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Ascorbate oxidase (AO) plays important roles in plant growth and development. Previously, we reported a cotton AO gene that acts as a positive factor in cell growth. Investigations on Gossypium hirsutum AO ( GhAO ) family genes and their multiple functions are limited. The present study identified eight GhAO family genes and performed bioinformatic analyses. Expression analyses of the tissue specificity and developmental feature of GhAO s displayed their diverse expression patterns. Interestingly, GhAO1A demonstrated the most rapid significant increase in expression after 1 h of light recovery from the dark. Additionally, the transgenic ao1-1 / GhAO1A Arabidopsis lines overexpressing GhAO1A in the Arabidopsis ao1-1 late-flowering mutant displayed a recovery to the normal phenotype of wild-type plants. Moreover, compared to the ao1-1 mutant, the ao1-1 / GhAO1A transgenic Arabidopsis presented delayed leaf senescence that was induced by the dark, indicating increased sensitivity to hydrogen peroxide (H 2 O 2 ) under normal conditions that might be caused by a reduction in ascorbic acid (AsA) and ascorbic acid/dehydroascorbate (AsA/DHA) ratio. The results suggested that GhAOs are functionally diverse in plant development and play a critical role in light responsiveness. Our study serves as a foundation for understanding the AO gene family in cotton and elucidating the regulatory mechanism of GhAO1A in delaying dark-induced leaf senescence.

Different cotton (Gossypium hirsutum L.)-wheat (Triticum aestivum) planting patterns are widely applied in the Yellow River Valley of China, and crop yield mainly depends on light interception. However, little information is available on how cotton canopy light capturing and yield distribution are affected by planting patterns. Hence, field experiments were conducted in 2016 and 2017 to study the response of cotton canopy light interception, square and boll distribution, the leaf area index (LAI) and biomass accumulation to three planting patterns: a cotton monoculture (CM, planted on 15 May) system, a cotton/wheat relay intercropping (CWI, planted on 15 May) system, in which three rows of wheat rows were intercropped with one row of cotton, and a system in which cotton was directly seeded after wheat (CWD, planted on 15 June). The following results were obtained: 1) greater light capture capacity was observed for cotton plants in the CM and CWI compared with the CWD, and the light interception of the CM was 22.4% and 51.4% greater than that of the CWI and CWD, respectively, at 30 days after sowing (DAS) in 2016; 2) more bolls occurred at the first sympodial position (SP) than at other SPs for plants in the CM; 3) based on the LAI and biomass accumulation, the cotton growth rate was the greatest in CWD, followed by CM and CWI; and 4) the CM produced significantly greater yields than did the other two treatments because it yielded more bolls and greater boll weight. Information on the characteristics of cotton growth and development in response to different planting patterns would be helpful for understanding the response of cotton yields to planting patterns and would facilitate the improvement of cotton productivity., Competing Interests: The authors have declared that no competing interests exist.

Chloroplast movement mediated by the plant-specific phototropin blue light photoreceptors is crucial for plants to cope with fluctuating light conditions. While chloroplasts accumulate at weak light-illuminated areas, chloroplast avoidance response mediated primarily by the phototropin2 (phot2) receptor is induced by strong light illumination. Although extensive studies have been performed on phot2-mediated chloroplast avoidance in the model plant Arabidopsis, little is known on the role of the corresponding PHOT2 orthologs in chloroplast movement in cotton. In this study, we found that chloroplast avoidance movement also occurs in the tetraploid G. hirsutum and two diploid species, G. arboreum and G. raimondii, albeit with distinct features. Further bioinformatics and genetic analysis identified the cotton PHOT2 ortholog, GhPHOT2-1, which retained a conserved role in plant chloroplast avoidance movement under strong blue light. Ghphot2-1was localized in the plasma membrane and formed aggregates after high blue light irradiation. Constitutive expression of GhPHOT2-1 restored chloroplast avoidance and accumulation response, as well as phototropism, and leaf flattening characteristics of the Arabidopsis phot2 or phot1 phot2 mutants. On the contrary, silencing of GhPHOT2-1 by virus-induced gene silencing (VIGS) disrupted high blue light-induced chloroplast avoidance movement and caused photo damage in cotton leaves. Taken together, these findings demonstrated that GhPHOT2-1 is a conserved PHOT2 ortholog in regulating chloroplast avoidance and the other aforementioned phot2-mediated responses, implicating its potential role for improving high light tolerance in cotton cultivars., (Copyright © 2018 Elsevier Masson SAS. All rights reserved.)

Genes of the CENTRORADIALIS/TERMINAL FLOWER 1/SELF-PRUNING (CETS) family influence meristem identity by controlling the balance between indeterminate and determinate growth, thereby profoundly impacting plant architecture. Artificial selection during cotton (Gossypium hirsutum) domestication converted photoperiodic trees to the day-neutral shrubs widely cultivated today. To understand the regulation of cotton architecture and exploit these principles to enhance crop productivity, we characterized the CETS gene family from tetraploid cotton. We demonstrate that genes of the TERMINAL FLOWER 1 (TFL1)-like clade show different roles in regulating growth patterns. Cotton has five TFL1-like genes: SELF-PRUNING (GhSP) is a single gene whereas there are two TFL1-like and BROTHER OF FT (BFT)-like genes, and these duplications are specific to the cotton lineage. All genes of the cotton TFL1-like clade delay flowering when ectopically expressed in transgenic Arabidopsis, with the strongest phenotypes failing to produce functional flowers. GhSP, GhTFL1-L2, and GhBFT-L2 rescue the early flowering Attfl1-14 mutant phenotype, and the encoded polypeptides interact with a cotton FD protein. Heterologous promoter::GUS fusions illustrate differences in the regulation of these genes, suggesting that genes of the GhTFL1-like clade may not act redundantly. Characterizations of the GhCETS family provide strategies for nuanced control of plant growth.

