Leaf Growth in Cotton (Gossypium hirsutum L.) 1. Growth in Area of Main-stem and Sympodial Leaves

A model is presented for growth of individual and successivemain-stem leaves of cotton, based on a series of indoor experimentsand data sets from the literature. Three variable parametersare used to describe individual leaf growth: relative growthrate of meristematic tissue (R¹), relative rate of approachof final area (R₂) and a ‘position parameter’ (t_0.5)which governs the transition from meristematic to extensiongrowth. Final area of a leaf does not occur in the model asa deterministic quantity but it is a result of the processesduring growth. The model generates successive mainstem leavesand sympodial leaves as an integrated system. Assimilate shortagesoccurring in the plant operate on R₁ leading to the characteristicchange of final leaf area along the mainstem. Gossypium hirsutumL., cotton, leaf growth, relative growth rate, meristematic tissue, extension growth, mathematical model     

Interference between Redroot Pigweed (Amaranthus retroflexus L.) and Cotton (Gossypium hirsutum L.): Growth Analysis

Redroot pigweed is one of the injurious agricultural weeds on a worldwide basis. Understanding of its interference impact in crop field will provide useful information for weed control programs. The effects of redroot pigweed on cotton at densities of 0, 0.125, 0.25, 0.5, 1, 2, 4, and 8 plants m^-1 of row were evaluated in field experiments conducted in 2013 and 2014 at Institute of Cotton Research, CAAS in China. Redroot pigweed remained taller and thicker than cotton and heavily shaded cotton throughout the growing season. Both cotton height and stem diameter reduced with increasing redroot pigweed density. Moreover, the interference of redroot pigweed resulted in a delay in cotton maturity especially at the densities of 1 to 8 weed plants m^-1 of row, and cotton boll weight and seed numbers per boll were reduced. The relationship between redroot pigweed density and seed cotton yield was described by the hyperbolic decay regression model, which estimated that a density of 0.20–0.33 weed plant m^-1 of row would result in a 50% seed cotton yield loss from the maximum yield. Redroot pigweed seed production per plant or per square meter was indicated by logarithmic response. At a density of 1 plant m^-1 of cotton row, redroot pigweed produced about 626,000 seeds m^-2. Intraspecific competition resulted in density-dependent effects on weed biomass per plant, a range of 430–2,250 g dry weight by harvest. Redroot pigweed biomass ha^-1 tended to increase with increasing weed density as indicated by a logarithmic response. Fiber quality was not significantly influenced by weed density when analyzed over two years; however, the fiber length uniformity and micronaire were adversely affected at density of 1 weed plant m^-1 of row in 2014. The adverse impact of redroot pigweed on cotton growth and development identified in this study has indicated the need of effective redroot pigweed management.     

Pattern of Nucleolar Growth in Differentiating Cotton Fibres (Gossypium hirsutum L.)

The nucleolar size in cotton fibres has been examined at earlystages of growth by light microscopy. The volumes of the nucleoliwere computed from the perimeters measured by means of a projectionmicroscope. The frequency distributions were normal at eachstage. The mean nucleolar volume increased rapidly, reacheda maximum around 10 d after anthesis and declined to a constantvalue around 20 d after anthesis. The nucleolar growth patternsof some prediction models have been compared with the in situobservations. This comparison suggests a simultaneous increasein nucleolar size in all fibres within a population. Therefore,the hypothesis that the size of the fibres is correlated withthe size of resident nucleoli, is favoured. Gossypium hirsutum, cotton fibre, nucleolus, cell differentiation     

Partitioning of Carbohydrates in Annual and Perennial Cotton (Gossypium hirsutum L.)

An analysis of the partitioning of carbohydrates in annual andperennial cotton was made to ascertain the distribution of assimilatesand constitution of reserves. Root/shoot dry matter ratio ishigh in perennial cotton and this plant shows a preferentialaccumulation of dry matter in roots corresponding to its adaptationto drought. Starch content is also higher in perennial cottonroots than in annual. It can be said that the earlier maturingthe cultivar, the lower the root/shoot ratio and the lower thestarch content. Nevertheless, at the whole plant level in annualcotton the starch content is highest in leaves where it is accumulatedbefore migration, and stem wood, and lowest in root and bark.While starch content in roots of annuals declines after 3 months,it is still increasing in perennials. Accumulation of carbohydratesas reserve material can be modified by selection and such selectionis accompanied by an increase in the activities of ß-amylasein exporting organs: leaves, woody tissue of the stem, and barkbut not in roots. Invertase activities were highest in leavesbut did not respond to selection. Non-irrigated cotton had ahigher activity of ß-amylase in leaves and stem woodcorresponding to the mobilization of reserve assimilates. Smallerincreases were observed in the activity of invertase. High yieldingannual cottons show a higher activity of ß-amylaseand invertase in leaves corresponding to a higher capacity ofassimilate transfer. Also a comparison was made from emergenceto 4 months of the partitioning of carbohydrates between leaf,stem and roots in annual and perennial cotton. In conclusionperennial cotton apparently owes its drought resistance to apartitioning of assimilates that favours the growth of the rootsystem and the accumulation of starch reserves in roots. Key words: Gossypium hirsutum L, carbohydrates, partitioning     

