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PubMed2002

[Light quality effect on the seeds germination in tropical pioneer tree Heliocarpus appendiculatus (Tiliaceae)].

The objective of this study was to determine whether seeds of the pioneer tree Heliocarpus appendiculatus possess photoblastic dormancy. Seeds from nine trees were collected in Los Tuxtlas, Mexico. In order to test for the presence of photoblastic dormancy, germination experiments were carried out separately on seeds of each individual tree. The seeds from each tree were sown and subjected to four light treatments: fluorescent white light, red light (660 nm), far red light (730 nm), and darkness. A total of 50 seeds were sown in each plastic Petri dish (three replicates per treatment) on an agar solution. Experiments were carried out at a constant temperature of 20 degrees C, and a 12:12 hr (L:D) photoperiod. In addition, seeds of three individuals were sown on agar and subjected to a light quality gradient from red to far red (1.1-0.2). Results show that final germination percentages of seeds were unaffected by light quality in all individuals. Nevertheless, germination was delayed by 24 hr in the seeds of four individuals under the far red light treatment. By the end of fourth day, final germination did not differ among treatments. Further, germination of the three individuals under the red/far red gradient was unaffected. Seeds of H. appendiculatus lack photoblastic dormancy and germination behavior can not be used to explain the absence of seedlings below the canopy. We propose that this absence is due to the failure of the seedlings to establish themselves under the canopy.

Chi-Square Distribution↗

PubMed2003

[Seed germination characteristics and regeneration mechanism of Stellera chamaejasme population].

Stellera chamaejasme is a perennial herbaceous plant of Thymelaceae, as one of major poisonous plant species to animal, distributing in Northeast, Northwest, and Southeast of China. In some area on the degraded steppes, the plant grew with abnormal abundance and badly endangered the health of animals. The germination capacity of Stellera chamaejasme seed that collected from soil seed bank and immediately gathered from the plant was studied under different temperature, light condition and five pretreatments (rupture seed pericarp, remove seed pericarp, soaked in 98% H2SO4 for 5 min, soaked in 0.2% KNO3 for 24 h, and kept at 10 degrees C for a week). The seed germination percentage (GP) of the plant was lower in the mass and it was 13% under constant temperature 25 degrees C with dark condition. The suitable temperatures for germination of the seeds were constant 30 degrees C or alternative 10-30 degrees C. To rupture or to remove seed pericarp could significantly increase GP and it was 49% and 47%, respectively. GP under pretreatment of seed soaked in 98% H2SO4 for 5 min was 32%. The pretreatments of seed soaked in 0.2% KNO3 for 24 h and seed kept at 10 degrees C for a week had no significantly effects on increasing GP. The seed germination was not sensitive to light condition. The hardness of the seeds was mainly responsible for the seed dormancy and low germination rate. The GP of S. chamaejasme seeds in the soil seed bank was higher than that gathered in the immediate year. Based on the comprehensive analysis with the lower GP and the results of field observation, it was concluded that S. chamaejasme seeds did not germinate every year in nature, and chance of population regeneration was random or periodic.

Germination↗

PubMed2004

[Study on configuration fabric and germinative conditions of Salvia miltiorrhizy seeds].

OBJECTIVE: To provide theoretic warrant and technical reference for Salvia miltiorrhizr standardization planting, by carrying out various systemic studies such as observation of seeds configuration fabric, idiosyncrasy of water absorption and groping germinating conditions. METHOD: In the study of configuration fabric, seeds were observed and taken photos by scanning electronic microscope, and heft method was used for measuring changes of water absorption velocity and dehydration velocity. Seeds germination conditions were probed into under the national test regulations for crop seeds and related prescription from international standards. RESULT: (1) There was a layer of slime about 10-20 microm thickness covering epicarp of Danshen seeds. The slime formed as diamond meshwork (reseau) and the weight of it was 8%-10% of total seeds weight. (2) The speed of water absorption of seeds was extremely rapid. The weight of seeds could increase above 10 times as original while the dehydration velocity was quite low. (3) The optimal temperature for the seeds germination is around 25 degrees C, and the germination rate of the new seeds gained yearly was above 75%, but the rate would decrease sharply as years went by. It was also found that the seeds germination power and exponent of vigor were quite high under the temperature transformation between 23 degrees C, 28 degrees C. Such treatments as pre-cool, PEG treatment and infusing with GA3 could increase the rate of seeds germination capacity obviously.

