The combined effect of soil salinity and CCC on dry matter accumulation and yield of wheat plants

The rise in soil salinity level tended to decrease shoot dry weight, and, grain yield per plant and, to some extent, weight of I grain. This effect was usually more pronounced in the presence of CCC. On the other hand, the shoot dry weight was increased by CCC in salinity absence but the reverse at 0.8 % salinization degree. The grain yield per plant was raised by CCC in the presence or absence of salinity, particularly in the latter case. The dry matter accumulation in the shoot system (at earing stage) rather than grain yield tended to be much more affected, whether regarding the negative response to salinity or the positive one to CCC.     

Experiments with CCC on wheat: effects of spacing, nitrogen and irrigation

In experiments with spring and winter wheat at Rothamsted and Woburn during 4 years CCC increased yield at close spacing (4 in) (10 cm) more than at usual spacing (8 in) (20 cm), but there was no interaction between spacing and yield. Some experiments tested up to 2·4 cwt/acre (300 kg/ha) N to see whether yields continued to increase with more than usual amounts of N, when CCC prevented lodging. There was no evidence of this. When a short dry spell occurred at ear emergence, yield of spring wheat was increased by 6 cwt/acre (750 kg/ha) by CCC and 10 cwt (1250 kg) by irrigation. CCC probably improves yield in these conditions because the larger root system it causes enables more ear-bearing shoots to survive. CCC increases yield in two ways, either by increasing ears or grain per ear. In an unlodged crop CCC usually makes the grains smaller, but by preventing lodging it can also increase size. Usually CCC decreases the leaf area per shoot. The flag leaf may be smaller, unchanged or larger than those of untreated plants. There was no obvious connexion between flag-leaf area and grain yield; when CCC decreased flag-leaf area duration by 25 %, grain yield was unchanged. The results suggest that using CCC gives a more than even chance of a profitable yield increase.     

24-表油菜素内酯和盐度对浒苔生长和生理活性的影响

为探讨低温条件下外源植物激素和盐度变化对浒苔光合生理的影响,本文选取浒苔为供试材料,研究24-表油菜素内酯和盐度对其生长、光合色素、叶绿素荧光参数、抗氧化活性和可溶性蛋白含量的影响.结果表明: 与正常盐度(近岸海水盐度为25)相比,浒苔的生长在盐度10处理下显著增加,增幅为45.9%,但在盐度5处理下显著降低.盐度5处理的浒苔比其他盐度处理具有较高的Chl a和可溶性蛋白.24-表油菜素内酯(0.2 mg·L^-1)的加入显著抑制了浒苔的生长,尤其在盐度25处理下,浒苔呈现负增长的趋势,并大量释放孢子(配子),有效光化学效率、超氧化物歧化酶酶活性和可溶性糖含量明显降低,但可溶性蛋白含量显著增加.即在温度15 ℃条件下,可通过适当降低盐度促进浒苔的生长;在盐度25条件下,可通过添加24-表油菜素内酯促进孢子(配子)释放,为浒苔的大规模养殖提供原材料.     

Effect of two plant growth retardants on steviol glycosides content and antioxidant capacity in Stevia (Stevia rebaudiana Bertoni)

Two greenhouse experiments were conducted to study the effect of two plant growth retardants, Chlorocholine chloride (CCC) and Paclobutrazol (PBZ), on growth, Steviol glycosides (SVglys) content and antioxidant capacity in Stevia (Stevia rebaudiana Bertoni). Five concentrations of CCC (0, 250, 500, 750 and 1,000 ppm) and PBZ (0, 6, 12, 18 and 24 ppm) with three replications were applied to Stevia plants as treatments based on completely randomized design. CCC was sprayed on Stevia shoots, but PBZ was applied as a drench. The obtained results showed that CCC reduced plant height but improved leaf and stem dry weight, especially with 750 ppm concentration. Total SVgly content and consequently SVglys yield were significantly reduced by CCC application, and 1,000 ppm of CCC concentration was more effective than other treatments. PBZ had no effect on Stevia height while it significantly enhanced stem and dry weight at 12 ppm. Moreover, PBZ remarkably increased total SVglys contents, SVglys yield, and Rebaudioside A/Stevioside ratio. Total antioxidant capacity significantly varied with CCC and PBZ and the highest activity was obtained with 1,000 and 12 ppm of CCC and PBZ, respectively. The results of these experiments indicated that, although CCC and PBZ are plant growth retardants and act as anti-gibberellins, only CCC reduced plant height and SVglys production in Stevia. On the contrary, PBZ at 12 ppm concentration, improved Stevia growth, SVglys production, and antioxidant capacity.     

