Germination Of Cotton Seeds Research Articles

Soaking in H2O2 regulates ABA biosynthesis and GA catabolism in germinating cotton seeds under salt stress

Exogenous H2O2 improves seed germination with the involvement of ABA and GA in a number of plant species but how it affects cotton seed germination under salinity stress is not well documented. In this study, we found that the marked inhibition of cotton seed germination under salinity stress was considerably alleviated by pretreatment with H2O2. Salt stress increased the ABA content by upregulating ABA biosynthesis genes, NCED2, NCED5 and NCED9 and downregulating the ABA catabolism gene, CYP707A2. It also decreased the GA content by increasing the expression of GA catabolism gene, GA2ox1 and decreasing that of the GA biosynthesis gene, GA20ox1 during germination. Pretreatment with H2O2 downregulated the ABA biosynthesis genes, NCED5 and NCED9, thereby decreasing the ABA content in germinating seeds. Concurrently, it increased the GA content by downregulating the GA catabolism gene, GA2ox1. These results suggest that pretreatment with H2O2 improved cotton seed germination by mediating the downregulation of ABA catabolism and GA biosynthesis under salt stress.

Effect of various sterilization procedures on the in vitro germination of cotton seeds

In vitro manipulations of cotton often require high-quality sterile seedlings as a source of hypocotyl and cotyledon explants for initiation of embryogenic cultures or embryo apexes for shoot production. Unfortunately, in vitro seed germination is often hindered if cotton seeds were collected from the open field and stored under improper conditions. In our case a limited supply of field-grown cotton seeds was received, which necessitated the development of a more effective surface sterilization protocol. Seeds from two accessions, designated as I and II, with very high contamination levels and lowered germination rate were used in this study. These seeds were treated with the most commonly used sterilizing agents, which included commercial bleach, chlorine gas and hydrogen peroxide. Additional steps such as soap-water washes (SW), 70 % ethanol (ETH) and plant preservative mixture rinses were also included in the sterilization procedures to improve the efficiency of tested protocols. Surface sterilized seeds were germinated on Linsmaier and Skoog medium and the percentage of contamination free and well-germinated seeds were recorded for each treatment. Seeds treated with hydrogen peroxide showed significant improvement in germination rate and level of contamination when compared to identical seeds treated with chlorine gas and commercial bleach. The most effective sterilization protocol for all genotypes tested consisted of SW wash followed by ETH rinse and H2O2 sterilization for 7 h. This protocol was successfully used to sterilize seeds of 55 cotton lines.

면실 종자의 발아억제를 위한 전처리 조건 연구

This research study was to develop methods for inhibiting the germination of cotton seeds. Germination rates after heating treatment at <TEX>$80^{\circ}C$</TEX> with 10, 20, 30, 40 min. were 9.3, 9.3, 5.3 and 1.3 percentage, respectively. Heat treatment over <TEX>$85^{\circ}C$</TEX> with 10 min. caused no germination of cotton seeds. Germination was significantly reduced with gamma rays treatment more than 10,000 gy, while the treatment within 2,000-8,000 gy induced less effects. Microwave processing for 30 seconds and 60 seconds inhibit the germination of cotton seed under 8 and 0%, respectively. As a physical treatment, rollmill milling with 1.5, 2, 2.5 mm gap inhibited any germination of cotton seeds. The optimum gap of roll-mill for processing physical cracking was below 51% of the thickness of seed.

Dibutyl Phthalate Pollution on Cotton Growth and Physiological Characteristics of Cotton

Because use of plastic in cotton field made a lot of dibutyl phthalate contaminants, they were introduced to the soil of cotton field. Through the germination of cotton seeds and cotton seedling physiological indicators will be measured to study the dibutyl phthalate on cotton growth and development impact. The results showed that different concentrations of n-butyl phthalate had some of the cotton seed germination inhibition, and with increasing concentrations its inhibition increased .But at low concentrations of dibutyl phthalate promoted seed germination. Dibutyl phthalate produced an effect on cotton SOD, POD and CAT activity, with increasing the concentration of DBP, SOD and CAT activity of cotton leaves began to increase subsequently reduce the phenomenon appears. MDA levels have been rising, cotton cell membrane damaged.