Background: We previously reported the development of a set of Gossypium hirsutum-G. australe alien chromosome addition lines. Naturally, however, G. hirsutum-G. australe chromosome exchanges were very limited, impeding the stable transference of useful genes from G. australe (G 2 G 2 genome) into the most cultivated cotton, G. hirsutum (AADD)., Results: In the present report, the pollen from a pentaploid (2n = AADDG 2 ) of G. hirsutum-G. australe was irradiated with seven different doses ranging from 10 to 40 Grays and used to pollinate emasculated flowers of G. hirsutum over three consecutive years. Irradiation greatly increased the genetic recombination rates of the G. hirsutum and G. australe chromosomes and a total of 107 chromosome introgression individuals in 192 GISH-negative (with no GISH signal on chromosome) survived individuals, 11 chromosome translocation individuals (containing 12 chromosome translocation events) and 67 chromosome addition individuals were obtained in 70 GISH-positive (with GISH signal(s) on chromosome(s)) survived individuals, which are invaluable for mining desirable genes from G. australe. Multicolor genomic in situ hybridization results showed that there were three types of translocation, whole arm translocation, large alien segment translocation and small alien segment translocation, and that all translocations occurred between the G 2 -genome and the A-subgenome chromosomes in G. hirsutum. We also found that higher doses induced much higher rates of chromosome variation but also greatly lowered the seed viability and seedling survivability., Conclusions: Irradiation has been successfully employed to induce chromosome introgressions and chromosome translocations and promote chromosome exchanges between cultivated and wild species. In addition, by balancing the rates of chromosome introgression and translocation to those of seed set, seed germination, and seedling rates in the M1 generation, we conclude that the dosage of 20 Grays is the most suitable. The established methodology may guide the utilization of the tertiary gene pool of Gossypium species such as G. australe in cotton breeding in the future.

This study is to test the effects of Bt gene introduction on the foliar water/nitrogen use efficiency in cotton. We measured leaf stomatal conductance, photosynthetic rate, and transpiration rate under light saturation condition at different stages of a conventional cultivar (zhongmian no. 16) and its counterpart Bt cultivar (zhongmian no. 30) that were cultured on three levels of fertilization, based on which leaf instantaneous water use efficiency was derived. Leaf nitrogen concentration was measured to calculate leaf photosynthetic nitrogen use efficiency, and leaf δ(13)C was used to characterize long term water use efficiency. Bt cultivar was found to have lower stomatal conductance, net photosynthetic rates and transpiration rates, but higher instantaneous and long time water use efficiency. In addition, foliar nitrogen concentration was found to be higher but net photosynthetic rate was lower in the mature leaves of Bt cultivar, which led to lower photosynthetic nitrogen use efficiency. This might result from the significant decrease of photosynthetic rate due to the decrease of stomatal conductance. In conclusion, our findings show that the introduction of Bt gene should significantly increase foliar water use efficiency but decrease leaf nitrogen use efficiency in cotton under no selective pressure.

Identifying the characteristics of light interception and utilization is of great significance for improving the potential photosynthetic activity of plants. The present research investigates the differences in absorbing and converting photosynthetically active radiation (PAR) among various cotton cultivars. Field experiments were conducted in 2012, 2013 and 2014 in Anyang, Henan, China. Ten cultivars with different maturity and plant architectures were planted at a density of 60,000 plants ha-1 in randomized blocks, with three replicates. The spatial distribution of light in canopy was measured and quantified with a geo-statistical method, according to which the cumulative amount of intercepted radiation was calculated by Simpson 3/8 rules. Finally, light interception was analyzed in association with the biomass accumulation of different cultivars. The key results were: (1) late-maturing varieties with an incompact plant architecture captured more solar radiation throughout the whole growth period than middle varieties with columnar architecture and even more than early varieties with compact architecture, and they produced more biomass; (2) the highest PAR interception ratio and the maximum biomass accumulation rate occurred during the blossoming and boll-forming stage, when leaf area index (LAI) reached its peak; (3) the distribution within the canopy presented a significant spatial heterogeneity, and at late growing stage, the PAR was mainly intercepted by upper canopies in incompact-type plant communities, but was more homogeneous in columnar-type plants; however, the majority of radiation was transmitted through the canopy in compact-type colonies; (4) there was not a consistent variation relationship between the cumulative intercepted PAR (iPAR) and biomass among these cultivars over the three years of the study. Based on these results, we attempted to clarify the distinction in light spatial distribution within different canopies and the patterns of PAR interception in diverse cotton cultivars with different hereditary characters, thereby providing a significant basis for researchers to select cultivars with appropriate growth period and optimal plant architecture for improvement of light interception and utilization.

Cotton knitted fabrics were manufactured with different yarn types (conventional ring spun yarn and torque-free ring spun yarn) with different fibre types (combed cotton and combed Supima cotton) and yarn fineness (Ne30 and Ne40). These fabrics were then dyed with three types of dye (reactive, direct and sulphur dye) with three dye concentrations (0.1%, 1.0% and 5.0% on-weight of fabric (owf)) in three colours (red, yellow and blue). This study examined the impact of constructional parameters and dyeing on ultraviolet (UV) protection properties of cotton knitted fabric. In-vitro test with spectrophotometer was used for evaluating the UV protection property of dyed cotton knitted fabrics. Among the six parameters investigated, fineness of yarn and dye concentration were the most significant factors affecting UPF while the color effect is the least significant. Experimental results revealed that the UPF value of dyed fabrics made from combed cotton is generally higher than the combed Supima cotton since combed cotton is composed of shorter fibres which facilitate the blocking or absorption of UV radiation. Second, fabrics made with twist yarn (i.e. ring spun yarn) have higher UPF value than the corresponding ESTex one (i.e. torque-free yarn) in general since fabrics made with ring spun yarn tend to shrink during wet processing and so it is more compact. Third, the UPF value of fabrics made with 30Ne yarn was higher than the 40Ne one since it is thicker and has lower fabric porosity. Fourth, fabrics dyed with lower concentration of dye gave the lowest UPF. Fifth, the sulphur dyed samples performed worse than the reactive and direct dyed samples in terms of UV protection property. Sixth, there is no significant difference in UPF for red, yellow and blue coloured fabrics. Seventh, this study also demonstrated that lightness of fabric is negatively related to UV protection property.

