Showing papers on "Germination published in 1976"
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TL;DR: The initial water uptake rate was found to decrease as the external water poten tial decreased, due to reduced diffusivity to water of the seed coats, but the final water gained by imbibition was sufficient to ensure full germination.
Abstract: Water uptake patterns and germination rates of chickpea (Cicer arietinum L.) and vetch (Vicia faba L.), as affected by constant and changing external water potential, were studied experimentally. The initial water uptake rate was found to decrease as the external water poten tial decreased, due to reduced diffusivity to water of the seed coats, but the final water gained by imbibition was sufficient to ensure full germination. Germination rate decreased with a decrease in the external water potential. The data presented suggest that more work should be directed toward a better understanding of the effects of external water potential changes on the enzymatic activity during and after the imbibition stage.
137 citations
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TL;DR: Germination, hyphal growth and root penetration from Endogone spores and from root-segments infected by Endog one, were studied on agar-coated glass slides buried in soil.
Abstract: Germination, hyphal growth and root penetration from Endogone spores and from root-segments infected by Endogone , were studied on agar-coated glass slides buried in soil. In most cases the spores germinated readily within 16 days, with or without the presence of onion roots. Germ tubes grew either through the old spore attachment or direct through the spore walls. Hyphae from spores were not attracted to the onion roots, until in very close proximity, when they formed fan-like structures of predominantly septate hyphae. Successful infections only occurred from aseptate hyphae, which developed later in the pre-infection fans. Hyphae from infected root-segments were always aseptate, and infected the roots without forming fan-like structures. The different infection patterns are probably due to different nutrient supply in resting spores and mycorrhizal root-segments.
134 citations
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TL;DR: Marked differences were found among local populations in germination behavior and the evidence suggests that these differences result in part from genetic adaptation to agronomic practices.
Abstract: Genetic variability affecting duration of primary dormancy is demonstrated in natural populations of wild oats. Marked differences were found among local populations in germination behavior. The evidence suggests that these differences result in part from genetic adaptation to agronomic practices.
130 citations
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129 citations
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TL;DR: Germination of the seeds at constant temperatures or with daily shifts in temperature is related to the membrane transition temperature for permeation by amino acids, which indicates prominent increase in permeability of the plasmalemma in the 30 to 35 C range for 8 of the 10 kinds of seeds studied.
Abstract: Leakages of amino acids and/or fluorescent material as functions of temperature between 15 and 40 C are reported for imbibed seeds of Avena fatua L., Lactuca sativa L., Barbarea vulgaris R. Br., Amaranthus albus L., Abutilon theophrasti Medic., Lychnis alba Mill., Daucus carota L., Setaria faberi Herrm., Setaria viridis (L.) Beauv., and Datura stramonium L. The leakage indicates prominent increase in permeability of the plasmalemma in the 30 to 35 C range for 8 of the 10 kinds of seeds studied. Germination of the seeds at constant temperatures or with daily shifts in temperature is related to the membrane transition temperature for permeation by amino acids. Seeds of A. albus and A. theophrasti, which did not show membrane changes in the 25 to 40 C range, germinated best at 35 to 40 C; the other seeds germinated best below 30 C. Seeds of B. vulgaris showed rapid permeation of limiting membranes upon initial wetting with water, which was indicative of membrane disorder when dry. Leakage under anaerobiosis was observed for S. faberi seeds.
123 citations
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TL;DR: It was possible to obtain greater than 90% yields of germinated E. mosseae Nicolson & Gerdemann spores on distilled water agar with improved germination of some spore sources by the addition to the agar of nicotinic acid or thiamine HCl.
Abstract: Although reliable germination of Endogone spores has previously been difficult to achieve, it was possible to obtain greater than 90% yields of germinated E. mosseae Nicolson & Gerdemann spores on distilled water agar. Zinc and manganese, at the concentrations present in many commercially available agars could completely inhibit spore germination. Spores from freshly harvested sporocarps germinated slowly and this was improved by storing the sporocarps at 6° for several weeks. The germination of some spore sources was improved by the addition to the agar of nicotinic acid or thiamine HCl.