Germination↗

PubMed2006

[Seed population dynamics and germination characteristics of Eupatorium adenophorum].

With bare land, farmland, and masson pine forestland in the Eupatorium adenophorum- invaded area of Dechang County, Sichuan Province as test habitats, this paper studied the seed population dynamics of E. adenophorum at the levels of seed rain and seed bank, and its seed germination characteristics under effects of light and soil medium. The results showed that in the three habitats, the seed population of E. adenophorum only existed from March to June, and reached its peak by the end of April. The annual seed rainfall in bare land habitat amounted to 2.4 x 10(5) individuals per square meter, and all the seeds were distributed in the soil layer above 2 cm. The thousand seed weight and seed activity of E. adenophorum in bare land habitat were significantly higher than those in another two habitats. No active seed was found in the three habitats by the first ten days of July. Under artificial light condition, full light had some inhibitory effects on seed germination, while 28% of full light gave the highest germination rate. Sandy loam soil was more favorable for the seed germination, while in un-reclaimed red soil, both the germination velocity and germination rate were the lowest.

Ageratina↗

PubMed2006

[Effects of Larix gmelini aqueous extracts on seed germination and seedling growth of Juglans mandshurica].

In this study, Juglans mandshurica seeds were drenched in different concentrations (12.5, 25, 50 and 100 g x kg(-1)) aqueous extracts from adult Larix gmelini root, bark, branch and leaf for one week, and cultured in greenhouse in mid-April, 2004. The germination rate and germination index were calculated 18 days later, and the seedling's height and collar diameter were measured on August 1st. The results suggested that 25 g x kg(-1) root and 12.5 g x kg(-1) bark and branch aqueous extracts of L. gmelini could significantly increase the seed germination rate and germination index of J. mandshurica (P < 0.05), and 12.5 g x kg(-1) root and bark aqueous extracts could significantly increase the seedling height and collar diameter (P < 0.05). High concentrations of L. gmelini leaf aqueous extract could significantly promote the seed germination and seedling growth of J. mandshurica, but the promotion effect decreased gradually with decreasing concentration of leaf aqueous extract. The promotion of L. gmelini aqueous extracts to J. mandshurica seed germination and seedling growth might be related to the allelopathy between these two tree species.

Germination↗

PubMed2006

[Studies on germination characteristics of Platycodon grandiflorum seed].

OBJECTIVE: To find out the optimal condition for the germination by studying the effects of light, temperature, seed soaking and cultivation condition on Platycodon grandiflourm, and offer the basis for standardized culture of P. grandflorum. METHOD: The rate of water absorption of the seed was determined. The germination of P. grandiflorum seed was tested under following conditions: treatments under different temperature (10,15,20,25,30 degrees C), light treatments (light and dark), seed soaking time (12,24,36 h) and different germination cultivation conditions (on filter paper, between filter paper, between gauze,on gauze). RESULT: The water absorption of the seeds reached the maximal 120% within 36 h at 25 degrees C. The time of seeds soaking had limited effect on the germination of the seed, while temperature and light condition showed significant effects on the germination. CONCLUSION: The optimal condition for the germination of the seed of P. grandiflorum is as follow:seed soaking for 12 h, and 25 degrees C underlight.

Germination↗

PubMed2001

Expression of connexin43 in mouse Leydig, Sertoli, and germinal cells at different stages of postnatal development.