Clothing provides intrinsic ultraviolet (UV) protection that can be improved by colouration. However, the daily wearing condition can undermine the UV protection of coloured clothing wherein garments are stretched by body movement and/or wetted by perspiration of wearers. Knitwear is an indispensable clothing in summer, but its UV protection against wearing conditions lacks extensive study especially in a fabric structural approach. This article aimed at narrowing the research gap by focusing on the UV protection against stretch and wetness provided by various knitted fabric constructions incorporating the knit, tuck and miss stitches. The results show that the black knitted fabrics exhibit a significant reduction in the UV protection factor by 53% on average at a 10% stretch level. Knitted fabrics with miss stitches retained good UV protection even when the fabrics were stretched by 20% of its original dimensions., (© The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

Purpose: The purpose of the investigation was to induce somaclonal variations by gamma rays (GR), ethylmethane sulphonate (EMS) and sodium azide (SA) during in vitro organogenesis of cotton., Materials and Methods: The shoot tip explants were irradiated with 5-50 Gray (Gy) GR (Cobalt 60), 0.5-5.0 mM EMS and SA separately, and inoculated on Murashige and Skoog (MS) medium fortified with plant growth regulator (PGR) for organogenesis. The plantlets with well-developed root systems were acclimatized and transferred into the experimental field to screen the somaclonal variations during growth and development., Results: The number of somaclonal variations was observed in growth of irradiated/treated shoot tips, multiplication, plantlet regeneration and growth in vitro and ex vitro. The lower doses/concentrations of mutagenic treatments showed significant enhancement in selected agronomical characters and they showed decreased trends with increasing doses/concentrations of mutagenic agents., Conclusions: The results of the present study revealed the influence of lower doses/concentrations of mutagenic treatments on in vitro and ex vitro growth of cotton plantlets and their significant improvement in agronomical characters which needs further imperative stability analysis. The present observations showed the platform to use lower doses/concentrations of mutagenic agents to induce variability for enhanced agronomical characters, resistant and tolerant cotton varieties.

The partitioning of light is very difficult to assess, especially in discontinuous or irregular canopies. The aim of the present study was to analyze the spatial distribution of photosynthetically active radiation (PAR) in a heterogeneous cotton canopy based on a geo-statistical sampling method. Field experiments were conducted in 2011 and 2012 in Anyang, Henan, China. Field plots were arranged in a randomized block design with the main plot factor representing the plant density. There were 3 replications and 6 densities used in every replicate. The six plant density treatments were 15,000, 33,000, 51,000, 69,000, 87,000 and 105,000 plants ha(-1). The following results were observed: 1) transmission within the canopy decreased with increasing density and significantly decreased from the top to the bottom of the canopy, but the greatest decreases were observed in the middle layers of the canopy on the vertical axis and closing to the rows along the horizontal axis; 2) the transmitted PAR (TPAR) of 6 different cotton populations decreased slowly and then increased slightly as the leaves matured, the TPAR values were approximately 52.6-84.9% (2011) and 42.7-78.8% (2012) during the early cotton developmental stage, and were 33.9-60.0% (2011) and 34.5-61.8% (2012) during the flowering stage; 3) the Leaf area index (LAI) was highly significant exponentially correlated (R(2) = 0.90 in 2011, R(2) = 0.91 in 2012) with the intercepted PAR (IPAR) within the canopy; 4) and a highly significant linear correlation (R(2) = 0.92 in 2011, R(2) = 0.96 in 2012) was observed between the accumulated IPAR and the biomass. Our findings will aid researchers to improve radiation-use efficiency by optimizing the ideotype for cotton canopy architecture based on light spatial distribution characteristics.

Much effort has been expended to improve irrigation efficiency and drought tolerance of agronomic crops; however, a clear understanding of the physiological mechanisms that interact to decrease source strength and drive yield loss has not been attained. To elucidate the underlying mechanisms contributing to inhibition of net carbon assimilation under drought stress, three cultivars of Gossypium hirsutum were grown in the field under contrasting irrigation regimes during the 2012 and 2013 growing season near Camilla, Georgia, USA. Physiological measurements were conducted on three sample dates during each growing season (providing a broad range of plant water status) and included, predawn and midday leaf water potential (ΨPD and ΨMD), gross and net photosynthesis, dark respiration, photorespiration, and chlorophyll a fluorescence. End-of-season lint yield was also determined. ΨPD ranged from -0.31 to -0.95MPa, and ΨMD ranged from -1.02 to -2.67MPa, depending upon irrigation regime and sample date. G. hirsutum responded to water deficit by decreasing stomatal conductance, increasing photorespiration, and increasing the ratio of dark respiration to gross photosynthesis, thereby limiting PN and decreasing lint yield (lint yield declines observed during the 2012 growing season only). Conversely, even extreme water deficit, causing a 54% decline in PN, did not negatively affect actual quantum yield, maximum quantum yield, or photosynthetic electron transport. It is concluded that PN is primarily limited in drought-stressed G. hirsutum by decreased stomatal conductance, along with increases in respiratory and photorespiratory carbon losses, not inhibition or down-regulation of electron transport through photosystem II. It is further concluded that ΨPD is a reliable indicator of drought stress and the need for irrigation in field-grown cotton., (Copyright © 2014 Elsevier GmbH. All rights reserved.)