107 citations
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TL;DR: Examination of stomach contents of hundred of small mammal animals shows that small mammals which eat hypogeous fungi are spore vectors as has been demonstrated for coprophilous fungi and dispersal through rodents is certainly secondary.
Abstract: (1976). Germination of Spores of Glomus Macrocarpus (Endogonaceae) After Passage Through a Rodent Digestive Tract. Mycologia: Vol. 68, No. 2, pp. 433-436.
93 citations
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TL;DR: It is concluded from the high Q10 figures for germination in the cold that the failure of germination may result from a denaturation of proteins.
Abstract: SUMMARY
At 2O°C, cucumber and mung bean seeds germinate rapidly. As the temperature is lowered to 14°C, the time required for 50% germination increases with a Ql0 of about 2. However, between 14 and 11°C, Q10 rises to 60–1600 (cucumber) and 87 (mung bean); below 11°C only a small percentage of seeds will germinate. At 10°C, the roots never extend to more than 1.5 mm, while a length of 2.5 mm is necessary for germination. Exogenous supply of various amino acids and hormones fails to alleviate the block to germination in the cold. The mitotic index of root cells in cucumber seedlings is low at 5°C. However, at 22°C the seeds can germinate even under conditions that inhibit mitosis (0.02% colchicine or following γ-irradiation). There is little indication of leakage from cucumber seeds in the cold. Arrhenius plots of the respiration of imbibed seeds, of the growth of 1-cm long roots and the respiration of root tips are a1! linear. It is concluded from the high Q10 figures for germination in the cold that the failure of germination may result from a denaturation of proteins.
85 citations
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83 citations
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TL;DR: This study deals with an aspect of germination which has to do with both physiology and ecological strategy: how the rate of seed germination is affected by clustering of seeds into dense arrays, and the relationship between this response to density and the propensity of a species to be colonizing or weedy as opposed to being a member of an indigenous, closed plant community.
Abstract: Germination is a critical stage in the life of a plant. While much is known about the physiological processes which occur at that time, the adaptive aspects of germination strategies have received much less attention (Kozlowski 1972; Heydecker 1973). However, population biologists are aware of the importance of these strategies and have emphasized their critical role in the dynamics of plant populations (Harper 1965; Cohen 1967). This study deals with an aspect of germination which has to do with both physiology and ecological strategy: how the rate of seed germination is affected by clustering of seeds into dense arrays, and the relationship between this response to density and the propensity of a species to be colonizing or weedy as opposed to being a member of an indigenous, closed plant community. A few reports on density-dependent percentages and/or rates of germination are scattered in the literature, e.g. for pollen (Brewbaker & Majumder 1961), fungus spores (Toth 1973) and seed (Ballard 1958; Palmblad 1968). The responses of germination to greater density have included both increases (Ballard 1958; Brewbaker & Majumder 1961; Linhart & Pickett 1973; Toth 1973) anct decreases (Palmblad 1968; Toth 1973). However, comprehensive reviews of seed biology (Kozlowski 1972) and seed ecology (Heydecker 1973) do not discuss this phenomenon.
82 citations
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TL;DR: It is proposed that the function of this enzyme is to mobilise the endosperm cell wall polysaccharides as a nutrient source for the growing embryo.
Abstract: Lettuce seeds (Lactuca sativa L. cv. Grand Rapids) stimulated to germinate by gibberellin and red light produce large amounts of endo-β-mannanase. This enzyme increases markedly following radicle emergence and is capable of degrading mannose-containing polysaccharides, which are the major components of the endosperm cell wall. Non-germinated seeds contain little enzyme and under conditions where gibberellin- or red light-stimulated germination is prevented (eg. by abscisic acid or prolonged far red light) enzyme levels remain low. Cycloheximide inhibits the increase in enzyme levels when supplied to germinating seeds, but the enzyme once produced is stable in vivo in the presence of this inhibitor for at least 24h. The majority of the extractable mannanase activity is located in the endosperm and we propose that the function of this enzyme is to mobilise the endosperm cell wall polysaccharides as a nutrient source for the growing embryo.
