Germination Of Cotton Seeds Research Articles

Metabolism of carbohydrate and lipid reserves in germinated cotton seeds

Utilization of reserve lipid and carbohydrates during germination (0-12 h) and postgerminative growth (12-48 h) was studied in cotton (Gossypium hirsutum L.) seedlings. Raffinose and stachyose were utilized during the germination period and early growth; mobilization was associated with α-galactosidase (EC 3.2.1.22) activity. Results from pulse-chase experiments with [(3)H]raffinose supplied exogenously to 4-h soaked seeds indicated that raffinose-derived catabolites contributed to the coincident increase in cotyledon sucrose and starch, and to the small increase in axis dry weight. Starch appears to be an alternative sink for end products of hydrolysis of reserve carbohydrates prior to the onset of rapid axis growth and cotyledon expansion. Mobilization of neutral lipid commenced at about 16 h after soaking, concomitant with development of key glyoxylate-cycle and other gluconeogenesis-related enzyme activities. Axis dry weight increased three-fold between 24 and 48 h. Results from pulse-chase (3 h, 16 h) experiments in which [2-(14)C]acetate was supplied to cotyledons of intact 22-h-old seedlings showed that acetate-derived metabolites were not transported exclusively to the axes, but were partitioned between axes and cotyledons. Only 27% of total incorporated radioactivity was recovered in axes following the chase, 18% was evolved as CO2, and the rest was recovered in water-soluble substances (20%) and polymers (31%) within the cotyledons. Of the polymers, 55% of the activity was in polysaccharides (Starch, pectic substances, hemicellulose, cellulose), 25% in protein, and 20% in unidentified neutral and acidic compounds. Considering these data, the amount of lipid mobilized, and various routes by which supplied [2-(14)C]acetate could be metabolized, it appears that lipidderived compounds contribute only 25-40% of axis dry-weight gain. Lipid-derived substances retained in the cotyledons likely are utilized for expansion and differentiation of the cotyledons into photosynthetic organs.

Nucleic Acids and Protein Metabolic Changes During Germination of Cotton Seed

Summary Gibberellic acid (GA 3 ) treatments of cotton seeds induced the synthesis of RNA, DNA and protein in the embryonic axis during the period of germination. In cotyledons of the same GA 3 -pretreated seeds, the RNA content was lower than in the controls, while the DNA content was increased at the beginning of germination. However, GA 3 treatments did not affect the content of cotyledonary protein. Indole acetic acid (IAA) at low concentration of 10 mg · l -1 resulted in a slight increase in the amount of RNA, DNA and protein synthesized in the axis, while at the higher concentrations of 50 and 100 mg · l -1 the RNA, DNA and protein synthesis were inhibited. In cotyledons, the RNA content was markedly higher than in the control during the first 48 h of germination when IAA was applied at 10 mg · l -1 . Also, the rate of protein depletion from the cotyledons decreased with increasing IAA concentrations, while the content of cotyledonary DNA was not significantly affected by IAA treatments. Coumarin at the lowest concentration used (1 mg · l -1 ) induced the synthesis of RNA, DNA and protein in the embryonic axis, but increasing the concentration of coumarin to 100 mg · l -1 resulted in a reverse effect of inhibition during the period of germination. In cotyledons, a high concentration of coumarin markedly decreased the rate of RNA and protein degradation during the germination period.

Increase in β-N-Acetylglucosaminidase Activity during Germination of Cotton Seeds

A marked increase in beta-acetylglucosaminidase (2-acetamido-2-deoxy-beta-d-glucoside acetamidodeoxyglucohydrolase, EC 3.2.1.30) activity was observed in the germinating cotyledon of cotton seeds. The enzyme was isolated from cotton seedlings and purified to study its physiological function in the germination of cotton seeds. The purification procedure involves ammonium sulfate fractionation, ion-exchange chromatography, gel filtrations, and concanavalin A-Sepharose 4B chromatography, and the purified beta-N-acetylglucosaminidase was shown to be homogeneous by disc electrophoresis. The molecular weight was estimated to be about 125,000 by gel filtration. The enzyme hydrolyzed both p-nitrophenyl-N-acetyl-beta-d-glucosamine and p-nitrophenyl-N-acetyl-beta-d-galactosamine. When p-nitrophenyl-N-acetyl-beta-d-glucosamine was used as substrate, K(m) and V(max) were 0.625 nanomolar and 228 moles per minute per milligram, respectively, and optimum activity was at pH 5.6. The enzyme liberated beta-linked N-acetyl-glucosamine from chitin, ovalbumin, and pronase-digested wheat germ lectin.