Connexin 43 (Cx43) is the most abundant and ubiquitously distributed gap junction protein in testicular cells. Lack of Cx43 expression results in male infertility. We investigated whether Cx43 is expressed and regulated in Leydig, Sertoli and germinal cells at different stages of postnatal development. Cx43 was detected using three different antibodies shown by immunoblotting to be highly specific. At different postnatal ages Cx43 localization was compared in serial or double labeled testicular cryosections with immunocytochemical distribution of steroidogenic enzyme, 3 betahydroxysteroid-dehydrogenase (3betaHSD), Mullerian inhibitory hormone (MIH), and germinal nuclear cell antigen (GNCA1), which are specific markers of interstitial Leydig, Sertoli and germinal cells, respectively. In the interstitium, round cell clumps (RCC) with lipid droplets positive for 3betaHSD and Cx43 were frequently found at intertubular areas at birth and Cx43 was mainly localized at cell membrane appositions. From day 3, the number and size of 3betaHSD-positive RCC started to decrease, and reached a minimum at 7-14 dpp; Cx43 expressed by them is progressively downregulated. From day 21 an increase in the size and number of RCC positive for Cx43 and 3betaHSD was found that continued at 24, 26 and 28 days and reached a maximum at 35 and 60 dpp. Biphasic expression of interstitial Cx43 and 3betaHSD was also found to be positively and temporally correlated with fluctuations in intratesticular testosterone content at all ages studied. In the seminiferous cord (SC), Cx43 was expressed at birth between adjacent Sertoli cells (MIH positive) localized at the periphery, as well as in their cytoplasm projections that surround centrally localized gonocytes. From days 3 to 7, Cx43 labeling increased in Sertoli cells mainly at their apical border. At day 14, Cx43 distribution in Sertoli cells changed from apical to basal in parallel to migration of germinal (GNCA1-positive) cells from the periphery to the center of the SC. At all these ages, Cx43 was also localized at cell borders between Sertoli and germinal cells. In conclusion, this study demonstrates that Cx43 in Leydig cells is regulated during postnatal development in an age and functional dependent manner. In the tubule, it is demonstrated that Cx43 is modulated in Sertoli cells during the neonatal and prepubertal period. We also provide evidence for the first time that Cx43-gap junctions communicate between Sertoli and germinal cells before and during the first wave of spermatogenesis.

3-Hydroxysteroid Dehydrogenases↗

PubMed1988

Characterization of genes that are developmentally regulated during Dictyostelium discoideum spore germination.

Similar to other stages in Dictyostelium development, spore germination is a particularly suitable model for studying the regulation of gene expression, because developmentally regulated changes in both protein and mRNA synthesis occur during the transition from dormant spore to amoeba. Spores are constitutively dormant and must be activated to germinate. Under the proper environmental conditions, spores germinate in a highly synchronous manner to give rise to individual amoebae that can then enter the vegetative growth phase. Protein synthesis is developmentally regulated during this process. Because protein synthesis is transcriptionally controlled during spore germination, the respective genes must be developmentally transcribed, and these can be isolated and analyzed. Three cDNA clones specific for mRNA developmentally regulated during spore germination have been characterized and used as probes to study mRNA accumulation and decay during spore germination. Because we are interested in defining the sequences of developmentally regulated genes that may relate to their regulation of transcription, we have sequenced the cDNAs and have isolated and sequenced their respective genomic clones. The sequences of the three gene families, their genomic organization, and their special structural features are described.

Amino Acid Sequence↗

PubMed1994

Development of antibody diversity in single germinal centers: selective expansion of high-affinity variants.