Caffeic acid decreases salinity-induced root nodule superoxide radical accumulation and limits salinity-induced biomass reduction in soybean

Caffeic acid (3,4-dihydroxycinnamic acid; CA) is a cinnamic acid occurring naturally in a variety of plant species. In this study, the effects of caffeic acid (100 μM caffeic acid) on soybean root nodule superoxide content, cell viability and superoxide dismutase (SOD; EC 1.15.1.1) activity were evaluated in the presence and absence of salinity stress (imposed by application of 70 mM NaCl), along with the effects of CA on growth of soybean in the presence or absence of salinity. Treatment with CA caused a decrease in superoxide content, enhanced cell viability and SOD activity, with changes in SOD activity accounted for by increased activity of two manganese SOD isoforms and one copper/zinc SOD isoform. Furthermore, CA improved soybean growth under salinity but reduced soybean biomass in the absence of salinity. We suggest that CA improves soybean salinity stress tolerance, possibly via signals that regulate accumulation of reactive oxygen species (ROS) during salinity stress.     

Isolation of an RD-114-Like Oncornavirus from a Cat Cell Line

A clone of cells derived from a continuous line of cat cells (CCC) spontaneously produced an RNA C-type virus (CCC virus) which did not have the group-specific antigen of the standard strains of feline leukemia viruses but did have that of the RD-114 virus. Single-hit infection of a virus yielding CCC cell with only the feline leukemia virus pseudotype of murine sarcoma virus [MSV(FeLV)] resulted in the release of a pseudotype of MSV coated with the CCC virus envelope. Host range, transmission of virus, helper functions, interference properties, and specific neutralization showed that the CCC and the RD-114 isolates as well as their respective MSV pseudotypes are closely similar if not identical. Parental, virus-negative cells frozen before the existence of RD-114 were chemically induced to yield CCC-like virus de novo. Infection of susceptible human cells with the chemically induced virus resulted in interference with the CCC virus pseudotype of MSV but not with the FeLV pseudotype of MSV.     

Proline overproduction in cells of the green alga Nannochloris bacillaris resistant to azetidine-2-carboxylic acid

Abstract Cells of N. bacillaris have been selected that are resistant to the toxic proline analogue azetidine-2-carboxylic acid (A2C) in 7% artificial seawater (ASW). This phenotype is stable in the absence of selection pressure. A2C resistance at low salinity was demonstrated to be due to an overproduction of proline in these cells, while levels of other amino acids were unaffected. Both wild-type and A2C-resistant cells respond to growth in high salinity media (100% ASW, 200% ASW) by accumulation of proline, but proline levels at all salinities are higher in the A2C-resistant cells than in the wild-type. Proline overproduction in the A2C-resislant cells did not affect fluctuations in the levels of other salinity-dependent solutes, such as homarine. A mutant with this level of specificity over a wide range of water potentials has not been reported for other plants and algae. Both the wild-type and A2C-resistant cells were able to grow over the entire salinity range tested (7%-300% ASW). However, the A2C-resistant cells showed a lower division rate than the wild-type in 300% ASW, and yield of A2C-resislant cells was lower than yield of wild-type cells at the salinity extremes (7% ASW, 300% ASW). The response or wild-type and A2C-resistant cells to rapid increases in salinity were similar for both growth and photosynthesis. The presence of a constitutive high level of proline in the A2C-resistant cell line did not confer any obvious increased tolerance to salinity shocks, indicating that there are other important factors in the biochemical adaptation to salinity in these cells.     