Morphological and Physiological Responses of Cotton (Gossypium hirsutum L.) Plants to Salinity

Salinization usually plays a primary role in soil degradation, which consequently reduces agricultural productivity. In this study, the effects of salinity on growth parameters, ion, chlorophyll, and proline content, photosynthesis, antioxidant enzyme activities, and lipid peroxidation of two cotton cultivars, [CCRI-79 (salt tolerant) and Simian 3 (salt sensitive)], were evaluated. Salinity was investigated at 0 mM, 80 mM, 160 mM, and 240 mM NaCl for 7 days. Salinity induced morphological and physiological changes, including a reduction in the dry weight of leaves and roots, root length, root volume, average root diameter, chlorophyll and proline contents, net photosynthesis and stomatal conductance. In addition, salinity caused ion imbalance in plants as shown by higher Na⁺ and Cl⁻ contents and lower K⁺, Ca²⁺, and Mg²⁺ concentrations. Ion imbalance was more pronounced in CCRI-79 than in Simian3. In the leaves and roots of the salt-tolerant cultivar CCRI-79, increasing levels of salinity increased the activities of superoxide dismutase (SOD), ascorbate peroxidase (APX), and glutathione reductase (GR), but reduced catalase (CAT) activity. The activities of SOD, CAT, APX, and GR in the leaves and roots of CCRI-79 were higher than those in Simian 3. CAT and APX showed the greatest H₂O₂ scavenging activity in both leaves and roots. Moreover, CAT and APX activities in conjunction with SOD seem to play an essential protective role in the scavenging process. These results indicate that CCRI-79 has a more effective protection mechanism and mitigated oxidative stress and lipid peroxidation by maintaining higher antioxidant activities than those in Simian 3. Overall, the chlorophyll a, chlorophyll b, and Chl (a+b) contents, net photosynthetic rate and stomatal conductance, SOD, CAT, APX, and GR activities showed the most significant variation between the two cotton cultivars.     

Conditioning of Fasciation by Gibberellin and Genotype in Cotton (Gossypium hirsutum L.)

The round-leafed mutant cotton line L-501 developed fasciation of the upper stem when field grown in Central Asia. Fasciation co-segregated with the mutant gene for round leaves In. ^l Fasciation developed at the flowering stage, but removal of floral buds did not prevent fasciation. Fasciation in L-501 could be inhibited by the gibberellin (GA) biosynthesis inhibitor chlorocholine chloride or by fusicoccin. GA₃ application in the field induced fasciation in the mutant's parental line L-463, which has five-lobed leaves and does not normally develop fasciation. Fasciation did not develop in either line, even after GA₃ treatment, in UK glasshouse conditions. Received June 17, 1998; accepted January 25, 1999     

Effect of Far Red Light on Root Growth and on Xylem Sap in Cotton (Gossypium hirsutum L.)

Far red light given before darkness highly increased droughtresistance of cotton plants. There was higher stomatal resistancein leaves resulting in a lower transpiration rate. The aim ofthis work was to examine the effect of far red light on rootgrowth and its effect on water transfer measured by analysisof xylem sap obtained after cutting the hypocotyl. Short-termand long-term treatments of far red light were used. In thepresence of far red light, the amount of xylem sap decreasedwhile root resistance increased. Qualitative analysis of thexylem sap indicated an increase of amino acid content and analteration of potassium flux. Calcium flux was not significantlymodified. The change in potassium content of xylem sap is discussedwith regard to turgor and drought resistance. (Received June 9, 1984; Accepted October 8, 1985)     