Influence ofVerticillium dahliaeInfested Peanut Residue on Wilt Development in Subsequent Cotton

Texas ranks first in cotton production in the United States and accounts for approximately 40% of the total production. Most of the cotton production is concentrated in the Texas High Plains where cotton and peanut are commonly grown in rotation. With peanut being a legume crop, farmers routinely leave residue on the soil surface to improve soil fertility; however,V. dahliaecan survive in the crop residue contributing inoculum to the soil. A microplot study was conducted to investigate the impact of peanut residue infested withV. dahliaeon subsequent microsclerotia density in soil and Verticillium wilt development in cotton. The effects of infested peanut residue rate on percent germination of cotton seeds and on wilt incidence were monitored in 2008 and 2009. In both years microplots were planted with a susceptible cotton cultivar, Stoneville (ST) 4554B2RF. Increasing infested peanut residue rate was positively correlated with wilt incidence in cotton and negatively correlated with germination of cotton seeds. Density of microsclerotia in the soil increased significantly with increasing rates of infested peanut residue over time. Results indicate infested peanut residue serve as a source ofV. dahliaeinoculum, and removing infested residue can reduce disease development in subsequent cotton crops.

Chilling Stress Accelerates Degradation of Seed Storage Protein and Photosynthetic Protein during Cotton Seed Germination

AbstractLow temperature is one of the major abiotic stresses limiting the productivity and geographical distribution of many important crops. To gain a better understanding of chilling stress responses in cotton (Gossypium hirsutum L.), we carried out a comparative proteomic analysis. Cotyledon proteins of 1‐week‐old cotton seedlings treated with or without chilling treatment at 4 °C were extracted, separated by a two‐dimensional gel electrophoresis and compared. Among 1500 protein spots reproducibly detected on each gel, 25 protein spots were down‐regulated and 29 were up‐regulated. Seven cotton proteins were identified by mass spectrometry analysis as beta‐globulin A precursor fragments. One was identified as a Rubisco large subunit fragment, providing evidence of both seed storage protein and photosynthetic protein destruction by chilling stress. The related physiological and biochemical analysis showed that there was a significant increase in endopeptidase activity and activated oxygen generation rate, and an obvious decrease in carboxylation efficiency and maximum net photosynthetic rate of cotton seedlings under chilling stress. Based on the above results, the degradation mechanisms of beta‐globulin and Rubisco under chilling stress were discussed. In conclusion, our study provides new insights into chilling‐stress responses in cotton and demonstrates the advantages of proteomic analysis.

Effect of methanol on phospholipid composition of germinating cotton seeds

The effect of methanol on the change of phospholipid composition of germinating cotton seeds was studied. It was shown that adding methanol to the germination medium caused the formation of the new phospholipid phosphatidylmethanol.

Potencial do uso da restrição hídrica em testes de sanidade de sementes de algodoeiro

Nos testes de sanidade, realizados por meio dos métodos de incubação em papel de filtro e em meio agarizado, a germinação rápida das sementes dificulta a identificação dos fungos e pode comprometer a validade desses métodos. Para impedir ou reduzir a germinação de sementes de espécies dicotiledôneas, o uso de 2,4-D (sal de sódio) tem sido a alternativa disponível havendo, no entanto, questionamentos sobre este composto por inúmeras razões, inclusive o aspecto toxicológico. Neste trabalho, o objetivo foi estudar a viabilidade do uso da restrição hídrica como recurso para reduzir a germinação das sementes em substituição ao 2,4-D. Foram utilizados os restritores hídricos manitol e Cloreto de sódio, nos potenciais -0,6, -0,8, -1,0 e -1,2 MPa, sendo avaliados seus efeitos sobre a germinação das sementes, comprimento de plântulas e crescimento micelial in vitro dos principais fungos associados a sementes de algodoeiro e seu desenvolvimento sobre as sementes no teste de incubação em papel de filtro. A restrição hídrica proporcionada pelos solutos e potenciais osmóticos testados foi capaz de reduzir a germinação e o comprimento das plântulas em níveis considerados satisfatórios para a análise sanitária de sementes de algodoeiro, além de não interferir na recuperação dos principais fungos sobre as sementes no teste de papel de filtro, revelando-se desta forma como uma alternativa eficaz em substituição ao uso do 2,4-D. O crescimento micelial dos fungos em meio agarizado foi reduzido nos potenciais osmóticos a partir de -0,6 MPa. A recuperação dos fungos fitopatogênicos através do teste de incubação em papel de filtro não foi afetada pelo método da restrição hídrica.