In this project, we hypothesize that cotton (Gossypium hirsutum) leaf temperature and the responses of leaf photosynthesis to temperature will change as the leaves expand and that differences between young and mature leaves will be associated with the proportion of saturated fatty acids in thylakoid and other membrane lipids. To that end, we studied main stem leaves obtained from plants growing in a temperature controlled greenhouse and at different times in the field season. We found that young leaves (∼5d old) had higher mid day temperatures, lower stomatal conductance and higher thermal optima as measured by ΦPSII temperature curves than did more mature leaves (∼13d old). Young leaves also had significant differences in fatty acid saturation with the warmer, young leaves having a higher proportion of palmitic acid (16:0) and lower linoleic acid (18:3) in total lipid extracts and higher 16:0 and lower palmitoleic acid (16:1) in the chloroplast membrane phosphoglycerides, digalactosyldiacylglycerol (in the greenhouse) and phosphatidylglycerol when compared with cooler, more mature leaves. Later in the growing season, leaf temperature, stomatal conductance and ΦPSII temperature curves for young and more mature leaves were similar and the proportion of 16:0 fatty acids decreased and 16:1 increased in phosphatidylglycerol. We conclude that changes in temperature as cotton leaves expand leads to alterations in the fatty acid composition of thylakoid and other membranes and, consequently, influence photosynthesis/temperature responses., (Copyright © 2013 Elsevier GmbH. All rights reserved.)

Using radioactively labelled amino acids to investigate repair of photoinactivated photosystem II (PS II) gives only a relative rate of repair, while using chlorophyll fluorescence parameters yields a repair rate coefficient for an undefined, variable location within the leaf tissue. Here, we report on a whole-tissue determination of the rate coefficient of photoinactivation k i , and that of repair k r in cotton leaf discs. The method assays functional PS II via a P700 kinetics area associated with PS I, as induced by a single-turnover, saturating flash superimposed on continuous background far-red light. The P700 kinetics area, directly proportional to the oxygen yield per single-turnover, saturating flash, was used to obtain both k i and k r . The value of k i , directly proportional to irradiance, was slightly higher when CO2 diffusion into the abaxial surface (richer in stomata) was blocked by contact with water. The value of k r , sizable in darkness, changed in the light depending on which surface was blocked by contact with water. When the abaxial surface was blocked, k r first peaked at moderate irradiance and then decreased at high irradiance. When the adaxial surface was blocked, k r first increased at low irradiance, then plateaued, before increasing markedly at high irradiance. At the highest irradiance, k r differed by an order of magnitude between the two orientations, attributable to different extents of oxidative stress affecting repair (Nishiyama et al., EMBO J 20: 5587-5594, 2001). The method is a whole-tissue, convenient determination of the rate coefficient of photoinactivation k i and that of repair k r .

The red leaf coloration of Empire Red Leaf Cotton (ERLC) (Gossypium hirsutum L.), resulted from anthocyanin accumulation in light, is a well known dominant agricultural trait. However, the underpin molecular mechanism remains elusive. To explore this, we compared the molecular biological basis of anthocyanin accumulation in both ERLC and the green leaf cotton variety CCRI 24 (Gossypium hirsutum L.). Introduction of R2R3-MYB transcription factor Rosea1, the master regulator anthocyanin biosynthesis in Antirrhinum majus, into CCRI 24 induced anthocyanin accumulation, indicating structural genes for anthocyanin biosynthesis are not defected and the leaf coloration might be caused by variation of regulatory genes expression. Expression analysis found that a transcription factor RLC1 (Red Leaf Cotton 1) which encodes the ortholog of PAP1/Rosea1 was highly expressed in leaves of ERLC but barely expressed in CCRI 24 in light. Ectopic expression of RLC1 from ERLC and CCRI 24 in hairy roots of Antirrhinum majus and CCRI 24 significantly enhanced anthocyanin accumulation. Comparison of RLC1 promoter sequences between ERLC and CCRI 24 revealed two 228-bp tandem repeats presented in ERLC with only one repeat in CCRI 24. Transient assays in cotton leave tissue evidenced that the tandem repeats in ERLC is responsible for light-induced RLC1 expression and therefore anthocyanin accumulation. Taken together, our results in this article strongly support an important step toward understanding the role of R2R3-MYB transcription factors in the regulatory menchanisms of anthocyanin accumulation in red leaf cotton under light.

Nutrients such as phosphorus may exert a major control over plant response to rising atmospheric carbon dioxide concentration (CO2), which is projected to double by the end of the 21st century. Elevated CO2 may overcome the diffusional limitations to photosynthesis posed by stomata and mesophyll and alter the photo-biochemical limitations resulting from phosphorus deficiency. To evaluate these ideas, cotton (Gossypium hirsutum) was grown in controlled environment growth chambers with three levels of phosphate (Pi) supply (0.2, 0.05 and 0.01mM) and two levels of CO2 concentration (ambient 400 and elevated 800μmolmol(-1)) under optimum temperature and irrigation. Phosphate deficiency drastically inhibited photosynthetic characteristics and decreased cotton growth for both CO2 treatments. Under Pi stress, an apparent limitation to the photosynthetic potential was evident by CO2 diffusion through stomata and mesophyll, impairment of photosystem functioning and inhibition of biochemical process including the carboxylation efficiency of ribulose-1,5-bisphosphate carboxylase/oxyganase and the rate of ribulose-1,5-bisphosphate regeneration. The diffusional limitation posed by mesophyll was up to 58% greater than the limitation due to stomatal conductance (gs) under Pi stress. As expected, elevated CO2 reduced these diffusional limitations to photosynthesis across Pi levels; however, it failed to reduce the photo-biochemical limitations to photosynthesis in phosphorus deficient plants. Acclimation/down regulation of photosynthetic capacity was evident under elevated CO2 across Pi treatments. Despite a decrease in phosphorus, nitrogen and chlorophyll concentrations in leaf tissue and reduced stomatal conductance at elevated CO2, the rate of photosynthesis per unit leaf area when measured at the growth CO2 concentration tended to be higher for all except the lowest Pi treatment. Nevertheless, plant biomass increased at elevated CO2 across Pi nutrition with taller plants, increased leaf number and larger leaf area., (Copyright © 2013 Elsevier GmbH. All rights reserved.)

