After ring different dence," while g a dynamic ntries and the d from 1990 to 2003. The empirical results find supportive evidence of a contagion effect. By analyzing the correlation-coefficient series, this paper the Asian crisis. The first phase shows an increase in correlation (contagion) and the second phase shows continued high correlation (herding). Statistical ll as in the variance of the correlation coefficients, casting some doubt on the benefit of international portfolio
The objective of this study was to determine the effects of different light-emitting diode (LED) light sources on the growth of upland cotton (Gossypium hirsutum L.) plantlets. Shoot bud apex cuttings of upland cotton (1.0 cm) were transplanted on Murashige and Skoog (MS) basal medium supplemented with 0.1 mg/l 6-benzyladenine (BA) and 0.5 mg/l naphthalene acetic acid (NAA) and cultured in vitro for 45 days. They were exposed to 50 lmol m -2 s -1 photosynthetic photon flux (PPF) and a 12-h photoperiod under six different lights: fluorescent lamp (CON), monochromatic blue LED (B), three blue and red LED mixtures (B:R = 3:1, 1:1, 1:3) and monochromatic red LED (R). The effects of the six light sources on growth and morphogenesis of upland cotton plantlets grown in vitro were investigated. Fresh weight, dry weight, stem length and second internode length were greatest in plantlets cultured under the B:R = 1:1 blue and red LED light, followed by blue LED light, and they were lowest in plantlets cultured under a fluorescent lamp. Chlorophyll content, leaf thickness, palisade tissue length, leaf and stomata area were highest in plantlets cultured under blue LED light. Root activity, sucrose, starch and soluble sugar contents were highest in plantlets cultured under red LED light. Our results showed that larger, healthier plantlets and a greater biomass of upland cotton were produced in the presence of red LED supplemented with a quantity of blue LED light. Blue and red LED (B:R = 1:1) was the most suitable light for the growth of upland cotton plantlets in vitro, and it may be used as alternative light source for an upland cotton culture system.
To date, little is known about the effects of different light sources on the growth and quality of non-heading Chinese cabbage (Brassica campestrisL.). The objective of present study was to evaluate the effects of light-emitting diodes (LEDs) light sources (blue, blue plus red, red), fluorescent lamps and sunlight on growth and vitamin C, soluble protein, sucrose, soluble sugar, starch and pigment concentrations in non-heading Chinese cabbage seedlings. The dry mass of shoots and the fresh and dry masses of roots were highest in seedlings grown under red LEDs with weak lights. The fresh mass of roots and starch concentration were highest under red LEDs despite of the altered photosynthetic photo flux density (PPFD) levels. The concentrations of chlorophylls and vitamin C were greatest under blue LEDs with altered PPFD levels. The numbers of flower buds and open flowers were highest under red LEDs and blue plus red LEDs and were higher under LEDs than fluorescent lamps. The duration of flowering was highest under red LEDs and blue plus red LEDs. The present results demonstrate that LED light sources are more effective than fluorescent lamps for vegetative and reproductive growth of non-heading Chinese cabbage. Moreover, blue LEDs benefit vegetative growth, while red LEDs and blue plus red LEDs support reproductive growth in non-heading Chinese cabbage. In the artificial cultivation and subsequent transplanting of the life cycle of plants, the light source can be selected to meet the requirements of different growth stages of plants and be used to promote the subsequent process in the industrial production of non-heading Chinese cabbage.
Abstract:The plant hormone auxin plays pivotal roles in many aspects of plant growth and development. The auxin/indole-3-acetic acid (Aux/IAA) gene family encodes short-lived nuclear proteins acting on auxin perception and signaling, but the evolutionary history of this gene family remains to be elucidated. In this study, the Aux/IAA gene family in 17 plant species covering all major lineages of plants is identified and analyzed by using multiple bioinformatics methods. A total of 434 Aux/IAA genes was found among these plant species, and the gene copy number ranges from three (Physcomitrella patens) to 63 (Glycine max). The phylogenetic analysis shows that the canonical Aux/IAA proteins can be generally divided into five major clades, and the origin of Aux/IAA proteins could be traced back to the common ancestor of land plants and green algae. Many truncated Aux/IAA proteins were found, and some of these truncated Aux/IAA proteins may be generated from the C-terminal truncation of auxin response factor (ARF) proteins. Our results indicate that tandem and segmental duplications play dominant roles for the expansion of the Aux/IAA gene family mainly under purifying selection. The putative nuclear localization signals (NLSs) in Aux/IAA proteins are conservative, and two kinds of new primordial bipartite NLSs in P. patens and Selaginella moellendorffii were discovered. Our findings not only give insights into the origin and expansion of the Aux/IAA gene family, but also provide a basis for understanding their functions during the course of evolution.
Grain weight, an essential yield component, is under strong genetic control and markedly influenced by the environment. Here, by genome-wide association analysis with a panel of 94 elite common wheat varieties, 37 loci were found significantly associated with thousand-grain weight (TGW) in one or more environments differing in water and fertiliser levels. Five loci were stably associated with TGW under all 12 environments examined. Their elite alleles had positive effects on TGW. Four, two, three, and two loci were consistently associated with TGW in the irrigated and fertilised (IF), rainfed (RF), reduced nitrogen (RN), and reduced phosphorus (RP) environments. The elite alleles of the IF-specific loci enhanced TGW under well-resourced conditions, whereas those of the RF-, RN-, or RP-specific loci conferred tolerance to the TGW decrease when irrigation, nitrogen, or phosphorus were reduced. Moreover, the elite alleles of the environment-independent and -specific loci often acted additively to enhance TGW. Four additional loci were found associated with TGW in specific locations, one of which was shown to contribute to the TGW difference between two experimental sites. Further analysis of 14 associated loci revealed that nine affected both grain length and width, whereas the remaining loci influenced either grain length or width, indicating that these loci control grain weight by regulating kernel size. Finally, the elite allele of Xpsp3152 frequently co-segregated with the larger grain haplotype of TaGW2-6A, suggesting probable genetic and functional linkages between Xpsp3152 and GW2 that are important for grain weight control in cereal plants. Our study provides new knowledge on TGW control in elite common wheat lines, which may aid the improvement of wheat grain weight trait in further research.
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