Properties of cotton inorganic pyrophosphatase

The activity of inorganic pyrophosphatase and pyrophosphate content were studied in developing and germinating cotton seeds. It was shown that the content of pyrophosphate in germinating seeds reached its maximum value after two days of their development, and the activity of inorganic pyrophosphatase, one day after the beginning of seed bud formation. The low pyrophosphatase activity of dormant seeds increased during their germination under open-ground conditions, reaching its maximum on day 6-7. Properties of partly purified pyrophosphatase from three-day-old cotton seedlings grown under laboratory conditions were studied.

Epicoccum Nigrum as biocontrol agent of Pythium damping-off and root-rot of cotton seedlings

Efficacy of Epicoccum nigrum and its exudate was tested in control the pre- and post-emergence damping-off and root-rot of Egyptian cotton (cv. Giza 83) in vitro and in vivo. Different isolates of Epicoccum nigrum reduced the radial growth of both Pythium debaryanum and P. ultimum significantly, by production considerable inhibition zones. In liquid cultures E. nigrum exudate showed a high fungicidal effect resulting in a significant reduction of the mycelial dry weight of the two investigated Pythium spp. Also E. nigrum exudate inhibited cellulase and pectinase activity by P. debaryanum and P. ultimum. Soaking of cotton seeds in E. nigrum exudate for different intervals resulted in significant reduction of root-rot severity of seedlings as well as the contamination of seeds and seedlings by fungi during and after germination. These treatments also stimulated germination of cotton seeds and enhanced the seedlings vigour significantly. In pot experiments, the use of E. nigrum as a soil mixture or seed dressing significantly alleviated the hazard effect of P. debaryanum. Pythium ultimum seemed to be weak or non pathogen to the used cotton cultivar (Giza 83). Application of E. nigrum or its exudate not only involved in protection of cotton seedlings against Pythium damping-off and root-rot but also enhanced their vigour and growth characteristics. The main conclusion of this study is that E. nigrum could be used successfully as environmentally safe and economic biological control agent to protect cotton (cv. Giza 83) from damping-off and root-rot diseases caused by P. debaryanum.

Proteinase of germinated cotton seeds

A scheme has been developed to isolate and purify proteinase D from 3-day germinated cotton seeds. The physicochemical properties and substrate specificity were studied. It is found that cysteinic proteinase D cleaves auxiliary proteins to low-molecular-weight peptides and free amino acids.

Effects of Light, Different Growth Media, Temperature and Salt Concentrations on Germination of Cotton Seeds (Gossypium hirsutum L. cv. Nazilli 87)

AbstractLaboratory experiments were conducted to study the effects of light, different growth media, temperature, and salt concentrations on the germination ratio, mean germination period, and the beginning of germination of cotton seeds, Gossypium hirsutum L., cv. Nazilli 87. All factors considerably affected the germination rate of cotton seeds, ranging from 47% at darkness to 96% at 16 h of artificial light. The mean germination period varied from 5.6 days at 15°C and 1.3 days at 30°C under illumination and lasted longer at dark. The germination ratio was 94 % without additional salt and decreased from 63 % at salt concentration of 175 mM NaCl 1−1 to only 8.7 % at 300 mM 1−1. The mean germination period ranged from 5.28 days to 13.50 days at salt concentrations of 0–300 mM NaCl l−1, respectively.

Phospholipids of germinating seeds of a cotton plant of the tashkent-1 variety

Phosphatidylinositol with a nontraditional position distribution of the fatty acids has been detected in germinating cotton seeds.