Two different pre-sowing techniques have been investigated for their influence in an important industrial plant, namely cotton. Priming methods are very useful for agricultural practices because they improve crop seedling establishment, especially when environmental conditions are not optimum. Pulsed electromagnetic fields have been found to promote germination and improve early growth characteristics of cotton seedlings. Such priming techniques are especially valuable in organic cultivation, where chemical compounds are prohibited. PEG treatment showed an enhancement in some measurements, however in some cases the results were not statistically different compared to control plants. In addition, PEG treatment is a sophisticated method that is far from agricultural practices and farmers. In this research, two different ages of seeds were used (1- and 2-year-old) in order to investigate the promotory effects of priming techniques. Magnetic field treatment of 15 min was found to stimulate germination percentage and to promote seeds, resulting in 85% higher values than control seeds under real field conditions. Furthermore, seeds that were treated with magnetic field performed better in terms of early-stage measurements and root characteristics.

Taking the super-high yielding cotton fields (lint yield > or = 4000 kg x hm(-2)) in Xinjiang as the objects, this paper studied the canopy light distribution, photosynthetic rate, and dry matter accumulation at different growth stages, as well as the relationships between the characteristics of canopy light environment and the photosynthetic production. From full flowering stage to late full bolling stage, the light absorption proportion in the upper, middle and lower canopy layers in the super-high yielding cotton fields was 2:2:1, and the canopy transmission coefficients for radiation penetration and diffuse penetration were 0.20-0.55 and 0.22-0.56, respectively, being at reasonable level. The leaves in the middle and lower canopy layers could well accept light, and the leaf photosynthetic rate had little difference among different canopy layers. Compared with high yielding (3500 kg x hm(-2)) and generally high yielding (3000 kg x hm(-2)) cotton fields, super-high yielding cotton field had higher leaf area index and the highest canopy photosynthesis rate at early full boiling stage, and slowly decreased leaf area index, higher canopy photosynthesis rate, increased contribution of non-foliar organs to photosynthetic production, and larger dry matter accumulation from early boll-opening stage to full boll-opening stage. In cotton cultivation, to adjust the canopy structure for the equidistribution of light and canopy photosynthesis capacity in vertical direction could be the important strategy for the efficient utilization of absorbed light energy and the realization of super-high yielding.

Phospholipase Dalpha (PLDalpha) was isolated from cultivated cotton (Gossypium hirsutum) and characterized. Two PLDalpha genes were identified in the allotetraploid genome of G. hirsutum, derived from its diploid progenitors, G. raimondii and G. arboreum. The genes contained three exons and two introns. The translated products shared a 98.6% homology and were designated as GrPLDalpha and GaPLDalpha. Their ORFs encoded a polypeptide of 807 amino acids with a predicted molecular mass of 91.6 kDa sharing an 81-82% homology with PLDalpha1 and PLDalpha2 from A. thaliana. A possible alternative splicing event was detected at the 5' untranslated region which, however, did not result in alternative ORFs. Cold stress (10 degrees C or less) resulted in gene induction which was suppressed below control levels (25 degrees C or 22 degrees C growth temperature) when plants were acclimated at 17 degrees C before applying the cold treatment. Differences in the expression levels of the isoforms were recorded under cold acclimation, and cold stress temperatures. Expression was light regulated under growth, acclimation, and cold stress temperatures. Characterization of the products of lipid hydrolysis by the endogenous PLDalpha indicated alterations in lipid species and a variation in levels of the signalling molecule phosphatidic acid (PA) following acclimation or cold stress.

Henna is a very popular plant in many countries, including Tunisia. Henna leaves have been used for thousands of years as a medicine, as a cosmetic and also for dyeing textile fabrics. This paper investigates the color modification of cotton, which has been colored by henna, due to gamma-ray irradiation. A cotton fabric tinted by means of a henna solution is irradiated using a (60)Co source at doses ranging from 0 to 25 kGy with a dose rate of 146.53 Gy/min. Decoloration of the henna dye in cotton fabrics was observed by studying variation of the L* and the h degrees as a function of the irradiation dose. This work reveals that cotton colored by henna can be used as a new indicator to differentiate between an unirradiated and irradiated product.

Impacts of salinity become severe when the soil is deficient in oxygen. Oxygation (using aerated water for subsurface drip irrigation of crop) could minimize the impact of salinity on plants under oxygen-limiting soil environments. Pot experiments were conducted to evaluate the effects of oxygation (12% air volume/volume of water) on vegetable soybean (moderately salt tolerant) and cotton (salt tolerant) in a salinized vertisol at 2, 8, 14, 20 dS/m EC(e). In vegetable soybean, oxygation increased above ground biomass yield and water use efficiency (WUE) by 13% and 22%, respectively, compared with the control. Higher yield with oxygation was accompanied by greater plant height and stem diameter and reduced specific leaf area and leaf Na+ and Cl- concentrations. In cotton, oxygation increased lint yield and WUE by 18% and 16%, respectively, compared with the control, and was accompanied by greater canopy light interception, plant height and stem diameter. Oxygation also led to a greater rate of photosynthesis, higher relative water content in the leaf, reduced crop water stress index and lower leaf water potential. It did not, however, affect leaf Na+ or Cl- concentration. Oxygation invariably increased, whereas salinity reduced the K+ : Na+ ratio in the leaves of both species. Oxygation improved yield and WUE performance of salt tolerant and moderately tolerant crops under saline soil environments, and this may have a significant impact for irrigated agriculture where saline soils pose constraints to crop production.