Different effects of chlormequat on chlorophyll,protein and yield in cotton grown under varying water regimes

Summary Cotton plants grown under water stress conditions showed significant decreases in yield, though only slight decreases in protein N as well as in chlorophyll content were detected. Chlormequat (CCC) application minimized the decreases in yield and caused significant increases in both protein N and chlorophyll contents. It is concluded that changes induced by CCC in cotton yield are independent from those occurred in chlorophyll and protein N contents.     

Grain yield and quality of wheat as affected by chlormequat (2-chloroethyl-trimethyl ammonium chloride)

Three field experiments studying the effect of chlormequat (CCC) on the grain yield of spring wheat and the quality of the grain for baking purposes were made. In the first, CCC applied as a spray during the stage of rapid internode elongation proved more successful than application as a mixture with superphosphate drilled with the seed at sowing. Both methods prevented lodging and the depression of yield which occurred in the control plots. In the other two experiments the sole method of CCC application was by spraying.
In all three experiments CCC-treated plots had more ears per unit area and grains per ear than control plots; the one exception being at the lowest plant density derived from a seeding rate of 24 kg/ha. CCC helped prevent weather damage to the grain and as a result baking performance of the flour from treated plots was superior to that from the untreated plots.     

Mixed Compound of DCPTA and CCC Increases Maize Yield by Improving Plant Morphology and Up-Regulating Photosynthetic Capacity and Antioxidants

DCPTA (2-diethylaminoethyl-3, 4-dichlorophenylether) and CCC (2-chloroethyltrimethyl- ammonium chloride) have a great effect on maize growth, but applying DCPTA individually can promote the increase of plant height, resulting in the rise of lodging percent. Plant height and lodging percent decrease in CCC-treated plants, but the accumulation of biomass reduce, resulting in yield decrease. Based on the former experiments, the performance of a mixture which contained 40 mg DCPTA and 20 mg CCC as active ingredients per liter of solution, called PCH was tested with applying 40mg/L DCPTA and 20mg/L CCC individually. Grain yield, yield components, internode characters, leaf area per plant, plant height and lodging percent as well as chlorophyll content, chlorophyll fluorescence, enzymatic antioxidants, membranous peroxide and organic osmolyte were analyzed in two years (2011 and 2012), using maize hybrid, Zhengdan 958 (ZD 958) at density of 6.75 plants m^-2. CCC, DCPTA and PCH were sprayed on the whole plant leaves at 7 expanded leaves stage and water was used as control. Compared to control, PCH significantly increased grain yield (by 9.53% and 6.68%) from 2011 to 2012. CCC significantly decreased kernel number per ear (by 6.78% and 5.69%) and thousand kernel weight (TKW) (by 8.57% and 6.55%) from 2011 to 2012. Kernel number per ear and TKW increased in DCPTA-treated and PCH-treated plants, but showed no significant difference between them. In CCC-treated and PCH-treated plants, internode length and plant height decreased, internode diameter increased, resulting in the significant decline of lodging percent. With DCPTA application, internode diameter increased, but internode length and plant height increased at the same time, resulting in the augment of lodging percent. Bending strength and puncture strength were increased by applying different plant growth regulators (PGRs). In PCH-treated plants, bending strength and puncture strength were greater than other treatments. Compared to control, the bending strength of 3rd internode was increased by 14.47% in PCH-treated plants in 2011, increased by 18.40% in 2012, and the difference was significant. Puncture strength of 1st, 3rd and 5th internode was increased by 37.25%, 29.17% and 26.09% in 2011 and 34.04%, 25% and 23.68% in 2012, compared to control. Leaf area and dry weight per plant reduced significantly in CCC-treated plants, increased in DCPTA-treated and PCH-treated plants from 2011 to 2012. Chlorophyll content and chlorophyll fluorescence improved with CCC and DCPTA application. Due to the additive effect of DCPTA and CCC, PCH showed the significant effect on chlorophyll content and chlorophyll fluorescence. Compared to control, total enzyme activity (SOD, POD, CAT, APX and GR) and soluble protein content increased, malonaldehyde (MDA) and hydrogen peroxide (H₂O₂) content reduced in PCH-treated plants. The transportation of soluble sugar from leaf to kernel improved significantly at the late silking stage. The research provided the way for the further use of DCPTA and CCC into the production practice.     