Modification of the reserve proteins during the germination of cotton seeds

The hydrolysis of the 11S globulin begins in the early stages of the germination of cotton seeds and is complete during the first 4–5 days. During the first 3 days, only limited hydrolysis of the reserve protein takes place, and only on the 4th day does it undergo far-reaching hydrolysis, after which the protein cannot be detected either by immunochemical methods or by electrophoresis and analytical ultracentrifugation.

Ethanolic Fermentation in Hypoxic Cotton Seed

Cotton (Gossypium hirsutum L.) roots die within a few hours in the total absence of O2, but can continue growing for several hours at a reduced rate very low at O2 concentrations, even &lt;10 mmol O2 mol−1. The physiology of this adaptive response has not been well characterized. The objective of this study was to determine if ethanolic fermentation occurs in cotton seeds under hypoxic conditions that inhibit but do not prevent radicle growth. Germinating seeds, after 23 h imbibition at 32 °C, were incubated for ≤4.5 h at 28 °C in sealed flasks. Hypoxic conditions (6‐9 mmol O2 mol−1) were imposed by gassing flasks with either N2 or CO2. Fermentation was measured as the production of ethanol and acetaldehyde, which were quantified by gas‐liquid chromatography. Both ethanol and acetaldehyde were readily produced during hypoxia at an average rate of 439 and 9.69 nmol h−1 seed−1, respectively, at 28 °C. Acetaldehyde‐and ethanol‐forming capacity increased substantially during the first 16 h following onset of imbibition. Seeds imbibed under hypoxia for only 3 h produced little ethanol or acetaldehyde. Small amounts of acetaldehyde and ethanol were produced by hydrated seeds imbibed in air. Ethanol produced during fermentation was rapidly assimilated if O2 stress was relieved. During a 2‐h hypoxic stress that promoted fermentation, radicle growth was halted, but resumed at a reduced rate. Inhibition was short‐lived and radicle growth recovered fully in air. Results indicate that ethanolic fermentation is a major metabolic response to hypoxia in germinating cotton seeds.

Cottonseed Malate Synthase

The activity of malate synthase (MS) (EC 4.1.3.2) appears and increases during cotton (Gossypium hirsutum L.) seed maturation, persists through desiccation and imbibition, then increases again following germination. The research reported herein is a comparative study of the synthesis and acquisition of MS into glyoxysomes as they occur in maturing and germinated seeds. Rate-zonal centrifugation of cotyledon extracts revealed that the 5 Svedberg unit (S) cytosolic form of MS was the only form present at 42 days postanthesis (DPA) when activity was first detectable. At later stages (48 DPA, 0 day, 26 hours, and 48 hours), both the 5S and glyoxysomal 20S forms were present, with the 20S form becoming much more prevalent. Western blot analyses revealed that no other form(s) of MS were present in the phosphate-buffered gradients, and that 5S and 20S forms had the same subunit molecular weight in maturing and germinated seeds. Comparisons of radiospecific activity of MS immunoprecipitates following in vivo labeling with [(35)S]methionine for varying time intervals provided strong evidence for a 5S-precursor to 20S-product relationship during both seed maturation and seedling growth. Comparisons of MS labeled in vivo and in vitro in wheat germ and rabbit reticulocyte lysates programmed with poly(A)(+)RNA (from maturing and germinated seeds) revealed no detectable differences in subunit molecular weights. These results reinforced our other data indicating that MS was synthesized in the cytosol and acquired by glyoxysomes in both maturing and germinated cotton seeds without involvement of an intervening aggregate pool in the endoplasmic reticulum, or via processing of a cleavable precursor molecule. MS was translated from poly(A)(+)RNA extracted from 28 DPA cotton seeds. This was nearly 2 weeks before MS activity or protein was detected in vivo. This finding invites further study on the regulation of RNA transcripts during maturation.