In a T cell-dependent immune response the microenvironment of the germinal center plays a crucial role in the affinity maturation of the antigen-specific, immunoglobulins. In order to look at the development of antibody diversity we have isolated single germinal centers and sequenced light chains characteristic of 2-phenyl-oxazolone (phOx)-specific antibodies. Fourteen days after immunization we can demonstrate various stages of intraclonal diversity. There are germinal centers where B cells are practically unmutated, suggesting that in these cases a substantial clonal expansion has taken place prior to the activation of the hypermutation mechanism. In other germinal centers, sequences with a low number of randomly distributed somatic mutations were observed, indicating that these changes have been introduced recently and/or that they fail to generate high-affinity variants and hence provide no basis for affinity selection. Finally, germinal centers are found in which practically all sequences carry the amino acid substitutions characteristic of the high affinity phOx antibodies. In these latter cases the high-affinity variants have been preferentially expanded. We conclude that affinity selection is a process that operates right from the beginning of germinal center development. Those B cells with a relative high affinity for the antigen gain a proliferative advantage over other cells and will dominate the response and these are the cells which will be selected to differentiate into memory cells.

Amino Acid Sequence↗

PubMed1979

[Interferometric studies of the dynamics of hydration and dry matter content during light-dependent germination of the Anabaena variabilis Kützing akinetes].

Calculations following interference-microscopical measurements performed on akinetes (A), heterocyts (H), and "vegetative" cells (F) of the Cyanobacterium (blue-green alga) Anabaena variabilis resulted in significant higher values of mean absolute dry matter content of the akinetes (2.06 . 10(-10) g; as compared to 0.46 . 10(-10) g and 0.31 . 10(-10) g for H and F, respectively). tthe water content of these resting cells (63%) was significantly lower than in the other two types of cells (H: 85%, F: 77%). Light exposition of the akinetes in fresh nutrition medium (i. e., conditions allowing germination within 30--50 h) resulted in a decrease of the relative dry matter content so that already in the period preceding the outgrowth of the germling the water content of the vegetative cells was achieved. Simultaneously their volume increased by the uptake of water; whereas the absolute content of dry matter remained constant or was even temporarily diminished during the first period. Only in the second period the values increased in some cases and then remained constant up to germination. The increased dry matter content, however, was not a precondition necessary for the germination of the akinetes. In darkness under otherwise unaltered conditions the values remained unchanged or, after a light period, came back to the initial level. The results demonstrate that formation and germination of the resting cells of Cyanobacteria as well are connected with an alteration in the hydratation level, i. e., in cells which continuously are kept under water saturated conditions. This increase by hydratation during the germination period is, as the germination process itself, strictly controlled by light.

Cyanobacteria↗

PubMed1998

Induction of a germination specific, low molecular weight, acid phosphatase isozyme with specific phosphotyrosine phosphatase activity in lentil (Lens esculenta) seeds.

A germination specific isozyme of acid phosphatase (EC 3.1.3.2) hydrolysing O-phospho-L-Tyrosine, pH optima 5.5 is induced in lentil seeds. When seeds at 0 h, 24 h and 36 h of germination are electrophorezed, native PAGE on specific enzyme staining shows several constitutive isozymes of acid phosphatases. At 48 h, an isozyme is induced which gradually decreases and then disappears at 108 h of germination. The short lived, induced isozyme is present in the embryo and seed-coat but not in the plumule and the radical. Induction of this isozyme is inhibited by cycloheximide and actinomycin-D and increased by plant growth regulators such as heteroauxin and gibbrellic acid treatment during germination. The induced isozyme is a single 30 kD polypeptide, with subunit molecular mass of 25 kD, shows activity for O-phospho-L-Tyrosine. It is strongly inhibited by vanadate (microM), molybdate, tungustate as also by iodoacetate, p-chloromercuribenzoate and diethylpyrocarbonate. This study shows for the first time that the germination induced low molecular weight Acid phosphatase is a Tyrosine phosphatase super family class IV enzyme, having a role in cellular differentiation and development during seed germination.

Acid Phosphatase↗

PubMed1998

Changes in cyclin B during oocyte maturation and early embryonic cell cycle in the newt, Cynops pyrrhogaster: requirement of germinal vesicle for MPF activation.