2,7-Dihydroxycadalene and lacinilene C, sesquiterpenoid phytoalexins that accumulate at infection sites during the hypersensitive resistant response of cotton foliage to Xanthomonas campestris pv. malvacearum, have light-dependent toxicity toward host cells, as well as toward the bacterial pathogen. Adaxial epidermal cells surrounding and sometimes covering infection sites turn red. The red cells exhibited 3-4-fold higher absorption at the photoactivating wavelengths of sunlight than nearby colorless epidermal cells. Red epidermal cells protected underlying palisade mesophyll cells from the toxic effects of 2,7-dihydroxycadalene plus sunlight, indicating a role for epidermal pigments in protecting living cells that surround infection sites from toxic effects of the plant's own phytoalexins. A semi-quantitative survey of UV-absorbing substances extracted from epidermal strips from inoculated and mock-inoculated cotyledons indicated that the principal increase in capacity to absorb the photoactivating wavelengths was due to a red anthocyanin and a yellow flavonol, which were identified as cyanidin-3-O-beta-glucoside and quercetin-3-O-beta-glucoside, respectively.

Influence of radiation doses (7Li) on cellular metabolism, specially endogenous hormonal level, was studied in monolayer of cotton fibers. Changes in endogenous phytohormone level were determined with two different fluences of 7Li equivalent to radiation doses of 1 Gy and 4 Gy. To estimate the endogenous indole-3-acetic acid (IAA), phenoxy acetic acid (PAA), and abscisic acid (ABA) levels, indirect ELISA was performed with the help of antibodies raised against each hormone. In samples at later stage, dose dependent response was apparent in PAA. Results showed that in vivo content of each hormone increased with radiation treatment except ABA.

Cytogenetic analysis of M2 plants after irradiation of cotton by thermal neutrons was performed in 56 families. In 40 plants of 27 M2 families, different abnormalities of chromosome pairing were found. These abnormalities were caused by primary monosomy, chromosomal interchange, and desynapsis. The presence of chromosome aberrations in some cases decreased meiotic index and pollen fertility. Comparison of the results of cytogenetics analysis, performed in M1 and M2 after irradiation, showed a nearly two-fold decrease in the number of plants with chromosomal aberrations in M2, as well as narrowing of the spectrum of these aberrations. The latter result is explained by the fact that some mutations are impossible to detect in subsequent generations because of complete or partial sterility of aberrant M1 plants. It was established that the most efficient radiation doses for inducing chromosomal aberrations in the present study were 15 and 25 Gy, since they affected survival and fertility of altered plant to a lesser extent.

Whole-genome radiation hybrid mapping has been applied extensively to human and certain animal species, but little to plants. We recently demonstrated an alternative mapping approach in cotton (Gossypium hirsutum L.), based on segmentation by 5-krad gamma-irradiation and derivation of wide-cross whole-genome radiation hybrids (WWRHs). However, limitations observed at the 5-krad level suggested that higher doses might be advantageous. Here, we describe the development of an improved second-generation WWRH panel after higher dose irradiation and compare the resulting map to the 5-krad map. The genome of G. hirsutum (n = 26) was used to rescue the radiation-segmented genome of G. barbadense (n = 26) introduced via 8- and 12-krad gamma-irradiated pollen. Viable seedlings were not recovered after 12-krad irradiation, but 8-krad irradiation permitted plant recovery and construction of a 92-member WWRH mapping panel. Assessment of 31 SSR marker loci from four chromosomes revealed that the 8-krad panel has a marker retention frequency of ca. 76%, which is approximately equivalent to the rate of loss in a low-dose animal radiation hybrid panel. Retention frequencies of loci did not depart significantly from independence when compared between the A and D subgenomes, or according to positions along individual chromosomes. WWRH maps of chromosomes 10 and 17 were generated by the maximum likelihood RHMAP program and the general retention model. The resulting maps bolster evidence that WWRH mapping complements traditional linkage mapping and works in cotton, and that the 8-krad panel complements the 5-krad panel by offering higher rates of chromosome breakages, lower marker retention frequency, and more retention patterns.

Super-weak luminescence of individual living cotton cells was investigated. This phenomenon was observed under an optical microscope using a replica-reprint technique in conjunction with living cotton cells. Gelatin solution was used for visualization of luminescence in a polymer film deposited on the cotton cells. No luminescence was generated in dead and very young plant cells (1 day after flowering) but maximal luminescence was detected from apical parts of cotton hairs in the early growth stage (4-6 days after flowering). Emitted luminescence had a cone-like form for different varieties of cotton plants. This indicates a focusing of radiation connected with morphological and structural features of the apical part of cotton cells at early stages of their evolution. The electromagnetic nature of cotton cell luminescence has been shown by experiments using photomultiplier (PEM) sensing of ultraviolet radiation. Insertion of a cotton seed-bud in darkness on a PEM window increased the dark current by 6-8%. Radiation flux from developing cotton hair is actually more intense, but through the PEM window only a small part of the radiation was detected., ((c) 2005 John Wiley & Sons, Ltd.)

Current conditions of 2-11 kJ m(-2) day(-1) of UV-B radiation and temperatures of >30 degrees C during flowering in cotton cultivated regions are projected to increase in the future. A controlled environment study was conducted in sunlit growth chambers to determine the effects of UV-B radiation and temperature on physiology, growth, development and leaf hyperspectral reflectance of cotton. Plants were grown in the growth chambers at three day/night temperatures (24/16 degrees C, 30/22 degrees C and 36/28 degrees C) and three levels of UV-B radiation (0, 7 and 14 kJ m(-2) day(-1)) at each temperature from emergence to 79 days under optimum nutrient and water conditions. Increases in main stem node number and the node of first fruiting branch and decrease in duration to first flower bud (square) and flower were recorded with increase in temperature. Main effects of temperature and UV-B radiation were significant for net photosynthetic rates, stomatal conductance, total chlorophyll and carotenoid concentrations of uppermost, fully expanded leaves during squaring and flowering. A significant interaction between temperature and UV-B radiation was detected for total biomass and its components. The UV-B radiation of 7 kJ m(-2) day(-1) reduced boll yield by 68% and 97% at 30/22 degrees C and 36/28 degrees C, respectively, compared with yield at 0 kJ m(-2) day(-1) and 30/22 degrees C. No bolls were produced in the three temperature treatments under 14 kJ m(-2) day(-1) UV-B radiation. The first-order interactions between temperature, UV-B radiation and leaf age were significant for leaf reflectance. This study suggests a growth- and process-related temperature dependence of sensitivity to UV-B radiation.