Studies on Azotobacter chroococcum: II. Effect of Azotobacter chroococcum on germination of seeds of agricultural crops

Summary The effect of strains of A. chroococcum on the germination of seeds of cotton, wheat and maize plants has been studied under three different conditions Stimulatory effect of A. chroococcum varied with the strains and the conditions under which seed germination was tested. Wheat and cotton seed germination was better in sterile petri-plates but large seeds of maize had shown better germination in sterile sand cultures. Use of homologous strains of A. chroococcum like W-5 for wheat, C-2 for cotton and M-2 for maize seed inoculations improved germination of seeds of respective crops.

Effects of Premature Defoliation and Plant Kill on Germination of Cottonseed1

AbstractPerformance data on cottonseed (Gossypium hirsutum L.) harvested from plants following premature defoliation and premature plant kill are limited. The objective of this study was to determine the effects of premature defoliation following adverse weather, hand defoliation, and premature plant kill (plants cut off at the soil line and dried rapidly in the greenhouse) at different dates in the fall on germination of cottonseed. The seed were stored for several weeks in the laboratory at about 30% relative humidity and 21 C before they were germinated at alternating 20 to 30 C and at a constant 18 C. Means for germination percentage, germination rate index (GRI), and coefficient of velocity of germination (CVG) were separated by Duncan's multiple range test. Reduced germination and GRI were obtained with seed harvest from plants that set fruiting following late season irrigation, premature defoliation following low temperatures, leaf removal by hand, and prematurely killed in September. Premature plant kill in October increased germination when compared to 50 and 100% leaf removal by hand and the check (no leaves removed). Germination was similar for seed harvested from plants with 50% leaf removal and the check. Removal of all leaves had the most adverse effect on the performance of cottonseed. The lowest CVG was obtained from plants left intact in the field. Seed from a determinant cultivar appeared to be affected less than seed from an indeterminant one.

Changes in Enzyme Levels of EMP and Pentose Phosphate Pathways during Germination of Cottonseed

Changes in the levels of key enzymes in the two carbohydrate oxidative pathways were studied in cotyledons and radicles of germinating cottonseed. Prior to radicle emergence, PFK activity exceeded G6P dehydrogenase activity. Following radicle emergence, G6P dehydrogenase activity increased more than twofold, whereas PFK activity remained the same in cotyledons but apparently decreased in the radicles. The seemingly decreased levels of the EMP enzymes in radicles were due to a dilution of protein content during elongation. Enzymes of the EMP pathway were demonstrated only in radicle tips, while enzymes of the pentose pathway were demonstrable in both tips and elongating segments. We suggest that during the initial phases of germination, especially when oxygen diffusion may be restricted by the intact testa, the early and high requirement for ATP is met by substrate level phosphorylation from enhanced EMP activity. Differentiation in both elongating radicles and cotyledons, which in cotton become photosynth...

Amino Acid Composition of Germinating Cotton Seeds

Total and free amino acid composition of germinating cotton seeds (Gossypium hirsutum L.) was determined. The germinating seeds were separated into cotyledon and developing axis fractions daily and the composition of each tissue was summed to get the whole seed composition. By separating the developing seeds into these two tissue fractions, and determining total and free amino acids, a balance sheet was developed for each amino acid. This technique allowed changes in distribution with time of each amino acid to be followed in each tissue. Data for total content and amount in protein of each amino acid are presented. Asparagine increased in the whole seed, and most of this increase was found in the free pool of the developing axis. Other amino acids (e.g. arginine, glutamic acid) increased in the free pool but showed an over-all decrease, indicating that they were being metabolized. Amino acid contents of storage and nonstorage protein isolates were determined.

Fungicide Application to Cottonseed Using Methylene Chloride Carrier1

A method is described for quantitative application of chemicals to cottonseed (Gossypium hirsutum L.), using methylene chloride as a carrier. The objective of this study was to compare the performance of fungicides applied with methylene chloride with those of fungicides applied in wettable powder formulations in field studies. Nonsystemic fungicides used were PCNB (pentachloronitrobenzene) and ETMT [5,ethoxy‐3‐(trichloromethyl)‐l,2, 4‐thiadiazolel. Systemic fungicides used were chloroneb (l,4‐dicholoro‐2,5‐dimethoxybenzene) and carboxin (5,6‐ dihydro‐2‐methyl‐1,4‐oxathiin‐3‐carboxanilide). Germination of cottonseed was reduced by methylene chloride, apparently because it killed mechanically damaged seeds. This reduction was reflected in field studies where stands from seeds treated with fungicides in the solvent averaged 6% less than stands from seeds treated with fungicides in wettable powder formulations. Solvent‐applied fungicides, both systemic and nonsystemic, gave no more seed protection than wettable powders.