棉花高频体细胞胚胎发生及再生体系建立

棉花的体细胞胚胎发生率低,限制了转基因棉花的发展。为了扩大可再生棉花的基因型,发展新疆优质棉花的特点,以新疆的主要栽培品种新陆早33为材料,以下胚轴为外植体,使用葡萄糖,麦芽糖作为主要碳源,用Phytagel固化,对不同激素的浓度组合和培养条件进行探索,对棉花胚性愈伤的诱导到体细胞胚胎的发生阶段进行优化,体细胞胚胎成熟以后进行萌发培养可以获得正常的植株。通过试验证明,有利于棉花的愈伤组织生长的激素浓度为KT 0.1 mg/L,2,4-D 0.1 mg/L,下胚轴的中部诱导愈伤形态最好。体细胞胚胎发生阶段以KT,IBA组合,以低盐培养基进行子叶胚的成苗,建立了再生体系。     

棉花MADS框蛋白基因(GhMADS1)的克隆

作为转录因子,MADS框蛋白基因在植物花器官发育中有着重要的功能。为研究棉花花器官发育的分子机理,以棉花花器官突变体CHV1(cotton homeotic variant)和徐州142正常植株为材料,利用棉花EST数据库资料,通过EST序列整合,从陆地棉徐州142花蕾中克隆出一个MADS框蛋白的编码区段,GenBank登录号为AF538965。该片段(GhMADS1)长713bp,包含一个711bp的开放阅读框,推导的氨基酸序列(236个氨基酸)与葡萄、烟草、矮牵牛、拟南芥和金鱼草等的AGL2组MADS框蛋白有很高的序列相似性。系统进化分析同样将GhMADS1基因归人AGt2组MADS框蛋白。RT-PCR分析显示,该基因在陆地棉的花瓣、雄蕊、胚珠和纤维中表达,特别是在花瓣中表达量最高,而在根、茎、叶等营养器官和棉花同源异型突变体CHV1(所有花器官均变为苞叶状叶性器官)的变异花蕾中不表达。这些结果说明GhMADS1基因可能在棉花花器官发育中有着重要的功能。     

两个棉花Rac蛋白基因的克隆与表达分析

为研究棉花纤维起始和伸长的分子机理,在棉花纤维EST序列分析的基础上,从棉花纤维中扩增并克隆了2个棉花Rac蛋白的cDNA基因,分别命名为GhRacA和GhRacB。GhRacA cDNA长959bp,推测的编码蛋白包含211个氨基酸。GhRacB cDNA长920bp,编码195个氨基酸的蛋白。GhRacA和GhRacB蛋白均含有GTP／GDP结合和激活区域、Effector区和碱性氨基酸区。GhRacB的C末端有保守的异戊烯基化位点CSIL,而GhRacA没有明显的异戊烯基化位点。序列比较分析表明,GhRacA和GhRacB是2个新的棉花Rac蛋白。RT-PCR分析表明,GhRacA和GhRacB在根、下胚轴、茎、叶和纤维中都有表达,但均在棉花纤维起始和伸长时期有优势表达,推测2个基因在棉花纤维的早期发育中可能有重要的功能。     

棉花体细胞增殖和胚胎发生中的细胞程序性死亡

棉花组织培养中愈伤组织褐化可能与细胞程序性死亡(PCD)有关.对棉花组培中不同时期的愈伤组织DNA进行琼脂糖电泳,观察到:仅在第一次愈伤组织继代后10 d左右和愈伤组织第一次继代到分化培养基中培养10 d左右,愈伤组织的DNA产生了180 bp左右的片断或其整数倍片断大小的DNA带,呈DNA梯(DNA ladder)状电泳,说明在这两个时期PCD达到了高峰.在这两次PCD高峰后1周均出现愈伤组织大规模的褐化死亡.显微镜观察到第一次PCD发生高峰的愈伤组织存在许多管状、内含物少的细胞,这些细胞分布在愈伤组织的边缘和内部;第二次PCD发生高峰观察到体细胞胚胎分化、PCD细胞的木栓化和水渍化.对体细胞胚胎分化时期的原生质体进行荧光染色(DAPI),荧光显微镜下观察到发生细胞程序性死亡的细胞核浓缩、染色质凝聚、结块、边缘化和形成PCD小体.     