When full-grown oocytes of the newt Cynops pyrrhogaster were treated with progesterone in O-R2 solution containing antibiotics, approximately 85% of the oocytes completed meiosis synchronously. Maturation-promoting factor (MPF) activity appeared just before germinal vesicle breakdown (GVBD) and the oocytes maintained high MPF activity throughout metaphase I and metaphase II of meiosis. A slight decrease of MPF activity was observed at the first polar body emission. The distribution of cyclin B1 was investigated with anti-cyclin B1 antibody. No cyclin B1 was found in the oocytes before progesterone treatment. Cyclin B1 appeared in the cortex of animal hemispheres, especially around and inside germinal vesicle just before GVBD. A large amount of cyclin B1 accumulated at metaphase I, approximately half disappeared at the first polar body emission, and then cyclin B1 accumulated again at metaphase II. An inactive form of cdc2 kinase was observed in both the germinal vesicles and the oocyte cytoplasm, while an active form appeared at the M phase. No MPF was observed in the oocytes from which the germinal vesicle had been removed. A cdk7-like molecule was localized in the germinal vesicle, but not in oocyte cytoplasm, indicating that inactive cdc2 kinase associated with cyclin B1 derived from cytoplasm is activated by phosphorylation in the germinal vesicle. The changes in the amount of cyclin B1 were synchronous with the first cell cycle after fertilization. Cyclin B1 was primarily localized in the cortex of the animal hemisphere. A shift in band mobility upon electrophoresis of cyclin B1 was observed from samples taken during the cell cycle; this shift was probably due to the protein's phosphorylation state.

Animals↗

PubMed1979

RNA synthesis during spore germination in Bacillus subtilis.

We have analyzed the RNA synthesized during spore germination in Bacillus subtilis. Early in germination there is little incorporation of [3H]uridine into RNA. A large increase in incorporation into RNA was found at 45--60 min into germination which was in part due to increases in the specific activity of the UTP pool. When corrected for specific activity changes, the instantaneous rate of RNA synthesis showed a seven to tenfold increase between 30 and 45 min of germination. Polyacrylamide gel electrophoresis studies showed that the RNA synthesized during germination appeared very similar to the RNA made during vegetative growth. DNA-RNA hybridization studies indicated that mRNA and rRNA were synthesized throughout germination. Their relative proportions remained constant and were very similar to the composition of RNA synthesized during vegetative growth.

Bacillus subtilis↗

PubMed1994

Changes in the carbohydrates and nitrogenous components during germination of proso millet, Panicum miliaceum.

Since germination has been found to increase the nutritive qualities of grains, proso millet, a minor millet, was allowed to germinate for 1-7 days and analysed for protein fractions, free amino acids, lysine, tryptophan, methionine, non-protein nitrogen, starch, and sugars. Overnight soaking and germination up to 7 days significantly increased the free amino acids and total sugars while the content of dry weight and starch decreased. Increases in albumin and globulin and large decreases in prolamin accompanied sprouting. The percent protein in germinated grains was higher than in the initial grain as a result of dry matter loss during germination. Further, there was an increase in lysine, tryptophan and non-protein nitrogen contents during germination. No change was noticed in methionine content.

Carbohydrate Metabolism↗

PubMed1994

The degradation of lectins, phaseolin and trypsin inhibitors during germination of white kidney beans, Phaseolus vulgaris L.