Bracteoles affect germination and seedling establishment in a Mediterranean population of Atriplex portulacoides

The germination and subsequent seedling establishment of Atriplex portulacoides from a population in SW Spain were investigated in response to the presence or absence of attached bracteoles, at a range of NaCl concentrations (0–6%). Increasing salinity reduced both the final germination percentage and the speed of germination. The presence of bracteoles greatly inhibited germination and this effect was more marked with increasing salinity; bracteoles completely inhibited germination at salinities higher than 2%. The effects of salinity were substantially reversible, as cumulative germination after transfer of ungerminated seeds to distilled water was similar in all salinity treatments. This enforced dormancy could serve to prevent germination of floating fruits during dispersal in seawater. However, after transfer to distilled water the germination of seeds with bracteoles was still significantly lower than those without them, as a result of both higher dormancy and lower viability (as revealed by tetrazolium testing). Bracteoles thus also appear to enforce some physical dormancy. Seedlings derived from seeds with bracteoles demonstrated higher survival rates in fresh water than those derived from seeds without bracteoles but at 2% salinity there was no difference, and at higher salinities no seedlings of either type survived.     

Influence of gibberellic and abscisic acids and the growth retardant,CCC, upon plastid development

Summary Gibberellic acid (GA₃) enhances ultrastructural morphogenesis of plastids in greening cereals whilst abscisic acid (ABA) and CCC have the reverse effect over a shorter period. GA₃ application counteracts the ABA and CCC inhibition of membrane development and, over longer periods of greening, the fastest rate of chloroplast development is shown in the presence of both GA₃ and ABA. Experiments with isolated etioplasts show that the ABA inhibition of development also occurs and can be counteracted with GA₃ treatment but no individual enhancement of plastid morphogenesis by GA₃ was detected.Ribulose 1,5-diphosphate carboxylase (RuDPC) acitvity was also increased with applications of GA₃ and reduced with ABA treatment. The initial levels of RuDPC activity in the presence of CCC were concentration dependant; high in 10^-3 M CCC and low in 10^-6 M CCC but activity returned to normal levels after CCC application was stopped. Experiments with isolated etio-chloroplasts gave similar results but levels of RuDPC activity declined rapidly in both illuminated and un-illuminated incubated suspensions of intact etioplasts.     

Identification and functional characterization of cation-chloride cotransporters in plants

Chloride (Cl(-)) is an essential nutrient and one of the most abundant inorganic anions in plant tissues. We have cloned an Arabidopsis thaliana cDNA encoding for a member of the cation-Cl(-) cotransporter (CCC) family. Deduced plant CCC proteins are highly conserved, and phylogenetic analyses revealed their relationships to the sub-family of animal K(+):Cl(-) cotransporters. In Xenopus laevis oocytes, the A. thaliana CCC protein (At CCC) catalysed the co-ordinated symport of K(+), Na(+) and Cl(-), and this transport activity was inhibited by the 'loop' diuretic bumetanide, a specific inhibitor of vertebrate Na(+):K(+):Cl(-) cotransporters, indicating that At CCC encodes for a bona fide Na(+):K(+):Cl(-) cotransporter. Analysis of At CCC promoter-beta-glucuronidase transgenic Arabidopsis plants revealed preferential expression in the root and shoot vasculature at the xylem/symplast boundary, root tips, trichomes, leaf hydathodes, leaf stipules and anthers. Plants homozygous for two independent T-DNA insertions in the CCC gene exhibited shorter organs such as inflorescence stems, roots, leaves and siliques. The elongation zone of the inflorescence stem of ccc plants often necrosed during bolt emergence, while seed production was strongly impaired. In addition, ccc plants exhibited defective Cl(-) homeostasis under high salinity, as they accumulated higher and lower Cl(-) amounts in shoots and roots, respectively, than the treated wild type, suggesting At CCC involvement in long-distance Cl(-) transport. Compelling evidence is provided on the occurrence of cation-chloride cotransporters in the plant kingdom and their significant role in major plant developmental processes and Cl(-) homeostasis.     