Comparative Epidermal Ultrastructure of Cotton (Gossypium hirsutum L.) Leaf, Bract and Capsule Wall

Cotton leaves are more physiologically active than the bractand the capsule wall of the fruiting structures. To elucidatethe disparities in their physiological behaviour, epidermalcell density, stomatal index, stomatal size, trichome densityand type, and epicuticular wax ultrastructure of cotton leaf,bract and capsule wall were delineated using scanning electronmicroscopy (SEM). The epidermal cells of the outer periclinalwalls on both surfaces of the leaf and bract were raised andconvex. Conversely, the capsule wall epidermal cells were polygonalwith flat outer periclinal walls. The stomatal complex in theleaf and bract was paracytic, whereas in the capsule wall thestomatal complex was anomocytic. The adaxial and abaxial stomataof the leaf were coplanar to the epidermal surface, as opposedto the raised adaxial stomata on the bract. On the contrary,the stomata on the capsule wall surface appeared to be slightlysunken. Furthermore, the capsule wall stomata were larger thanthe stomata on either surface of both the leaf and the bract.The stomatal index was greater on the abaxial surfaces of theleaf and the bract (18.4 and 9.4, respectively) than their correspondingadaxial surfaces (14.4 and 4.7, respectively). Leaves had thehighest stomatal index followed by the bract and the capsulewall. The indumentum consisted of glandular and nonglandulartrichomes, the density of which was greater on the abaxial surfacesthan on the adaxial surfaces of the leaf and bract. The capsulewall indumentum lacked nonglandular trichomes. Epicuticularwax occurred in the form of striations. However, the striationpattern varied among the organs. This study clearly illustratesmorphological disparities in the epidermal features of leaf,bract and capsule wall, helping to explain their physiologicaldivergence. Copyright 2000 Annals of Botany Company Gossypium hirsutum, epicuticular wax, raised stomata, scanning electron microscopy, stomatal index, trichomes     

根癌农杆菌介导的转aroAM12基因棉花植株的草甘膦抗性

以中棉35无菌苗下胚轴为外植体,采用农杆菌介导法将含有通过基因优化技术获得的草甘膦抗性突变基因aroAM12导入棉花中.以aroAM12为选择标记,利用草甘膦直接筛选获得65棵再生植株.PCR和Southerablot分析表明,经过草甘膦筛选出的To代植株均整合有aroAM12基因.Western blot分析表明整合进的aroAM12基因得到了有效表达,且不同植株之间的表达不尽相同.大棚喷洒的实验结果表明To代转化植株具有很高的草甘膦抗性.对T1代棉花的草甘膦抗性遗传分析表明,aroAM12基因以孟德尔方式遗传.     

An Efficient Agrobacterium-Mediated Genetic Transformation Using Embryonic Axis in Cotton (Gossypium hirsutum L.)

Russian Journal of Plant Physiology - Agrobacterium-mediated genetic transformation approach allows for introducing novel genes in cotton (Gossypium hirsutum L.). Development of efficient...     

启动子诱捕在棉花基因组中的功能分析

利用根癌农杆菌介导的遗传转化,将启动子诱捕（Promoter trapping）元件插入到棉花基因组,获得141个独立的转化子,其中97％的转化子经PCR扩增为阳性。不同组织中GUS基因的表达频率为：根部48％,茎的微管组织9．2％,叶5．2％,花51％;同时检测了不同植株中GUS基因的表达模式,发现GUS基因在不同株系的植株间的表达模式呈现较大的差异,有些植株中GUS基因是组织特异表达,有些则是器官特异表达,有些则在多个器官中均有表达。所建立的启动子诱捕系统中的GUS基因高频率、多模式和时空特异性表达为分离基因及其调节序列、开展功能基因组研究奠定了坚实的基础。     

Molecular Cloning and Characterization of the PsbP Domain Protein 1 Gene (GhPPD1) in Cotton (Gossypium hirsutum L.)

As a member of the PsbP superfamily in plants, the PsbP protein is essential for the water splitting reaction in photosynthesis. PsbP-like proteins (PPLs) are required for the repair of photodamaged photosystem II (PSII) under high-intensity light and the accumulation of chloroplast NADPH dehydrogenase (NDH). However, to date, studies on PsbP domain proteins (PPDs) are rather limited with literature reported on only PPD5 and PPD6. Other PPDs have not been studied yet. In this study, a cotton PsbP domain protein 1 gene (GhPPD1, GenBank accession no. HQ404251) encoding the PPD1 protein was cloned by rapid amplification of complementary DNA (cDNA) ends-polymerase chain reaction. The full-length cDNA is 951 bp and encodes an open reading frame of 257 amino acids with deduced molecular weight of 29 kDa. The GhPPD1 protein shared 77–86 % identity at the amino acid level with PPD1 isolated from Populus trichocarpa, Ricinus communis, Vitis vinifera, Glycine max, and Arabidopsis thaliana. The corresponding genomic DNA containing three exons and two introns was isolated and analyzed. The 5′ flanking region was also analyzed to identify a group of putative cis-acting elements. DNA gel blot analysis revealed that the GhPPD1 gene has two to five copies in the cotton genome. Additionally, real-time PCR analysis revealed that GhPPD1 was expressed in cotton leaves, anthers, and stems, and its expression level in leaves was much higher than those in anthers and stems. It was minimally expressed in other tissues. On the basis of these results, we propose that GhPPD1 is not only associated with photosynthesis but also related to pollen activity and male fertility.     