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TL;DR: Germination of spores of Glomus mosseae on agar media was inhibited by excess nutrient such as provided in standard Potato Dextrose or Nutrient Broth Agars, unless very low concentrations of the re...
Abstract: Germination of spores of Glomus mosseae on agar media was inhibited by excess nutrient such as provided in standard Potato Dextrose or Nutrient Broth Agars, unless very low concentrations of the re...
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TL;DR: Experiments with germinating seeds of Wayne soybean show that between the 4th and the 8th hour of germination, respiration experiences a transition from predominantly "alternate" respiration, which is sensitive to salicylhydroxamic acid, to a cyanide-sensitive respiration.
Abstract: Experiments with germinating seeds of Wayne soybean (Glycine max Merr.) show that between the 4th and the 8th hour of germination, respiration experiences a transition from predominantly "alternate" respiration, which is sensitive to salicylhydroxamic acid, to a cyanide-sensitive respiration. The dependence of early germination stages on alternate respiration is reflected in several types of seed functions, including subsequent root growth rate, chlorophyll synthesis, and germination itself. The early period of germination is shown to require a normal O(2) tension, which is no longer a requirement at later stages. The changing sensitivity to cyanide and to salicylhydroxamic acid is found to be common to seven different types of germinating seeds. It is proposed that the alternate pathway of respiration provides something essential for the completion of the earliest stages of seed germination.
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TL;DR: The results indicate that gibberellic acid is capable of breaking dormancy in these species with dormant seeds, but kinetin proved to be ineffective.
Abstract: The interaction between hormones and salinity on seed germination of three halophytic taxa in the genus Suaeda: S. maritima (L.) Dum. var. flexilis Focke and var. macrocarpa Moq., and S. depressa (Pursh) Wats, was studied. Exogenous applications of kinetin and gibberellic acid (GA3) were applied in order to determine if either of these growth-promoting hormones would promote germination in the two dormant taxa, Suaeda depressa and S. maritima var. flexilis and to see if osmotically induced dormancy by NaCl could be alleviated. Our results indicate that gibberellic acid is capable of breaking dormancy in these species with dormant seeds, but kinetin proved to be ineffective. A seed dormancy that was induced by osmotic stress could also be alleviated by treatments with gibberellic acid. Endogenous concentrations of both cytokinins and gibberellins were measured in seeds exposed to osmotic stress (0.85 M NaCl), and we found a reduction in cytokinin activity in these three taxa. Gibberellin-like activity was reduced in S. depressa when seeds were soaked in 0.85 M NaCl.
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TL;DR: The germination and dormancy of Themeda australis, Danthonia spp.
Abstract: The germination and dormancy of Themeda australis, Danthonia spp., Stipa bigeniculata and Bothriochloa macra were investigated in whole dispersal units or caryopses. Germination of non-dormant units of the four species was not affected by light but was delayed by low temperatures. Such temperature regimes depressed the germination capacity of Themeda while alternating temperatures with a range greater than 10°C depressed the germination of Bothriochloa. The level of germination of Danthonia and Stipa was not affected by any of the temperature regimes used. Dormancy was reduced either by the application of gibberellic acid at concentrations of 100 ppm to 1000 ppm or by stratification. In addition, application of kinetin ( 10 -4M ) or opening the lemma suture broke the dormancy of Stipa dispersal units. The breakdown of dormancy during dry storage was also examined. Temperature alternations with maximum temperatures greater than 40°C reduced the level of dormancy of Themeda and Stipa within 1-2 months.