Salinity tolerance in <Emphasis Type="Italic">Daphnia magna</Emphasis>: characteristics of genotypes hatching from mixed sediments

The hatching of diapausing eggs is a means of temporal dispersal that can provide populations with genotypes adapted to different environments. In a salinity-variable shallow lake, we predicted that the mixing of different age-classes of eggs in the sediment may yield genotypes with different salinity optima. The alternative would be the absence of local adaptation and the presence of a homogenous population of salt-tolerant genotypes with high phenotypic plasticity. We tested these alternatives by isolating Daphnia magna resting eggs from different sediment depths, exposing them to hatching cues at different salinity levels and measuring the performance of hatched individuals. Results revealed a homogeneous sediment with generally broad-tolerance genotypes and some genotypes with low salt tolerance, which supports the second hypothesis. However, the disturbed character of the sediment hampered historical reconstruction. The absence of local adaptation in the diapausing egg bank may be the result of various scenarios in the response of D. magna populations to severe salinity changes in the lake.     

Combined effect of salinity and excess boron on plant growth and yield

Plants are likely to be affected by simultaneous salinity and boron (B) toxicity stresses due to exposure to soils with high levels of naturally occurring salinity and B, or due to irrigation with water containing high levels of salts, including B. Inadequate information regarding the response of plants to the combination of excess B and salinity on plant growth and yield is available, and there is no consensus concerning mutual relations between salinity stress and B toxicity. Growth and yield of bell pepper (Capsicum annuum L.) were measured at different B and salinity levels in two greenhouse experiments. The results from these experiments and from published data for wheat, tomato and chickpea were analyzed according to the Abbott method to define the combined effect of B and salinity on plant growth and yield. Application of the Abbott method for the experiments on peppers generally implied an antagonistic relationship for excess B and salinity. In other words, toxic effects on growth and yield were less severe for combined B toxicity and salinity than what would be expected if effects of the individual factors were additive. Similar antagonistic characteristics were found using data from three of the five studies reported in the literature. The mechanism of relationships between B and salinity in plants is not clear and several options are discussed. Prominent among the possible explanations are reduced uptake of B in the presence of Cl and reduced uptake of Cl in the presence of B.     

亚精胺浸种对渗透胁迫下白三叶子萌发及淀粉代谢的影响

以‘拉丁诺’白三叶为材料,用0、10％、15％、20％（W/V）即的聚乙二醇（PEG-6000）溶液模拟干旱条件,研究亚精胺fSpd）浸种对渗透胁迫下白三叶种子萌发和淀粉代谢的影响。结果表明,在PEG渗透胁迫下,白三叶种子的发芽率、发芽势、发芽指数、胚芽及胚根鲜重和胚根长度均显著（P〈0．05）降低,淀粉水解为糖类的速率减慢;与蒸馏水浸种相比,0．05mmol．L-1 Spd浸种处理显著（P〈0．05）提高了在渗透胁迫条件下种子的发芽率、发芽势、发芽指数、胚芽及胚根鲜重、干重和胚根长度,同时大幅提高了α-淀粉酶、β-淀粉酶及（α＋β）．淀粉酶总活性,降低了淀粉含量,增加了还原糖和葡萄糖含量。说明Spd浸种提高了白三叶种子在渗透胁迫下的萌发能力和幼苗生长的环境适应性,这可能与增强种子体内淀粉酶活性,加速淀粉水解为还原糖和葡萄糖,为种子萌发和幼苗早期生长及时提供充足能量有关。     

Substrate-dependent auxin production by Rhizobium phaseoli improves the growth and yield of Vigna radiata L. under salt stress conditions