Ontogenic Changes in Epicuticular Wax and Chloroplast Integrity of a Cotton (Gossypium hirsutum L.) Leaf

The progressive decline in cotton leaf photosynthesis with season could be accounted for by gaining an insight into ontogenic changes in chloroplast integrity and epicuticular wax ultrastructure. Therefore, the sequence of ultrastructural changes in chloroplast and epicuticular wax morphology were probed in 10-, 20-, 40-, and 60-d-old cotton (Gossypium hirsutum L.) leaves using electron microscopy. Scanning electron microscopy illustrated that the epicuticular wax on the periclinal walls of the convex epidermal cells occurred as striations and persisted as such during the course of leaf aging. The degree of wax spread, however, increased as the leaf progressed towards senescence. Transmission electron microscopy revealed that a 20-d-old photosynthetically active leaf possessed healthy chloroplasts (6.8 m long and an area of 9.7 m²) with absolute membrane integrity depicted by large appressed grana stacks of thylakoids interconnected by non-appressed stroma lamellae. The thylakoid membrane network was oriented parallel to the long axis of the chloroplast and a few small plastoglobuli (1.85 m²) scattered in the stroma. Conversely, membrane integrity was lost with leaf age after 20 d as evidenced by disruption of the grana and stroma lamellae. Concurrent with the membrane damage, extensive occlusion of chloroplast by several large spherical plastoglobuli (5.68 m²) occurred, the rate of occlusion increased with leafage distending the chloroplast as evidenced by proliferation of its cross-sectional area (12.8 m²). Of particular interest was the finding that the plastoglobuli ensued through the chloroplast envelope into the cytoplasm. The progressive loss of chloroplast membrane integrity coupled with increased leaf waxiness may have limited photosynthetic activities of cotton leaves during senescence.     

陆地棉原生质体高频率分裂及植株再生

取陆地棉品种（系）３１１８、９５５４和晋棉４号种子无菌苗的下胚轴诱导的愈伤组织,从中挑选具有分化能力的黄色颗粒状愈伤组织,建立胚性细胞悬浮培养系。以纤维素酶和离析软化酶组成的酶液,由细胞悬浮培养物游离原生质体。采用含低融点脂糖的Ｋ３基本培基包埋原生质体的培养方式,获得愈伤组织。以液体－固体－液体轮回培养法改良晋棉４号的细胞悬浮系,原生质体的植板率从２％左右提高到９％以上。在原生质体再生愈伤组织的继     

Osmotic Adjustment in Cotton (Gossypium hirsutum L.) Leaves and Roots in Response to Water Stress

The relative magnitude of adjustment in osmotic potential (ψ_s) of water-stressed cotton (Gossypium hirsutum L.) leaves and roots was studied using plants raised in pots of sand and grown in a growth chamber. One and three water-stress preconditioning cycles were imposed by withholding water, and the subsequent adjustment in solute potential upon relief of the stress and complete rehydration was monitored with thermocouple psychrometers. Both leaves and roots exhibited a substantial adjustment in ψ_s in response to water stress with the former exhibiting the larger absolute adjustment. The osmotic adjustment of leaves was 0.41 megapascal compared to 0.19 megapascal in the roots. The roots, however, exhibited much larger percentage osmotic adjustments of 46 and 63% in the one and three stress cycles, respectively, compared to 22 and 40% in the leaves in similar stress cycles. The osmotically adjusted condition of leaves and roots decreased after relief of the single cycle stress to about half the initial value within 3 days, and to the well-watered control level within 6 days. In contrast, increasing the number of water-stress preconditioning cycles resulted in significant percentage osmotic adjustment still being present after 6 days in roots but not in the leaves. The decrease in ψ_s of leaves persisted longer in field-grown cotton plants compared to plants of the same age grown in the growth chamber. The advantage of decreased ψ_s in leaves and roots of water-stressed cotton plants was associated with the maintenance of turgor during periods of decreasing water potentials.