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TL;DR: During the overall germination process in the light-requiring seeds of Chenopodium album L, two sites of hormonal action can be distinguished and a second site oformonal action is located during the progress of growth inside the covering structures.
Abstract: During the overall germination process in the light-requiring seeds of Chenopodium album L. two sites of hormonal action can be distinguished.
The start of visible growth is induced in darkness by the gibberellins 4 and 7 (GA4+7) or by ethylene. Added cytokinins are inactive although 8-14C-kinetin shows rapid penetration into the seed and rapid turnover. The induction of growth by GA4+7 and the uptake of 8-methylene-14C-GA3 are enhanced at lower pH values. Prolonged incubation in darkness results in a decreased responsiveness of the seeds towards GA4+7 and ethylene.
A second site of hormonal action is located during the progress of growth inside the covering structures. ABA inhibits radicle growth, while GA4+7, GA3, kinetin, zeatin and ethylene reduce the inhibition.
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TL;DR: In this article, the interactive effects of temperature with matric and osmotic potential on germination characteristics of three dryland species, Danthonia caespitosa Gaudich, Atriplex nummularia Lindl and A. vesicaria Hew.
Abstract: Studies evaluating simultaneous effects of more than one environmental factor on germination are rather scarce. Population dynamics of plant species would be understood better provided these effects are known. A study was undertaken to investigate the interactive effects of temperature with matric and osmotic potential on germination characteristics of three dryland species, Danthonia caespitosa Gaudich, Atriplex nummularia Lindl. and A. vesicaria Hew. ex Benth. Matric potentials were simulated by aqueous solutions of polyethylene glycol (mol. wt. 20,000) and their effects were compared with those of osmotic potential created by sodium chloride solutions. The rate and total germination of all the species declined with decreasing water potential. The germination rates increased with increasing temperature but final germinations were highest at intermediate temperatures (20 to 25 C). All species germinated better at low water potentials in the vicinity of the optimum temperatures. Interactive effects of temperature with both types of water potential were highly significant for all species. In general, osmotic effects were qualitatively similar to those of matric potential, although asmotic inhibition of germination was reduced at low temperatures. Both Atriplex had reasonable germination at extreme temperatures (5 C, 40 C) while D. caespitosa did not germinate at all. At low water potential (−15 bars) nummularia germinated in the range of 15 to 40 C, D. caespitosa germinated only at 25 C while A. vesicaria had poor germination at all temperatures. The order of species with respect to their capability to germinate against environmental stress was A. nummularia > A. vesicaria > D. caespitosa. It follows that because of capability of Atriplex spp. to withstand extreme temerature and water potential, germination is possible following rains during summer as well as winter, however Danthonia is likely to germinate only during spring and autumn.
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01 Jan 1976TL;DR: Reversal of the red effect by far-red light confirms that phytochrome is the photoreceptor, and many inhibitory effects of low-intensity far- red light can be interpreted in terms of the maintenance of a low level of Pfr.
Abstract: This chapter discusses phytochrome control of seed germination in relation to the light environment. Positive responses to both short and long periods of light show an action peak in the red region of the spectrum, corresponding to the absorption peak of the Pr form of phytochrome. Reversal of the red effect by far-red light confirms that phytochrome is the photoreceptor. This was first demonstrated in seeds of Lactuca sativa . Seeds of some species, such as Limonium vulgare , are stimulated only by a long period of red light, suggesting that there is a requirement for Pfr action over a prolonged period. In species, such as Amaranthus caudatus , where seed germination is inhibited by prolonged exposure to light, far-red and blue are the most effective parts of the spectrum. Seeds exposed to prolonged white light (high Pfr/P) germinate on transfer to darkness, whereas seeds exposed to prolonged far-red light (low Pfr/P) do not germinate on transfer to darkness unless given an irradiation with red light. Many inhibitory effects of low-intensity far-red light can be interpreted in terms of the maintenance of a low level of Pfr.