Increases in both atmospheric CO2 concentration ([CO2]) and ultraviolet-B (UV-B) radiation on the Earth's surface are features of current climate change patterns. An experiment was conducted in sunlit, controlled environment chambers known as Soil-Plant-Atmosphere-Research (SPAR) units to determine interactive effects of elevated [CO2] and UV-B radiation on leaf and canopy photosynthetic characteristics of cotton. Six treatments were comprised of two CO2 levels of 360 (ambient) and 720 (elevated) microL L(-1) and three levels of 0 (control), 8, and 16 kJ m(-2) d(-1) biologically effective UV-B radiation. Treatments were imposed for 66 days from crop emergence through three weeks after the first flower stage. Plants grown in elevated [CO2] had significantly greater leaf area, higher leaf and canopy net photosynthetic rates (PN), lower dark respiration rate (Rd), and lower light compensation point (LCP) than plants grown in ambient [CO2]. There was no difference in CO2 compensation point (gamma), maximum rate of Rubisco activity (Vcmax), or light-saturated rate of electron transport (Jmax) between ambient and elevated CO2 treatments. When plants were grown in 8 kJ m(-2) d(-1) UV-B radiation, most of the measured photosynthetic parameters did not differ from control plants. High UV-B (16 kJ) radiation, however, caused 47-50% smaller leaf area, 38-44% lower leaf PN, 72-74% lower Vcmax, and 61-66% lower Jmax compared to the control. There were no interactive effects of [CO2] and UV-B radiation on most of the photosynthetic parameters measured. From the results, it is concluded that decreased canopy photosynthesis due to enhanced UV-B radiation in cotton is associated with both smaller leaf area and lower leaf PN, and loss of Rubisco activity and electron transport are two major factors in UV-B inhibition of leaf PN.

The exploded bast, branch and stem of cotton stalk were degraded by alkalophilic Bacillus NT-19, with weight losses of 24%, 20% and 14%, respectively, after 14 d. Compared with a white-rot fungus (Phanerochaete chrysosporium), Bacillus NT- 19 preferentially degraded the non-cellulose components of cotton stem. The relative degree of crystallinity of bast fibers decreased by 8% and the middle lamella was partially removed from the fiber bundle by the Bacillus.

The temperature dependence of the relationship between the decline in activity of photosystem II (PSII) and a chlorophyll a fluorescence parameter combining the excitation pressure (1-qP) and efficiency of excitation energy capture by open PSII reaction centers in the light-acclimated state (Fv'/Fm') was investigated in cotton leaves. A formula for the prediction of PSII inactivation is proposed on the basis of the results obtained. By comparison of the predicted and actual levels of PSII photoinactivation, the rate of PSII recovery was estimated from chlorophyll a fluorescence parameters measured during the day for attached cotton leaves exposed to suboptimal morning temperatures in a greenhouse.

The karyotypes of biomorphologically abnormal cotton (Gossypium hirsutum L.) plants obtained in M2 after pollination with pollen irradiated at dose rates 10, 15, 20, and 25 Gy were studied. Various genomic and chromosomal mutations were detected in 57 M2 families. The primary monosomics isolated in M2 were found to be cytologically more stable and more viable, since they had higher meiotic indices, pollen fertility, and seed formation. In M2, a decrease in the number of plants with multiple karyotype aberrations and interchromosomal exchanges with high frequency of multivalent formation was observed. The multivalents had diverse patterns and types of chromosome segregation and translocation complexes. Their pollen fertility was higher than in translocants found in M1. Desynapsis often occurred in M2, including plants with chromosome deficiency or rearrangements. The variation in the number of univalents in various cells was found to result from different expression of synaptic genes. The results indicate stabilization of karyotypes, increase in cytologic stability and viability, and the absence of sterility in aberrant plants.

The effect of pollen irradiation at dose rates of 10, 15, 20, and 25 Gy on variability in cotton plants Gossypium hirsutum L. was studied. The modified plants showed a reduced fertility, mainly caused by chromosomal rearragements and genomic mutations during meiosis. The genomic mutations involved primary and tertiary monosomics, monotelodisomics, and a haploid plant. The decrease in meiotic index and pollen fertility in the cotton aneuploids was related not only to aberrations in chromosome pairing but also to genetic features of the original plants. It was found that heterozygosity for interchromosomal exchanges found in M1 plants resulted in the formation of multivalent associations of chromosomes of various forms and types of segregation from translocation complexes. Another result was high variability in pollen fertility. An increase in irradiation dose rate caused an increase in the number of translocants with a high frequency of quadrivalents. The results suggest that the great diversity of forms observed in M1 after pollination with irradiated pollen is determined, first, by elimination of some chromosomes or their arms or the whole paternal genotype and second, by interchromosomal rearrangements. The high variability in pollen fertility of translocants hampers using this trait as a marker of heterozygosity for exchanges in cotton.

Cotton (Gossypium hirsutum L.) crop, cultivated between 40 degrees N and 40 degrees S, is currently experiencing 2-11 kJ m-2 d-1 of UV-B radiation. This is predicted to increase in the near future. An experiment was conducted to study the effect of enhanced UV-B radiation on vegetative and reproductive morphology and leaf anatomy of cotton in sunlit, controlled environment chambers. From emergence to harvest, cotton plants were exposed to 0, 8 or 16 kJ m-2 d-1 of UV-B in a square wave approach for 8 h from 0800 to 1600 h. Changes in plant height, internode and branch length, mainstem node number, leaf area, length and area of petals and bracts, and anther number per flower were recorded. Epidermal cell and stomatal density, stomatal index, leaf thickness, and epidermal, palisade and mesophyll tissue thickness were also measured. Initial chlorotic symptoms on leaves turned into necrotic patches on continued exposure to enhanced UV-B. Exposure to high UV-B reduced both vegetative and reproductive parameters and resulted in a smaller canopy indicating sensitivity of cotton to UV-B radiation. Enhanced UV-B radiation increased epicuticular wax content on adaxial leaf surfaces, and stomatal index on both adaxial and abaxial leaf surfaces. Leaf thickness was reduced following exposure to UV-B owing to a decrease in thickness of both the palisade and mesophyll tissue, while the epidermal thickness remained unchanged. The vegetative parameters studied were affected only by high levels of UV-B (16 kJ m-2 d-1), whereas the reproductive parameters were reduced at both ambient (8 kJ m-2 d-1) and high UV-B levels. The study shows that cotton plants are sensitive to UV-B at both the whole plant and anatomical level.

