[Effects of p-hydroxybenzoic acid and phloroglucinol on mitochondria function and root growth in cotton (Gossypium hirsutum L.) seedling roots.] / å¯¹ç¾ŸåŸºè‹¯ç”²é ¸å’Œé—´è‹¯ä¸‰é šå¯¹æ£‰èŠ±å¹¼è‹—æ ¹ç³»çº¿ç²’ä½“åŠŸèƒ½å’Œæ ¹ç³»ç”Ÿé•¿çš„å½±å“.

With early-maturing cotton cultivar CCRI-50 widely grown in China as experimental material, water culture experiment was conducted to study the effects of p-hydroxybenzoic acid and phloroglucinol with different concentrations (0.8, 4.0, and 20.0 mmol·L-1) on generation rate of reactive oxygen, changes of antioxidant enzyme activities and mitochondria function of cotton roots. Results showed that p-hydroxybenzoic acid and phloroglucinol treatments inhibited the cotton root growth, reduced SOD, POD, CAT and H+-ATPase activities in root mitochondria, increased the generation rate of O2-· and H2O2 content. In addition, they also increased the opening of mitochondrial permeability transition pores (MPTP), decreased the membrane fluidity and cytochrome c/a (Cyt c/a). Difference of mitochondria function between p-hydroxybenzoic acid and phloroglucinol treatments was minor at concentration of 0.8 mmol·L-1, while the inhibition to root growth and mitochondria function under treatment of p-hydroxybenzoic acid at concentration of 4.0 and 20.0 mmol·L-1 was stronger than that of phloroglucinol. Above all, p-hydroxybenzoic acid and phloroglucinol inhibited antioxidant enzyme activity and mitochondrial function in cotton seedling roots, and the inhibition depended on dose of phenolic acids. The inhibition to root growth and mitochondria function between p-hydroxybenzoic acid and phloroglucinol treatment was different, and p-hydroxybenzoic acid had stronger inhibition than phloroglucinol at the concentration more than 4.0 mmol·L-1.

[Effects of brassinolide on leaf physiological characteristics and differential gene expression profiles of NaCl-stressed cotton].

This study analyzed the effects of brassinolide (BL) on Na⁺ accumulation, leaf physiological characteristics and differentially expressed genes (DEGs) of cotton leaves under NaCl stress. The results showed that NaCl stress increased the Na⁺, proline and MDA content in the leaves of Sumian 12 and Sumian 22, and changed the expression level of genes in cotton leaves. The application of BL counteracted the NaCl stress-induced growth inhibition in the two tested cotton cultivars. It reduced the accumulation of Na⁺, enhanced proline content, and resulted in a decrease in the MDA content of NaCl-stressed leaves, and the influence of BL on salt-stressed Sumian 12 plants was more pronounced than that on Sumian 22. The digital gene expression analysis in Sumian 12 indicated that BL application significantly influenced the gene expression in NaCl-stressed cotton leaves, the gene expression pattern as a result of the root applied BL on NaCl-stressed cotton treatment (BL+NaCl) was similar to the normal cotton plants (CK). Our results indicated that brassinolide alleviated NaCl stress on cotton through improving leaf physiological characteristics and gene expression, and resulted in an increase in biomass of NaCl-stressed cotton.

[Effects of nitrogen application rates on nitrogen uptake and utilization of direct-seeded cotton after wheat harvest].

An experiment was carried out to study the effects of different nitrogen application rates (0, 60, 120, 150, 180 and 240 kg N · hm⁻²) on the nitrogen uptake, utilization and distribution of short season cotton cultivar (CCRI-50) which was directly seeded after wheat harvest. Results showed that nitrogen application increased the nitrogen uptake of cotton at different growth stages, with the highest increment at the peak flowering-boll opening stage. Nitrogen application changed the percentages of nitrogen uptake among different growth stages. The percentages of nitrogen uptake decreased from seedling to peak flowering stage, but increased from peak flowering to boll maturing stage. In addition, nitrogen application reduced the decreasing speed of nitrogen concentration in middle and upper fruiting branches at later growth stages. Direct-seeded cotton had nitrogen and biomass accumulation in the lower and middle reproductive branches. With the nitrogen application of 150-180 kg · hm⁻², the lint yield, NARE (nitrogen apparent recovery efficiency) and the economic coefficient of biomass and nitrogen were relatively higher, and the eigenvalues of dynamic model of nitrogen content and nitrogen accumulation were relatively coordinate. Excessively high nitrogen application (over 180 kg N · hm⁻²) decreased biomass and nitrogen amount of reproductive organ in lower and middle branches, narrow rise of yield, and lower nitrogen use efficiency. However, excessively low nitrogen application (lower than 150 kg N · hm⁻²) also resulted in lower economic coefficient of biomass and nitrogen and yield. These results suggested the optimum nitrogen application rate 150-180 kg N · hm⁻² for direct-seeded cotton after wheat harvest in lower reaches of Yangtze River.