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TL;DR: Among various compounds tested, acetate was most effective in stimulating the germination of akinetes, and Radioactivity of the incorporated 14C-acetate was mainly recovered in ethanol-soluble fraction, especially in glutamate and leucine.
Abstract: Effects of some physical and chemical factors on the germination of akinetes of Anabaena cylindrica were studied. The akinetes placed in an inorganic medium germinated, after a certain lag period, in the light but not in the dark. At temperatures above 35°, no germination occurred even in the light. This germination was inhibited by 3, 4-dichlorophenyldimethylurea (DCMU), an inhibitor of photosynthesis. The optimum pH for germination in the inorganic medium was in the range of 7.0 to 8.0. Oxygen was essential for the germination of akinetes. Among various compounds tested, acetate was most effective in stimulating the germination. Acetate was easily taken up by akinetes, but it did not affect the respiration. Radioactivity of the incorporated 14C-acetate was mainly recovered in ethanol-soluble fraction, especially in glutamate and leucine.
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TL;DR: The intensity and frequency of burning was shown to affect the species composition of the regeneration very significantly and the optimum temperatures for germination were determined for the more common species.
Abstract: SUMMARY The importance of dormant buried seeds of understorey species of the wet sclerophyll forests of northern N.S.W. is discussed in relation to their germination ability following fire or mechanical or chemical abrasion. The optimum temperatures for germination were determined for the more common species. The intensity and frequency of burning was shown to affect the species composition of the regeneration very significantly.
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TL;DR: The slow growth of the seedlings accords with the normal low nutrient availability in heath soils but seedlings show little capacity for rapid exploitation of any temporary increase of available nutrients after fire.
Abstract: Effects of heating dry seed were investigated in Banksia serratifolia and B. ericifolia. Seeds were inviable after 7 min exposure at 150°C or higher temperatures but remained viable after exposure at 100°C and lower temperatures. Imbibed seeds show no dormancy, and seeds survive fire insulated from heat in the thick woody follicles which may persist unopened for several years on the parent plant but open following fire.
Effects of nutritional supplements were observed in the seed germination and seedling survival and growth of Banksia serratifolia, B. aspleniifolia and B. ericifolia. Germination with radicle and hypocotyls extension was not significantly affected by a wide range of mineral nutrient regimes. In pot experiments using a heath soil seedling survival and growth were adversely affected by moderate additions of phosphate with surviving seedlings showing toxicity symptoms and poor development of proteoid roots. Moderate supplements of potassium had no adverse effect, and in B. serratifolia and B. ericifolia lessened the adverse effects of phosphate addition. The slow growth of the seedlings accords with the normal low nutrient availability in heath soils but seedlings show little capacity for rapid exploitation of any temporary increase of available nutrients after fire.
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TL;DR: Achene dispersal, seed germination, and seedling establishment of Hieracium aurantiacum L. were studied in an 18-year-old abandoned field community and indicated a decline in reproductive output as the season progressed.
Abstract: Achene dispersal, seed germination, and seedling establishment of Hieracium aurantiacum L. were studied in an 18-year-old abandoned field community. Sexual reproductive output from selected patches declined rapidly after anthesis early in the season. The decrease in the number of achenes produced per head indicated a decline in reproductive output as the season progressed. Most of the achenes collected were deposited within 1 m of the source path. Achenes deposited near the source were larger and had a higher percentage viability than those deposited up to 3 m from the source. Seedling survival was higher within the parent patch compared with that at 5 dm in the adjacent herbaceous vegetation. Germination of the seeds gathered earlier in the season was higher than that of seeds gathered at monthly intervals as the season progressed. Cold treatment enhanced germination of seed produced late in the season but had little effect on seed produced early in the season.
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TL;DR: In considering the breaking of dormacy in rice seeds, it may be neces-sary to check the interaction between momilactones and GA or IAA which has an important role during rice seed germination.
