Cotton Shoot Research Articles

The basis for the safening of clomazone by phorate insecticide in cotton and inhibitors of cytochrome P450s

Clomazone may be safely used in cotton to manage weeds when applied following treatments of the organophosphate insecticides phorate or disulfoton. The loss of chlorophyll and carotenoids with 6 days of 100 nM clomazone treatment of cotton seedlings was partially prevented with phorate in hydroponic solution in a rate-dependent manner. In a study to examine the timing of safening from a one-day clomazone (100 nM) treatment, maximum safening was achieved when phorate (50 μM) was applied the same day as clomazone. Phorate decreased metabolism of 14C-clomazone to polar metabolites in excised cotton shoots and shoots of intact cotton plants. Microsomal studies of corn shoots showed an NADPH-dependent/cytochrome P450 reaction was inhibited by phorate. Additional studies with corn microsomes, corn seedlings and cotton seedlings supported the basis of clomazone safening is the inhibition of toxic clomazone metabolism by P450 inhibitors.

Effect of insecticides on clomazone absorption, translocation, and metabolism in cotton

Abstract Disulfoton and phorate applied in the seed furrow greatly reduce clomazone phytotoxicity to cotton in the field, whereas aldicarb does not. An experiment was conducted to determine the effect of aldicarb, disulfoton, and phorate on 14C-clomazone absorption, translocation, and metabolism by cotton grown in a sandy loam soil. Clomazone at 0.87 μg g−1 of soil alone or in combination with aldicarb at 0.6 μg g−1 of soil reduced cotton root and shoot growth 26 to 33%. Root and shoot growth were not reduced by clomazone plus disulfoton or phorate at 0.6 μg g−1 of soil. Protection of cotton against injury by clomazone was not explained by reduced absorption or translocation of clomazone or a metabolite to the shoot. Clomazone metabolism was reduced by disulfoton and phorate, thus indicating a clomazone metabolite may be more toxic to cotton. Nomenclature: Aldicarb; clomazone; disulfoton; phorate; cotton, Gossypium hirsutum L. ‘McNair 235’.

Cotton growth and boron distribution in the plant as affected by a temporary deficiency of boron

The knowledge of nutrient mobility is an important tool to define the best fertilizer management and diagnosis techniques. Patterns of boron (B) mobility in plants have been reviewed, but there is very little information on B distribution and mobility in cotton. An experiment was conducted to study plant growth and B distribution in cotton when the nutrient was applied in the nutrient solution or to the leaves, and when a temporary deficiency was imposed. Cotton (Gossypium hirsutum, Latifolia, cv. IAC 22) was grown in nutrient solutions where B was omitted or not for 15 days. Boron was applied to young or mature cotton leaves in some of the minus B treatments. Root growth decreased when the plants were transferred to B solutions, but there was a full recovery when B was replaced in the nutrient medium. Boron deficiency, even when temporary, reduced cotton shoot dry matter yields, plant height and flower and fruit set, and these could not be prevented by foliar application of B. Because of decreased dry matter production, leaves of deficient cotton plants actually showed higher B concentrations than non deficient leaves. This would be misleading when a mature leaf is sampled for diagnosis. If there is any B mobility in cotton phloem, it is very low.

Sample size influences estimation of cotton dry matter, nitrogen accumulation, and lint yield1