Evaluation of Seed Treatments to Enhance Pima Cotton Seedling Emergence1

AbstractPrevious research has shown that germination of cottonseed (Gossypium spp.) can be improved during low temperature by treating seed with gibberellic acid (GA3), kinetin, or by elevating the seed moisture level. The work reported here was conducted to evaluate these seed treatments as aids to improving seed germination of G. barbadense L. (‘Pima S‐4’) and to determine if they enhance seedling emergence in fields with low soil temperatures. Soaking seed in water for 6 hours before chilling at 5 C significantly reduced visual chilling injury. Both kinetin and GA had little effect on % germination, but vigor of germinating seed was increased in the laboratory when seed were soaked for 3 hours in 0.1 or 1.0 mg/liter kinetin, or 100 or 500 mg/liter GA.When similar seed treatments were evaluated in several field plantings with low soil temperatures, neither chemical improved the number of seedlings emerged or the time required for emergence. GA at the level that promoted seed vigor in the laboratory resulted in greatly reduced emergence because of spindly growth. Soaking seed in water before planting generally reduced emergence with the degee of reduction directly related to length of soaking. Seed that were soaked for 3 hours showed abnormal development of cotyledons and reduced dry wt. compared to nonsoaked seed. Thus these seed treatments cannot be recommended as aids to enhance Pima cotton seedlings emergence.

Polyadenylylation of Stored mRNA in Cotton Seed Germination

This chapter discusses that much of the mRNA used by germinating cotton cotyledons in the first several days of germination is transcribed in embryogenesis but not used until germination begins. It considers the body of mRNA to code for proteins unique to the germination process rather than representing mRNA functioning in embryogenesis and carried over undergraded into germination. In fact, a specific enzyme, unique to germination, arises from this “stored” mRNA. The chapter attempts to determine by several methods whether preexisting mRNA is polyadenylylated during the first 24 hours of germination. The first of these involved measuring the relative extent of incorporation of [ 32 P] phosphate and [2- 3 H] adenosine into the mRNA portion and poly (A) portion of mRNA (A,) of cotyledons during the hours 10–20 of germination. This was done by isolating mRNA (A n ) from extracts of the tissue on oligo( dT)-cellulose columns using standard techniques. The mRNA portion of the molecules was digested with ribonucleases A and T 1 and the poly (A) portion was recovered by oligo (dT)-cellulose chromatography. The chapter summarizes that the values obtained in the experiments for the true mass-average mRNA chain-length and for the relative amounts of preexisting and newly synthesized mRNA that is polyadenylylated during the first day of germination. Although there is considerable variation in the latter values depending on the method of evaluation used, in every case the polyadenylylation of preexisting RNA is suggested.

Inhibition of Cottonseed Germination with Abscisic Acid and Its Reversal

Germination of cottonseed (Gossypium hirsutum L.) was inhibited by abscisic acid. Inhibition was greater when seeds were soaked in abscisic acid for 5 hours and dried prior to germination than when abscisic acid was applied in the germination medium. (2-Chloroethyl)phosphonic acid, gibberellic acid, and kinetin partially overcame the inhibitory action of abscisic acid. Combinations of (2-chloroethyl)phosphonic acid with gibberellic acid or kinetin were more effective than the individual substances. Germination also was partially restored by removal of seed coats. Fusicoccin completely restored germination of abscisic acidtreated seeds.

The developmental biochemistry of cotton seed embryogenesis and germination VI. Levels of cytosol and chloroplast aminoacyl-tRNA synthetases during cotyledon development

The separation of isotransferring aminoacyl-tRNA synthetase activities (amino acid : tRNA ligases, EC 6.1.1.x) for several amino acids extracted from tissues of embryonic and germinating cotton seeds was carried out by DEAE-cellulose column chromatography. Evidence was obtained that the separated activities represent discrete enzymes, and could be defined as cytosol or chloroplast enzymes by several criteria. The levels of the cytosol enzymes per cell were found to be constant in germinated and ungerminated cotyledons. Chloroplast enzymes were found to be present in immature embryonic cotyledons and in roots at constant levels relative to the cytosol enzymes, but found to increase markedly in germinating cotyledons. This increase takes place to the same extent in etiolated cotyledons as in greened cotyledons indicating that the chloroplast synthetase increase is analogous to the simultaneous increase in chloroplast tRNA and rRNA which also is not light dependent. The separated cytosol and chloroplast enzymes show varying degrees of specificity for isoaccepting tRNA species from homologous and heterologous sources.

Storage and metabolism of poly(adenylic acid)-mRNA in germinating cotton seeds.

When the RNA from both the nucleus and polysomes of germinated cotton seeds were fractionated on poly(U)-cellulose columns it was found that both contained poly(A)-RNA. In ungerminated seeds most of the poly(A)-RNA is located in the nucleus of the cell. 3'-Deoxyadenosine was found to inhibit the synthesis of both nuclear and polysomal poly(A) by 75% in germinated seeds, but had little or no effect on protein synthesis during the first 6 hr of germination. After this time 3'-deoxyadenosine had a pronounced inhibitory effect on protein synthesis presumably due to the inhibition of poly(A) addition to newly synthesized mRNA.