Abstract: In order to isolate growth and germination inhibitors from the hulls of dormant rice seeds, the seeds of a Japonica cultivar 'Koshihikari' and an Indica one 'Surjamukhi', which have strong dormancy, were used. The rice hull (ca 200kg) was soaked in 80% methanol for about 2 months. The methanol extracts were concentrated to an aqueous phase by the flash evaporator at below 40°C. The aqueous phase was extracted with chloroform and the active fraction was moved in chloroform. The active chloroform fraction was successively fractionated by organic solvents : n-hexane, benzene, ether, ethylene chloride, and ethyl acetate. The biological activity of each extract was checked by lettuce germination test. The active fraction checked was further separated according to solubility in dilute acid or base. The neutral fraction of benzene and ether extracts showed a strong inhibitory activity. The active fraction was used for further chromatographic study. By the silica gel thin layer chromatography with a developing solvent, benzene : ethyl acetate (10 : 1), two active compounds were crystallized and were identified as momilactone-A (C20H2603) and -B (C20H26O4) The momilactones inhibited the seed germination and the seedling growth of rice and lettuce at a concentration of 10-3M. Especially, these substances remarkably inhibited the root growth of rice seedling at 10-5-10-3M. Momilactone-B had stronger inhibition than momilactone-A. The inhibitory activity of momilactone-B was similar to that of a typical growth regulator, abscisic acid. 'Koshihikari' contained more momilactone-A than momilactone-B, while 'Surjamukhi, which has stronger dormancy than 'Koshihikari', held more mornilactone-B than momi-lactone-A. It was supposed that the content of momilactone-A and -B in rice seeds might vary with the rice cultivar. The inhibitory activity of momilactones was partially reduced by GA3 or IAA. In considering the breaking of dormacy in rice seeds, it may be neces-sary to check the interaction between momilactones and GA or IAA which has an important role during rice seed germination.
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TL;DR: A defined germination medium comprised of L-alanine, L-glutamic acid, adenosine, para-aminobenzoic acid, and calcium and magnesium ions provided a germination rate nearly equal to that of complex media.
Abstract: Spores of Streptomyces viridochromogenes were removed from the surface of solid media with glass beads and suspended in a buffer-detergent solution. Addition of yeast extract and glucose resulted in rapid loss of refractility of the spores. Appearance of germ tubes followed. Germination was accompanied by a decrease in the optical density (OD) of the suspension. The OD decrease was used as an assay for germination. A defined germination medium (DGM) comprised of L-alanine, L-glutamic acid, adenosine, para-aminobenzoic acid, and calcium and magnesium ions provided a germination rate nearly equal to that of complex media. The germination rate was essentially the same if D-alanine and D-glutamate replaced the L-isomers. The optimum pH and temperature for germination were 7.0 and 35 C. Germination was absolutely dependent on the presence of CO2. Spores harvested after growth for longer periods than the usual time (10 days) became less germinable in DGM. The same was observed for spores grown at 37 C as compared with 30 C. Spores incubated in DGM for various time periods before being transferred to a buffer solution did not continue to germinate. Spores harvested after growth of eight species of Streptomyces did not show a decrease in OD when incubated in yeast extract medium. Another strain of S. viridochromogenes did exhibit an OD decrease in the medium. Comparative properties of spores of streptomycetes, fungi, and bacilli are discussed.
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TL;DR: It is concluded that only germination of pollen in vitro is significantly correlated with berry and seed set and thus gives a reliable estimate of male fertility, while the peroxidase method is not useful for the Solanum material studied.