Accurate estimates of cotton (Gossypium hirsutum) dry matter accumulation and nitrogen content are important for both production and environmental reasons. One of the important factors in estimate accuracy is sample size. The objective of this investigation was to determine the cotton sample size necessary for acceptable estimates of cotton dry matter, lint yield, and shoot N per 100 kg of lint ratio (NLR) values. Three cotton cultivars (DeltaPine 90, DeltaPine 5415, and Stoneville 474) were planted on 13 May 1997 in an Eunola loamy sand (fine‐loamy, siliceous, thermic Aquic Hapludult) in 9.3‐m2 subplots of a split‐split plot design. Split plots were four sampling dates. Split‐split plots were four sampling techniques [a) four randomly selected plants (4RP), b) 0.3 meter of row (0.3‐m), c) one meter of row (1‐m), and d) two meters of row (2‐m)]. Each entire subplot was harvested on each sampling date after sampling by the four techniques. Shoot dry matter for the whole plot was 7.2 Mg ha‐1, and lint yield was 1.46 Mg ha‐1. Cotton shoot dry matter and NLRs were significantly overestimated by both the 4RP and 0.3‐m techniques, but not by the 1‐ and 2‐m techniques. The NLRs of cultivar subplots varied with cultivar from 9.1 to 11.4. The earliest maturing cultivar, DeltaPine 90, had the lowest NLR and the latest maturing cultivar, Stoneville 474, had the highest NLR. Accurate estimates of cotton dry matter accumulation and N content will likely require 1‐m samples, and 2‐m samples should further improve precision. The NLRs were similar to data (NLR <15) that suggest 1.6 Mg ha‐1 (3‐bale/acre) cotton lint yields can be achieved with less than 250 kg ha‐1 of shoot‐accumulated N.

Improvements in shoot apex regeneration of two fiber crops: cotton and kenaf

Cotton (Gossypium hirsutum L.) and kenaf ( Hibiscus cannabinus L.) belong to the Malvaceae family, and both are used as sources of fibers. Shoot apices from vigorous seedlings aseptically germinated from 3 different cultivars of both cotton and kenaf were used in this study. The cotton and kenaf shoot apex size was between 2–3 mm containing the meristem, unexpanded leaves, and a small portion of the cotyledon. Shoot apices were placed on 18 different media comparing full and 1/2 strength Murashige and Skoog (1962) plus vitamins, and combinations of 0, 0.1, and 1 mg l-1 of naphthaleneacetic acid and 6-benzyladenine (BA). The shoot apices of both crops developed successfully without intervening callus formation, and no significant differences among cultivars were found. An average of 58% of the cotton shoot apices initiated shoot and rooted in full strength Murashige and Skoog (1962) plus vitamins in 6 weeks. For kenaf, an average of 92% of shoot apices initiated shoot and rooted in full strength Murashige and Skoog plus vitamins and 0.1 mg l-1 BA in 3 weeks. All regenerated plants of both crops were phenotypically normal and set seeds.

In vitro shoot-tip grafting improves recovery of cotton plants from culture

A rapid in vitro shoot-tip grafting (STG) technique was adapted to increase recovery of intact cotton plants from shoots developed in culture. Induction of root organogenesis in cotton shoots is genotype dependent and unreliable. The resulting loss of regeneration potential due to failure to form roots can vary from 30 to 80% according to genotype and represents a significant bottleneck in the overall recovery of plants from culture. If the non-rooting shoots are transgenic, the loss in regenerated plant material can be substantial. In vitro grafting of cotton shoots to seedling rootstock proved to be a simple and reliable method allowing 90–100% recovery of non-rooting shoots from culture. Success of any given graft was directly related to scion size (0.8–1.0 cm) and age (14–35 days) of the seedling rootstock. The method appeared to be genotype independent, and varietal differences between rootstock and scion did not effect the rate of plant recovery from culture.

Adaptation of Cotton Shoot Apex Culture to Agrobacterium-Mediated Transformation

A protocol is presented for rapid genotype-independent transformation and regeneration of cotton (Gossypium spp.) from shoots isolated from germinating seedlings. Isolated shoots are inoculated with a super-virulent strain of Agrobacterium tumefaciens, subjected to a mild antibiotic selection, and directly regenerated as shoots in vitro. Shoots do not dedifferentiate and mutation rates are low. Rooted shoots can be obtained within 6–10 weeks of isolation and inoculation depending on the cotton cultivar.