Rhizobium phaseoli strains were isolated from the mung bean nodules, and, the most salt tolerant and high auxin producing rhizobial isolate N20 was evaluated in the presence and absence of L-tryptophan (L-TRP) for improving growth and yield of mung bean under saline conditions in a pot experiment. Mung bean seeds were inoculated with peat-based inoculum and NP fertilizers were applied at 30-60 kg ha-1, respectively. Results revealed that imposition of salinity reduced the growth and yield of mung bean. On the contrary, separate application of L-TRP and rhizobium appeared to mitigate the adverse effects of salt stress. However, their combined application produced more pronounced effects and increased the plant height (28.2%), number of nodules plant-1 (71.4%), plant biomass (61.2%), grain yield (65.3%) and grain nitrogen concentration (22.4%) compared with untreated control. The growth promotion effect might be due to higher auxin production in the rhizosphere and improved mineral uptake that reduced adverse effects of salinity. The results imply that supplementing rhizobium inoculation with L-TRP could be a useful approach for improving growth and yield of mung bean under salt stressed conditions.     

Influence of plant growth regulators on growth, morpho-physiological characters and yield of summer sesame (Sesamum indicum L. cv. Rama) under moisture stress

Field experiments were conducted with sesame (Sesamum indicum L. cv. Rama) for two years (1997 and 1998) to study the effect of three level of irrigation (F+C, B+C, B+F+C) and two growth regulators (CCC, 200 ppm CCC; 100 ppm and BX-112, 100 ppm; BX-112, 50 ppm) on growth (root and shoot length, average number of primary branches/plant), morpho-physiological growth parameters(LAI, LAD, CGR and NAR), yield attributing parameters(average number of capsule/plant, average number of seeds/capsule) and seed yield. Irrigation at B+F+C stage showed significant effect on these parameters. Among the growth regulators, CCC, 200 ppm showed remarkable results on these parameters and seed yield. Seed yield in CCC, 200 ppm treatment was more than 53% in comparison to water soaked seeds. The interaction between irrigation and PGR showed better seed yield and it was concluded that the growth regulator CCC might be utilized for enhancement of seed yield of summer sesame under field condition.     

光照和不同药剂浸种对龙葵种子发芽率的影响

为探索超富集植物龙葵种子的快速发芽方法,以滤纸为发芽基质,采用恒温培养箱及温室培养的方法,对龙葵种子进行不同浸种处理,探讨光照及不同浸种液对龙葵种子发芽的影响.结果表明: 光照条件是龙葵种子发芽的重要条件之一,光照条件下的发芽率约为无光照条件下发芽率的5倍(P<0.05);不同浸种液均能显著提高龙葵种子的发芽率,其中以双氧水的处理效果最好,发芽时间最短(P<0.05);浸种后不经清洗处理的龙葵种子发芽率约为浸种后再经清洗处理发芽率的2～3倍(P<0.05).     

Growth of bean and tomato plants as affected by root absorbed growth substances and atmospheric carbon dioxide

Summary Bean and tomato plants were grown in solution culture root media containing pre-determined concentrations of gibberellin A₃ (GA), 1-naphthaleneacetic acid (NAA), N⁶-benzyladenine (BA), (2-chloroethyl)trimethylammonium chloride (CCC), and at atmospheric levels of 300 and 1000 ppm of CO₂. Net assimilation rates (NAR), relative growth rates (RGR), leaf area ratios (LAR), root to top dry weight ratios (R/T) and changes in dry weight, size, and form of each organ were recorded.Gibberellin had no effect on RGR of either plant species but increased the NAR of tomatoes at 1000 ppm CO₂. Total dry weight was only slightly affected by GA but root growth and R/T were markedly depressed. CCC had no effect on NAR, but decreased RCR and LAR. Root growth of beans and R/T in both plants were promoted by CCC. NAR and RGR were strongly inhibited by BA and NAA. Inhibition of stem and leaf growth by CCC and NAA was greater than that for roots; thus, R/T ratios were increased. Root branching was promoted by NAA.High (1000 ppm), compared to the low (300 ppm), atmospheric levels of CO₂ generally promoted root growth and produced an increase in the R/T, both in the absence and presence of chemical treatment. The multiplicity of effects of the rootabsorbed chemical growth substances and CO₂ on growth and photosynthesis is discussed.Journal article No 3883 of the Michigan Agricultural Experiment Station.NATO Fellow, University of Pisa, Italy.