Abstract: Three staining methods (acetocarmine, fuchsin and oxidation of benzidine) and germination in vitro and in vivo were applied to estimate pollen fertility in Solanum species and dihaploids. Pollen was divided into six classes based on shape and contents of the grains. With acetocarmine, fuchsin, peroxidase and germination in vitro 4, 3, 2 and 1 classes, respectively, are supposed to be included in the percentage of ‘good’ pollen as measured by these methods. This percentage therefore, in more than 96% of the cases studied, shows a decrease in the order indicated. Neither aging of pollen at room conditions nor collecting pollen from flowers on 1–9 days after anthesis does influence the percentage of ‘good’ pollen with acetocarmine and fuchsin, whereas this percentage drops sharply to zero with peroxidase and germination in vitro. The latter two methods apparently measure as ‘good’ pollen only the grains with living cytoplasm. When pollen is collected at three successive dates from the same flowers the percentage of ‘good’ pollen drops sharply with all methods used. There is a relation between quantity of pollen per flower and pollen quality (% ‘good’), low-quantity pollen containing significantly lower percentages of ‘good’ pollen than medium- and high-quantity pollen. The latter two are not significantly different in this respect.
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TL;DR: A correlation coefficient between germination and emergence indicates that germination at 10 C would be effective in the selection of cold tolerant types, and growth analysis studies on seedlings up to the unifoliolate leaf stage showed that cold tolerant cultivars had a higher fresh weight at a specific age at 10-C.
Abstract: Emergence experiments were conducted on 32 soybean (Glycine max (L.) Merrill) cultivars at a 2.5-cm depth in Guelph loam soil at 10, 20 and 30 C. Differences in emergence were found among cultivars at 10 C but not at 20 and 30 C. Results of the emergence experiment at 10 C permitted classification of cultivars into cold tolerant, intermediate and intolerant groupings. There was no close relationship between maturity group and degree of cold tolerance. Differences in speed of germination were found among cultivars at 10 C. A correlation coefficient (r = +0.616) between germination and emergence indicates that germination at 10 C would be effective in the selection of cold tolerant types. Growth analysis studies on seedlings up to the unifoliolate leaf stage showed that cold tolerant cultivars had a higher fresh weight at a specific age at 10 C. This was attributed to the faster emergence of the cold tolerant cultivars.
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TL;DR: Of the 25 species of shrubs common in poplar box lands, 17 are considered to have reached the status of being a "woody weed" in New South Wales and/or Queensland.
Abstract: Of the 25 species of shrubs common in poplar box lands, 17 are considered to have reached the status of being a "woody weed" in New South Wales and/or Queensland. Thickening up of scrub in pastoral areas appears to have been episodic after periods of above-average rainfall. Germination of seed may occur at most times of the year if soil moisture is high. Fire promotes germination of species with hard seeds (some Acacia, Cassia and Dodonaea spp.). Increased shrub density usually follows soil disturbance if seed is present, and once established, the individuals of most apecies appear to be long-lived. Productivity of shrub communities is commensurate with rainfall. The species are well adapted to tolerate drought and they retain leaves under extreme water stress. Most species flower and set seed each year in the spring and summer period but in more arid parts of poplar box lands some species reproduce opportunistically after good rainfall. In favourable conditions most species produce copious quantities of seed. Dormancy is common in seed recently shed and loss of dormancy may occur within months or up to 3 years after seed shed. All species are subject to invertebrate and vertebrate predation and death of individuals or whole populations may sometimes result. A few species are moderately palatable to domestic livestock and native herbivores; the majority are rarely eaten even by starving animals. The regenerative ability of shrubs following fire or grazing differs amongst species and is affected by shrub size.
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TL;DR: The life-span of coffee seeds is extended when seeds are stored with high moisture content as mentioned in this paper, and the seeds are always higher in the dark than in the light, while the opposite combination of regulators delays germination.
Abstract: The life-span of coffee seeds is extended when seeds are stored with high moisture content. Germination in darkness is always higher than in the light. Exogenous gibberellic acid and abscisic acid inhibit germination while kinetin reverses this inhibitory effect. Low levels of endogenous gibberellin- and abscisic acid-like and high levels of cytokinin-like substances favour germination while the opposite combination of regulators delays germination.