Nitrogen accumulation and partitioning in shoots of cotton plants infested with two-spotted spider mites

In cotton (Gossypium hirsutum L.), leaves are the main site of nitrogen reduction and constitute a large reservoir of organic nitrogen. Foliar herbivores, therefore, are likely to have detrimental effects on the nitrogen economy of the plant. A field experiment was conducted to investigate the effects of two-spotted spider mites (Tetranychus urticae Koch) on the accumulation and partitioning of nitrogen in cotton shoots. Control plants and plants infested with mites 3 times in the growing season were compared. Once established, mite colonies grew exponentially. After peaking at 35–64 mites/leaf, mite numbers declined sharply. Mites markedly affected both shoot nitrogen accumulation and partitioning. The amount of nitrogen in shoots of mite-infested plants peaked earlier than in controls, and reached maximum values that were 50–69% of the controls. Early infestation (at the onset of reproductive growth) had a greater effect than infestations initiated during active reproductive growth. The concentration of nitrogen in leaves declined faster in mite-infested plants than in controls, mostly due to accelerated leaf senescence. This rapid decline in leaf nitrogen concentration could be one of the factors involved in the collapse of mite colonies in heavily infested plants. Nitrogen concentration of stems and reproductive organs was generally greater in mite-infested plants than in controls. Allometric analysis showed that this was related to both the small size of mite-infested plants, and true increases in nitrogen content probably associated with translocation from senescing leaves.

Cotton root and shoot responses to subsurface drip irrigation and partial wetting of the upper soil profile

Cotton root and shoot responses to subsurface drip irrigation and partial wetting of the upper soil profile

Cotton (Gossypium hirsutum) Response to Imazaquin and Imazethapyr Soil Residues

The effects of imazaquin and imazethapyr on cotton planted the year following application to soybean were studied on one silt loam and two clay soils in Arkansas from 1989 to 1991. Imazaquin was applied to soybean at 0.07 kg ai ha−1PPI and POST, 0.14 kg ha−1PPI, PRE, and POST, and sequentially PPI or PRE followed by POST at 0.14 kg ha−1per application. Imazethapyr was applied at 0.035 kg ha−1PPI and POST, 0.07 kg ha−1PPI, PRE, and POST, and sequentially PPI or PRE followed by POST at 0.07 kg ha−1per application. Soil residues of 0.07 kg ha−1imazaquin and imazethapyr did not injure cotton at any location. Residues of 0.14 kg ha−1imazaquin applied sequentially reduced cotton shoot dry weight for 6 wk after emergence on clay but not on silt loam soil. The PPI followed by POST sequential imazaquin treatment (0.28 kg ha−1total imazaquin) delayed initiation of fruiting and reduced yield and lint quality.

Isolation from cotton shoots of an auxin-binding protein regulating the synthesis of RNA

With the aid of a complex method of purification, including affinity chromatography and HPLC, from a fraction of the water-soluble protons of cotton seeds we have isolated a protein which binds the labeled auxin [3HJIAA with high affinity (Kd = 6 nM) and in the presence of IAA stimulates the synthesis of RNAin vitro in a preparation of cottonplant chromatin. In PAAG electrophoresis with sodium dodecyl sulfate, this protein gave a single band corresponding to a molecular mass of 43 kDa. It is assumed that this protein is a receptor for the auxin phytohormone that is responsible for regulating gene activity.

Insecticides Do Not Affect Cotton (Gossypium hirsutum) Response to Imazaquin and Imazethapyr

Field and greenhouse experiments evaluated interactions of soil-applied insecticides and imazaquin and imazethapyr on growth and development of cotton. Imazaquin and imazethapyr were applied PPI at 0 to 6 and 0 to 16 g ae ha−1, respectively, in the greenhouse (plus a no-insecticide control), and 0 to 72 g ha−1in the field in combination with aldicarb, disulfoton, and phorate (without a no-insecticide control) applied in the seed furrow. Cotton shoot fresh weight in the greenhouse experiment decreased linearly as herbicide rates increased. Greater reductions in shoot fresh weight were noted with imazaquin than with imazethapyr. Compared with no insecticide, the methylcarbamate insecticide aldicarb and the organophosphate insecticides disulfoton and phorate did not affect cotton response to either herbicide. In the field, cotton injury increased while stand, yield, and maturity decreased as herbicide rates increased. Delayed maturity was due to a lower percentage of bolls produced on sympodia from main stem nodes four to nine. Imazaquin caused greater injury, greater reductions in stand, greater delays in maturity, and lower yields than did imazethapyr. Earlier maturity was noted with aldicarb-treated cotton. Compared with aldicarb, disulfoton and phorate did not alter cotton response to imazaquin or imazethapyr.