The Gossypium hirsutum cv. Liaomian No. 9 were mutagenized by 60Co gamma ray, from which the mutant line Zhonghuzhi PI 935 (be called "PI 935" for short) was bred by family selection method. The PI 935 not only has some good traits (growing period, drought tolerance, lint color and fiber quality) similar to the original cultivar, but also has higher lint outturn and lint yield than that of the Liaomian No. 9. The PI 935 has been identified and regional tested in nine places times for four years in the southern Xinjiang Weiwuer autonomous region. It was shown that the PI 935 had the higher lint outtrn for the average 47.3% was ten-point percentage more than that of the check cultivars (Junmian No. 1 or Xinluzhong No. 5), the similar lint yield by and large and the growing period by five days later than that of the checks. The PI 935 was collected in the National Bank of Crop Germplasm (unified No. ZM 114274 and named "Zhonghuzhi PI 935").

The effects of different soil moistures and shading levels on stomatal conductance(Gs), net photosynthetic rates(Pn), transpiration and leaf water potential(LWP) of cotton (variety Zhongmian No. 23) grown in pots from the seedling to flower bud stages in summer noon were evaluated. We designed three shading levels: no-shading(CK), 75% shading (DN), 40% shading(SN); and three soil moistures; 85%-100% (high water, HW), 65%-85% (medium water, MW) and 45%-65% (low water, LW) of field water-bolding capacity. The Gs of DN and SN increased by 16.69% and 28.01% compared with CK at HW, respectively, while the Pn of DN and SN declined by 45.74% and 20.54%, respectively. The Gs of DN and SN enhanced by 28.86% and 23.28% compareds with CK at MW, respectively, while the Pn of DN and SN decreased by 31.97% and 1.64%, respectively. The Gs of CK, DN and Sn did not exhibit significant differences at LW, while Pn of DN and SN reduced by 46.22% and 13.45%, respectively. Significant difference in Gs did not exist between DN and SN at the same soil moisture, but there was significant difference in Pa between them (except at LW). It was suggested that Gs declined with the increasing of leaf-to-air vapor pressure difference (VPD) and showed weak correlation with Pn by regression. The combined effects of soil moistures and shading levels on LWP and transpiration rate were not significant. There was no significant difference in LWP and transpiration rate among three shading treatments. Contrasted to treatment CK, intercellular CO2 concentration (Ci) in DN and SN at HW, MW and LW increased significantly, except no apparent change of Ci in SN at MW.

Cotyledonary nodes taken alongwith shoot apex from seedlings of cotton (G. hirsutum) proliferated into shoots on nutrient agar medium supplemented with cytokinins. In the presence of optimal plant growth regulators, low light intensity enhanced the number of shoots initiated per explant in cotton. An average of 33.5 +/- 2.9 shoots were obtained from a single explant cultured for 8 weeks which is about four fold higher than the values reported in earlier protocols. The isolated shoots were rooted on nutrient agar medium supplemented with alpha-naphthalene acetic acid and transferred to soil after acclimatization. Regenerated plants were morphologically identical to the seed-germinated plants and were fertile.

In laboratory and field experiments, the effect of medium-wave (290-320 nm) UV-radiation (UV-B) on the build-up of photosynthetic pigments, growth and productivity of higher plants was investigated. It was found that UV-B of 5-9 W/m2 in intensity applied daily (at a daily dose of 15-20 kJ/m2) or singly (at a daily dose of 24 or 36 kJ/m2) inhibited the formation of chloroplast pigments. The pattern and magnitude of changes depended on the plant species and leaf age. The degree of photosynthetic changes and plant resistance to UV-radiation were closely correlated. In field experiments (daily irradiation with 0.6 W/m2 at a dose of 12-13 kJ/m2/day), UV-B suppressed the growth and yield of cotton and soybean plants. This exposure modified chloroplasts of soybean plants and inhibited their growth to a greater extent than that of cotton plants. The factors responsible for the species-related specificity of UV-B resistance of higher plants are discussed and approaches to its evaluation based on the pigment apparatus of photosynthesis are described.

Utilization of ionizing radiation for the sterilization purposes enables the sterilization of dressing materials in packed form together with the protecting packages. This procedure secures advantageous conditions for prolongation of storage time of manufactured articles in the sterile state. In this work the results of six years investigations dealing with the sterility of dressings sterilized by 60Co gamma-irradiation and packed in one--and multilayer packaging materials were shown. After sterilization those materials were storaged in various temperature conditions.

The irradiation of hospital linen contaminated with radioresistant microorganisms or hospital microflora with gamma radiation in a dose of 10 kGy ensures the reliable microbial decontamination of such linen. Cotton linen has been found capable of withstanding 15 irradiation cycles in a dose of 10 kGy.

According to ESR spectra of the radical - probe I it has been shown that there are two regions in cotton cellulose: ordered and disordered ones, pointing to inhibition and free rotation of the radical. 40 spin-labeled samples of cotton filaments and their mutants by the radicals II-IX chemically bound by the cellulose hydroxyl group were obtained. From ESR spectra strong inhibition of iminoxyl radical was established which was the evidenced of high rigidity of disordered regions of cellulose. Conformational changes of cotton cellulose grown from seeds exposed to different doses of gamma-irradiation.