kwang Lin, Ch'wan-Kwang Lin Plant Pathology Laboratory, The University of Nanking, Chengtu, ChinaSearch for more papers by this author First published: 01 June 1945 https://doi.org/10.1002/j.1537-2197.1945.tb05122.xCitations: 10AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article.Citing Literature Volume32, Issue6June 1945Pages 296-298 RelatedInformation

A STANDARD GERMINATION TEST FOR DOUGLAS FIR SEED

Seed of Douglas fir (Pseudotsuga taxifolia (Lamb.) Britt.) is often difficult to test for germination capacity. Complete and rapid germination can be obtained from seed which has been stratified for six to ten weeks in moist sand at a temperature just above the freezing point. This method is suggested as a standard technique for testing Douglas fir seed.

Immediate germination of certain selfed and hybrid potato seed

A study of twenty-two genetically different samples of recently harvested seed showed marked differences in the degree of delayed germination exhibited, some samples completing germination before transplanting time whereas other samples required approximately ninety days to complete germination. Observations indicate that the old seed when planted may exhibit delayed germination.

The Relation of Moisture Content and Time of Harvest to Germination of Immature Corn1

After-ripening of immature corn is coincident with the loss of moisture. Immature corn planted immediately after harvest exhibits great variability in time of germination. With a decrease in moisture content, the percentage of seeds germinating is increased and the variability in time required for complete germination is decreased. The moisture content of immature seeds must be reduced to approximately 25% before normal germination occurs. Corn kernels require a minimum of approximately 35 and 60% of moisture in whole grain and embryo, respectively, before germination can occur. It is suggested that the mechanism which inhibits the normal germination of newly harvested immature corn operates in the scutellum rather than in the endosperm or pericarp.

Normal pregnancy and childbirth with complete germination of the liver with cancer metastases

A 36-year-old, re-pregnant patient, in the first months of her last pregnancy, there is a rapid growth of cancer of the left breast.