Nitrate Reductase Activity and Nitrate Concentration in Cotton Plant Leaf Blades and Petioles

AbstractGreenhouse studies were conducted to determine the potential of nitrate reductase activity (NRA) as an indicator of the change of N concentration of cotton (Gossypium hirsutum L.) shoots. The results showed that cotton petiole in vivo NRA was not significantly different from NRA in leaf blades during vegetative growth. Nitrate reductase activity (in vivo) in cotton petioles was significantly higher than in leaf blades during reproductive growth. When plants were in the three‐mature‐leaf stage, petiole NRA contributed 16% of total cotton shoot NRA. The petiole biomass was 14% of total shoot fresh weight and 8% of total shoot dry weight. Petiole NRA of plants in the vegetative growth stage increased from 39 to 68 pmol NO−2 g1− FW (fresh weight) s−1 when supplemented with nitrate‐N. These results indicate that cotton petiole NRA is significant and its assay has potential for incorporation into monitoring systems that determine the change of N concentration in cotton shoots.

Indole-Acetic Acid and the Ethylene Precursor, Acc, in the Cotton Fleahopper (Hemiptera: Miridae) and Their Role in Cotton Square Abscission

Indole-acetic acid (IAA) was present in laboratory-reared nymphal and adult cotton fleahoppers, Pseudatomoscelis seriatus (Reuter). The ethylene precursor, 1-aminocyclopropane-1-carboxylic acid (ACC), occurred in nymphal and adult cotton fleahoppers reared in the laboratory and in nymphs collected from the host plants croton, Croton capitatus Michaux; horsemint, Monarda punctata L.; and cutleaf evening primrose, Oenothera laciniata Hill. Cotton fleahopper eggs did not contain ACC. IAA and ACC, when injected into cotton shoot tips at concentrations occurring in cotton fleahoppers, induced ethylene production to levels higher than in controls but lower than in terminals infested with cotton fleahoppers. Thus the IAA and ACC in cotton fleahoppers may contribute partially to the mechanism by which cotton fleahoppers promote ethylene-mediated abscission of cotton flower buds.

Opines stimulate induction of the vir genes of the Agrobacterium tumefaciens Ti plasmid

Upon incubation of Agrobacterium tumefaciens A348 with acetosyringone, the vir genes encoded by the Ti (tumor-inducing) plasmid are induced. The addition of certain opines, including octopine, nopaline, leucinopine, and succinamopine, enhanced this induction 2- to 10-fold. The compounds mannopine, acetopine, arginine, pyruvate, and leucine did not stimulate the induction of the vir genes to such an extent. The enhancement of vir gene induction by opines depended on acetosyringone and the genes virA and virG. Opines stimulated the activity of the vir genes, the double-stranded cleavage of the T (transferred)-DNA at the border repeat sequences, and the production of T-strands by the bacterium. The transformation efficiency of cotton shoot tips was markedly increased by the addition of acetosyringone and nopaline at the time of infection.

Stimulation of Ethylene Production in Cotton by Salivary Enzymes of the Cotton Fleahopper (Heteroptera: Miridae)

Centrifuged and filter-sterilized salivary homogenates of male and female cotton fleahoppers (CFH), Pseudatomoscelis seriatus (Reuter), were found to contain a polygalacturonase (pectinase), an enzyme capable of breaking down pectic materials in the middle lamella of plants. Salivary preparations from male CFH had more enzyme activity than homogenates from female salivary glands. Salivary extracts were strong elicitors of stress ethylene production when injected into excised cotton shoot tips. Excised cotton buds injected with male salivary preparations produced ethylene at higher rates than those buds injected with female preparations. Enzyme activity and ethylene-inducing capacity of these salivary homogenates were destroyed by boiling and reduced by long-term storage. Ethylene production by cotton buds also was induced by solutions of commercial pectic enzymes.