Heterogeneity of Catalase in Maturing and Germinated Cotton Seeds

To investigate possible charge and size heterogeneity of catalase (EC 1.11.1.6) in cotton (Gossypium hirsutum L. cv Deltapine 62), extracts of cotyledons from different developmental ages were subjected to nondenaturing polyacrylamide gel electrophoresis and isoelectric focusing. Special precautions (e.g. fresh homogenates, reducing media) were necessary to prevent artefacts due to enzyme modification during extraction and storage. When the gels were stained for enzyme activity, two distinct electrophoretic forms of catalase were resolved in extracts of maturing and mature cotton seeds. In germinated seeds, three additional cathodic forms were detected revealing a total of five electrophoretic variants. In green cotyledons, the two anodic forms characteristic of ungerminated seeds were less active; whereas, the most cathodic form was predominant. All forms of catalase were found in isolated glyoxysomes. Corresponding electrophoretic patterns were found on Western blots probed with anticatalase serum; no immunoreactive, catalytically inactive forms were detected. Western blots of sodium dodecyl sulfate-polyacrylamide gels revealed only one immunoreactive (55 kilodaltons) polypeptide in cotton extracts of all developmental ages. Results from isoelectric focusing and Ferguson plots indicate that the electrophoretic variants of catalase are charge isomers with a molecular weight of approximately 230,000.

Rapid disappearance of cyclopropenoid fatty acids (CPFA) during germination of cottonseed

Rapid disappearance of cyclopropenoid fatty acids (CPFA) during germination of cottonseed

Relationship Between Weathering Deterioration and Germination, Respiratory Metabolism, and Mineral Leaching from Cottonseeds1

Germination of cottonseeds (Gossypiura hirsutum L.) is reduced by preharvest exposure to,weather, particularly if conditions are warm and humid. To identify some of the germination processes affected by weathering deterioration, seedlots of six cultivars were harvested before and after a period of field exposure and comparative germination studies were conducted. Seedling field emergence was reduced by 11 to 33% due to weathering. During imbibition, weathered seeds of sensitive cultivars released more K+, Mn2+, Mg2+, and Ca2+, but less Na+ into the steep solution than did their unweathered counterparts. Leaching of individual minerals was a better indicator of seed quality than was the total release of electrolytes; release of K+ Ca2+ than was significantly correlated with measurementosf seed quality. Respiratory O2 uptake was reduced in deteriorated seeds, with elevated estimates of the RQ after 7.5 h of imbibition. Aeration with 100% O2 increased O2 uptake and reduced the RQ, indicating that O2 diffusion may have limited respiration during early germination. Weathering deterioration of membranes was confirmed by electron microscopy of cotyledonary lipid and protein bodies. Thesed ata indicate that the loss of membrane functional integrity is a major factor responsible for the reduction of germination potential by weathered seeds, and that the release of K+ and Ca2+ into steep water during imbibition may be a good indicator of cottonseed planting quality.

Fungicide and Temperature Affect Leachate‐Predicted Germination of Cotton1

AbstractThe ASA‐610 Automatic Seed Analyzer is used to predict the germination of acid delinted cotton (Gossypium hirsutum L.) seeds, reportedly in 24 h as compared to 7 days by standard methods. The prediction is based on the electrical conductivity of seed leachate, with higher leachate resulting in higher conductivity values and indicating lower germination potential. Because cotton planting seeds usually are treated with fungicides and instruments such as the ASA‐610 may be used to assess planting seed quality without using controlled environmental chambers, this research was initiated. We studied the effects of fungicide treatments and temperature during soaking on ASA‐610‐predicted germination of cotton seeds. Correlations among ASA‐610‐predicted germination and standard (30°C) and cool (18°C) germination tests were determined. Fungicide effects were evaluated by use of aliquots from a single seed lot of ‘Stoneville 213’ treated with 17 different fungicides and/or formulations plus an untreated control and a nine‐entry fungicide test, again applied to aliquots of a single seed lot of Stoneville 213. Samples from 17 commercial planting seed lots were used to study the effects of soaking temperatures and to investigate the correlation between the ASA‐610‐predicted germination and standard germination at 30°C. Of 25 fungicide treatments studied, 20 did not significantly affect ASA‐610‐predicted germination when seeds were soaked for 19 h and partitioned at 55μA/seed. Soaking cotton seeds for 19 h at 18°C resulted in Significantly higher ASA‐610‐predicted germination than soaking at 24 or 30°C. Correlation analysis indicated that the ASA‐610 will not predict accurately the germination of acid‐delinted, commercial planting seeds as defined by standard germination procedures.