Distribution of fatty acids during germination of cottonseeds.

Gas chromatographic determination of the fatty acids in the seeds of cottonseed (Gossypium sp.) showed linoleic, palmitic, oleic, and stearic acids, with linoleic acid being the major component. Changes in the composition of fatty acids during various stages of germination were measured in the cotyledons and in the roots. A decrease in the content of all the fatty acids and an 8-fold increase in the moisture content of the cotyledons were observed during the 10 days of germination. There were no significant changes in the fatty acid contents of the roots with the exception of those in linoleic acid which increased by 50 percent during 4-10 days of germination. The possible significance of these changes is discussed.

Treatment of cotton seeds for germination

Effects of H2SO4, H2O2, C2H5OH and of acetone on germination of cotton seeds and on the growth of seedling root were studied under laboratory conditions. H2SO4 or H2O2 hastened germination but decreased the ultimate number of seeds germinated. Higher temperature (27°C) hastened germination and increased the number of seeds germinated. Root length remained unaffected by treatments at room temperature while H2SO4 or H2SO4/H2O2 substantially decreased it at 27°C.

Effect of Pregermination Treatments on Germination and Growth of Cottonseed at Suboptimal Temperatures1

Various pregermination treatments were used to determine their effects on germination of cottonseed (Gossypium barbademe L.) at suboptimum temperatures and to determine whether chilling injury was reduced by these treatments.‘Pima S‐4’ cottonseed were preconditioned in water and gibbercllic acid (10‐3M) at 10 and 30 C or in adenosine‐ 3′:5′.cyclic monophosphate( cyclic AMP,10‐4M) at 30 C, or were hot‐water‐treated at 70 C for 5 rain. After being preconditioned, seed were chilled for 24 hours at 5 C in water. Seed were germinated over a temperature range of 15.5 to 30 C for 7 days on a thermogradient plate. Germination counts were made daily. The speed and percent of germination were higher for seed preconditioned at 30 C than at 10 C. Hot‐water treatment reduced the sensitivity of seed to gibberellic acid and reduced germination at all temperatures. Chilling injury was reduced by preconditioning in either water, gibberellic acid, or cyclic AMP. Our data suggest that satisfactory cotton stands may be obtained at suboptimum temperatures (below 31 C) by elevating seed moisture and/or treating with a growth regulator prior to planting.

Pyruvate Kinase, a Possible Regulatory Enzyme in Higher Plants

A number of plant species were examined for the presence of pyruvate kinase (pyruvate-ATP phosphotransferase, EC 2.7.1.40), and of a phosphatase activity which hydrolyzes phosphoenolpyruvate. Of those examined, only cotton (Gossypium sp. L.) seeds were found to be sufficiently free of the phosphatase to permit a kinetic study of pyruvate kinase.During germination of cotton seeds, pyruvate kinase activity rises for the first 3 days, after which it falls back to its original level. This developmental pattern is characteristic of enzymes involved in the conversion of fat into carbohydrate in fatstoring seeds. The phosphatase also rose rapidly during germination, which precluded the use of extracts from seedlings in the study of pyruvate kinase. No evidence was found for the presence of more than one pyruvate kinase in cotton seedlings.In crude extracts from ungerminated seeds, the enzyme shows slight deviations from normal kinetics with respect to phosphoenolpyruvate, magnesium, and to a lesser extent, ADP. After partial purification of the enzyme by ion exchange chromatography, the enzyme shows normal kinetics. The enzyme is activated by AMP, and inhibited by both ATP and citrate, in both crude and partially purified preparations. It is suggested that cotton seed pyruvate kinase is a regulatory enzyme.

Lucerne Saponins as Inhibitors of Cotton Seed Germination

Lucerne Saponins as Inhibitors of Cotton Seed Germination

Influence of Low Temperature During Cottonseed Germination on Growth and Disease Susceptibility

Influence of Low Temperature During Cottonseed Germination on Growth and Disease Susceptibility

Effect of Delinting and of Genetical Factors on the Germination of Cotton Seeds at Low Temperatures1

Acid delinting improved and accelerated the germination of cotton seeds at low temperatures in tests conducted both in an incubator (at 12 C and 14 C) and in the field. All the cultivars of Gossypium hirsutum L. and G. barbadense L., tested in these experiments, exhibited this effect, even though seeds of the latter species were covered only by a negligible amount of fuzz. This indicates that acid delinting increases the permeability of the seedcoat.Water was absorbed by the fuzz during the first hours after planting, but later acid‐delinted seeds showed a higher rate of water absorption. The inheritance of the ability of cotton seeds to germinate at low temperatures is probably polygenic and primarily additive, with prominent maternal effects which are associated with characteristics of the seedcoat and the fuzz.