Cotton Fleahopper and Associated Microorganisms as Components in the Production of Stress Ethylene by Cotton

Excised cotton terminal buds incubated with adults or nymphs of the cotton fleahopper (CFH), Pseudatomoscelis seriatus (Reuter), produced ethylene at theoretical abscission-inducing rates by 24 h after introduction of the insect. Inoculation of cotton shoot tips with three microorganisms commonly associated with CFH and cotton in all cases promoted ethylene production to theoretical abscission-inducing rates by 24 h after inoculation. CFH alone or injection of microorganisms consistently caused cotton shoot tips to darken and become soft. These changes paralleled the rise in ethylene production and did not occur in control shoot tips. Of the three microorganisms, Xanthomonas campestris pv malvacearum (Smith) Dye (XCM) produced little ethylene when grown in culture, while the two fungi, Penicillium purpurogenum Stoll and P. glabrum (Wehmer) Westling, produced higher levels. The parallel between plant response to CFH, XCM, and CFH + XCM suggests a similar mechanism of ethylene induction by these two stress agents. Since a portion of the CFH were devoid of microorganisms, yet their impact on ethylene production by cotton tissue was uniform, we propose that the primary mechanism of ethylene induction involves the insect's salivary fluids which contain cell wall hydrolyzing enzymes.

Polysaccharides in the culture medium of cotton cells cultured in vitro

Glucose-containing polysaccharides have been isolated from the culture medium of cotton ( Gossypium hirsutum L.) ovules and compared to polysaccharides secreted into the culture medium from cells derived from cotton shoot tip meristem tissue. In both systems fucogalactoxyloglucans and Aspinall type II arabino-galactans similar to those already known in other dicotyledons were found.

Absorption, Translocation, and Metabolism of Fluridone in Selected Crop Species

The uptake, translocation, and metabolism of the herbicide fluridone 1-methyl-3-phenyl-5-[3-(trifluoromethyl)phenyl]-4(1H)-pyridinone was studied in cotton (Gossypium hirsutum L. ‘Stoneville 213’) (fluridone tolerant) and corn (Zea mays L. ‘Migro 5040’), soybean [Glycine max (L.) Merr. ‘Calland’], and rice (Oryza sativa L. ‘Nato’) (fluridone susceptible). Uptake studies with 14C fluridone demonstrated that all species absorbed radioactivity with rice having the highest concentration. Equivalent concentrations of radioactivity were observed in corn, cotton, and soybean. Absorbed fluridone was retained primarily in the roots and the basal region of the stem of cotton, while in the herbicide susceptible species fluridone was readily translocated into the shoots. No appreciable metabolism of fluridone was observed in the roots or shoots of cotton and soybean. Tolerance of cotton to fluridone was primarily attributed to the limited translocation of the compound.

Comparative uptake and metabolism of methazole in prickly sida and cotton

The comparative uptake and metabolism of 14C-labeled 2-(3,4-dichlorophenyl)-4-methyl-1,2,4-oxadiazolidine-3,5-dione (methazole), a herbicide, in prickly sida ( Sida spinosa L.) and cotton ( Gossypium hirsutum L.) were investigated as physiological bases for herbicidal selectivity, using thin layer chromatography, autoradiography, and liquid scintillation counting. Prickly sida and cotton readily absorbed and translocated 14C from nutrient solution containing [ 14C]methazole. Only acropetal translocation of 14C was observed. Methazole was rapidly metabolized to 1-(3,4-dichlorophenyl)-3-methylurea (DCPMU) and other metabolites by both species. Although metabolism appeared to be qualitatively the same, quantitative differences between species were evident. Methazole was converted to DCPMU (also phytotoxic) more readily by prickly sida than cotton; however, DCPMU was more readily detoxified to 1-(3,4-dichlorophenyl) urea (DCPU) by cotton than prickly sida. More 14C per unit weight was present in the prickly sida shoots than in cotton shoots. Also, a larger portion of the methanol-extractable 14C was herbicidal in the shoots of prickly sida than of cotton. Thus, the differential tolerances of prickly sida and cotton to methazole may be explained, in part, by differential uptake and metabolism of methazole and DCPMU.