[Effects of nitrogen application rate on potassium uptake and utilization of direct-seeded cotton after wheat harvest]. / æ–½æ°®é‡å¯¹éº¦åŽç›´æ’­æ£‰é’¾ç´ å¸æ”¶åˆ©ç”¨çš„å½±å“.

By using cotton cultivar CCRI-50 as material, field experiments were conducted in the summer seasons of 2013 and 2014 at the experimental station of Jiangsu Academy of Agricultural Sciences (Nanjing, China) to study the effects of different nitrogen application rates (0, 60, 120, 150, 180 and 240 kg N·hm-2) on the potassium uptake and utilization of the cotton plant that was direct-seeded after wheat harvest. Data suggested that the elevated nitrogen application rates increased the cotton potassium uptake of all growth stages, and the largest increment was observed at the peak flowering-boll opening stage. Nitrogen application also changed the uptake percentage of potassium uptake of each stage, i.e., the percentage of potassium uptake decreased in the stage from seedling to peak flowering, while increased in the stage from peak flowering to boll maturing. In addition, the elevated nitrogen applications reduced the decreasing rate of nitrogen concentration in upper fruiting branches, but promoted the decreasing rate in middle and low fruiting branches at later growth stages. As the nitrogen application rate increased, the marginal effect of potassium uptake (promoted amount of potassium uptake due to 1 kg increase of N application) increased first and then decreased, and the lint production efficiency of potassium descended steadily. In cotton plants that were direct-seeded after wheat harvest, potassium and biomass were mainly accumulated in the lower and middle fruiting branches. At the 150 and 180 kg N·hm-2 application levels, much more potassium was allocated to the reproductive organs and the characters and the eigenvalues of simulated curves of potassium concentration and total potassium accumulation were more optimized than those at the higher or the lower N application levels. At the high nitrogen application (more than 180 kg N·hm-2) level, the marginal effect of potassium uptake and lint production efficiency decreased, and at the lower nitrogen application (less than 150 kg N·hm-2) level, lint yield was lower due to the decrease of economic coefficient of biomass and potassium in the middle and low fruiting branches.

[Molecular cloning and expression analysis of a SUPERMAN-like zinc finger protein gene in upland cotton].

The zinc finger proteins belong to the largest family of regulatory transcription factors, which play an important role in growth and development in animal and plant systems. SUPERMAN-like zinc finger protein gene has only one "finger like" motif. A pair of degenerate primers was designed according to the conserved regions, and 3 kinds of EST of this family were isolated from cotton through RT-PCR. The full length of one SUPERMAN-like zinc finger protein also has been acquired. The entire coding region is 744 bp and encodes a polypeptide of 248 amino acids with 40% homology to RBE protein of Arabidopsis deposited in the GenBank. This gene was designated as GZFP. It has the conserved zinc finger domain and the leucine rich region at the carboxyl terminus but no intron in the coding region. GZFP also has the plant nuclear localization signal. GZFP shows a more expression pattern in floral buds, ovaries, petals and roots than in phloem, xylem, fibers, leaves and seeds of cotton by RT-PCR, although it has a very low detection level and there is not any homologous ESTs found in the GenBank. Analysis of the 5' flanking sequence shows there are several regulatory elements responsible for pollen and root expression, four core sites required for binding of Dof proteins and four light-regulated elements.

[Expression of Vitreoscilla hemoglobin and nitrilase in the yeast Pichia pastoris].

The expression of the vgb gene in vivo could improve the fermentation density and then contribute the extracellular secretion of the product of bxn gene. Constructed the recombination plasmid pPIC9K-vgbbxn and transformed into Pichia pastoris GS115. The results of PCR and SDS-PAGE indicate that the vgb gene and bxn gene had integrated into the genome of Pichia pastoris GS115 and expressed in efficient level. Also, the protein activity of their products had been verified respectively. Shake flask fermentation experiments showed that the presence of VHb in yeast Pichia pastoris efficiently enhanced cell growth and secretive expression of bxn gene under hypoxic habitats.