White kidney beans (Phaseolus vulgaris), cv Processor, contain a relatively high content of phaseolin (storage protein), lectins and a special group of glycoproteins as well as a considerable amount of protein-type trypsin inhibitors. Protein digestion of raw 'Processor' beans in monogastrics, for example pigs, is disturbed by poorly digested, phaseolin lectins, which can bind to carbohydrates in brush border membranes of the small intestinal epithelium, and trypsin inhibitors. The effect of the germination of white kidney beans on lectins, phaseolin and trypsin inhibitors was studied in order to achieve a degradation of lectins, phaseolin and trypsin inhibitors and an increase of in vitro enzymatic hydrolysis of the protein of bean flour. Therefore, whole bean extracts were examined throughout a germination period of up to seven days for their lectin and phaseolin pattern, lectin content, binding capacities of functional lectins towards brush border membranes and trypsin inhibitor content. In addition the in vitro enzymatic hydrolysis by pepsin and pancreatin of the protein from flours of (un)germinated white kidney beans was studied. SDS-PAGE demonstrated a degradation of E-lectins and a disappearance of L-lectins and phaseolin during germination. Results indicated a decrease of the lectin content by 85%, a loss of binding capacities of functional lectins towards brush border membranes by 91%, and a decrease of trypsin inhibitors by 76%, in bean flour after germination for seven days. A maximum in in vitro enzymatic hydrolysis of protein from bean flour was already established after germination for half a day.

Animals↗

PubMed1990

Irradiation and germination effects on phytate, protein and amino acids of soybean.

Influence of irradiation (0.05-0.20 kGy) and germination (24-120 hours) in distilled and tap water on phytate, protein and amino acids of soybean, was studied. Phytate values significantly decreased with increasing germination period and irradiation dose (P less than 0.01). Irradiation independently decreased the original phytate (212.0 mg/100 g) to a range value of 205.0-190.0 mg/100 g depending upon dose level. Germination of unirradiated seeds for 120 hours in distilled and tap water lowered the phytate to 55.0 and 94.9 mg/100 g (74.1 and 55.2% reduction) respectively. Maximum destruction of phytate to levels of 20.5 and 50.9 mg/100 g (90.3 and 76.0% reduction) occurred during germination of 0.20 kGy samples for 120 hours in distilled and tap water respectively. Total protein content significantly increased during germination (P less than 0.05) and the increase was more in tap than distilled water. Germination for 120 hours of untreated seeds in tap water increased the essential and decreased non-essential amino acids while in the 0.10 kGy sample, increases in both cases were observed.

Amino Acids↗

PubMed1988

[Effect of germination on protein quality of wheat and mung beans--studies of nitrogen balance in growing rats].

The bioavailability of limiting amino acids (lysine, cystine and methionine), which are formed during the germination of wheat and mung beans, was assessed in nitrogen balance trials on growing rats. In addition, the influence of heat treatment on the protein nutritional value of wheat and mung beans was determined. Compared to ungerminated wheat, net protein utilization (NPU) and biological value (BV) increased from 30% and 36% to 41% and 52%, respectively. Apparent protein digestibility (PD) decreased from 82% to 79% during 4 day germination. Heat treatment improved PD from 82% to 85% in ungerminated wheat, but not during germination. NPU and BV were not changed by heat treatment. Feeding germinated mung beans caused a markedly reduced feed intake by the animals, which made it impossible to evaluate changes in protein nutritional value during germination. Heat treatment of ungerminated mung beans improved PD, NPU and BV from 77%, 38% and 49% to 81%, 48% and 60%, respectively. The results indicate that the amino acids, in particular lysine, which are formed in germinating wheat, are available to the rat. Heat treatment will improve considerably the protein nutritional value of ungerminated mung beans.

Animals↗

PubMed1992

Protein synthesis during germination of heterothallic yeast ascospores.

Protein synthesis during ascospore germination of the heterothallic Saccharomyces cerevisiae strain AP-3 was investigated. Protein synthesis in the germinating ascospores appeared to begin approximately 20 min following glucose initiation. Since RNA synthesis did not start until approximately 70 min after the onset of germination, strain AP-3 ascospores must contain RNA which is ready for immediate translation. Both trehalase and glyceraldehyde-3-phosphate dehydrogenase activities were found to be affected by the onset of germination. Trehalase activity was found to increase severalfold following 60 min of spore germination but remained relatively constant over the subsequent 120 min examined. Dehydrogenase activity was not detectable in AP-3 ascospores but was measurable in germinating ascospores.

Fungal Proteins↗