In vertebrates, it is a remarkable feature that the internal organs and nervous system are asymmetrically distributed along the left-right axis. As same as the anterior-posterior and dorsal-ventral axes, left-right asymmetry is established progressively during the early developmental stage. Left-right asymmetry development is induced by the conserved Nodal-Pitx2 signal. The concrete process includes the breaking of the symmetry, the establishment and maintenance of asymmetric signal, and the position of the eventual organ. The recent progress in left-right asymmetry development was reviewed. And recent researches have explored the establishment of left-right axis using model organisms such as mouse, zebrafish, Xenopus, etc., which help us deeply understand this developmental process.

Antifreeze proteins (AFPs), a class of antifreeze substances, were initially found to bind to ice crystals in vivo, thereby contributing to inhibition of the growth of ice crystals that enabled polar fish to survive at the temperatures below freezing point. As a potential cryoprotectant, AFPs had been used for cryopreservation of germ cells, embryos and other biological samples. In this review, the application of AFPs to the cryopreservation of livestock tissues and cells in recent 10 years was summarized. The characteristics and principles of frost protection of AFPs under different biological models were discussed, and the possible influencing factors of AFPs in the cryopreservation of biological samples were analyzed. The protective effects of AFPs on sperm cryopreservation and its action mechanism were summarized, and the theoretical references were provided for the application of AFPs in cryopreservation of animal sperm. The non-toxicity and peculiar biological characteristics of AFPs in cryopreservation provided a new solution for livestock semen cryopreservation. Therefore, AFPs have a broad prospect in cryopreservation of sperm.

The effects of tea flower saponin, which was extracted and purified by macroporous resin and preparative liquid chromatography, on the proliferation and traits of human ovarian cancer stem like cells (OCSLCs) and its mechanism were studied. The stem cell marker aldehyde dehydrogenase (ALDH) activity, cell vitality, colony formation capacity, tumor sphere formation capacity and the expression of stemness-related proteins were measured to investigate the effects of tea flower saponin on OCSLCs of A2780/CP70 cells obtained by serum-free suspension culture. Western blot assay was used to investigate the effects of tea flower saponin on Wnt/β-catenin signaling pathway proteins. The results showed that tea flower saponin could decrease the proliferation of OCSLCs by suppressing their cell activity and colony formation ability. Tea flower saponin inhibited the formation of tumor sphere and reduced cell self-renewal ability. The ALDH^＋ cell proportion and expressions of Oct-4 and Nanog proteins were decreased in OCSLCs treated with tea flower saponin. In addition, tea flower saponin treatment could down-regulate the expression of P-AKT, P-GSK-3β, β-catenin, c-Myc and up-regulate the expression of P-β-catenin to inhibit the Wnt/β-catenin signaling pathway. These results indicate that suppression of the Wnt/β-catenin signaling pathway might be one of the mechanisms by which tea flower saponin inhibits the proliferation of OCSLCs and cancer stem cell traits.

In order to further study the functions of class Ⅲ peroxidase (PRX) family genes in Brassica rapa (BrPRX), the BrPRX was identified by genome-wide analysis, and its bioinformatics analysis was carried out. The results showed that there were a total of 121 BrPRX members, contained 0-9 introns, exhibited unequal distribution on chromosomes, and multiple pairs of BrPRX genes were distributed on chromosomes with tandem duplication. Phylogenetic analysis of PRX family genes from Arabidopsis thaliana and B. rapa suggested that these members could be divided into five groups. Synteny and K_a/K_s analyses demonstrated that B. rapa had a high homology with A. thaliana, and most of BrPRX family gene had undergone strong purifying selection in the evolution. The analysis of cis-acting regulatory elements of BrPRX family genes showed that they played important roles in hormone response regulation, light response and resistance to adversity. In addition, transcriptome data analysis showed that the BrPRX genes had tissue expression specificity, and some of them were down-regulated in the male sterility materials. These results lay a foundation for the further study of PRX genes’ function in B. rapa.

In order to examine the genetic background of Micropterus salmoides, eleven microsatellite loci were used to study the genetic diversity and structure of the introduced subspecies (California M. salmoides), selected subspecies from Taiwan Province (Taiwan-California M. salmoides) and cultured species (Youlu No. 1) in mainland. The results showed that both the number of alleles and effective alleles was higher in California M. salmoides than in Taiwan-California M. salmoides and Youlu No. 1. The observed heterozygosity and expected heterozygosity at five loci were significantly higher in California population than in Taiwan-California and Youlu No. 1 populations, which were similar. According to the polymorphic information content, eleven loci in the California population were at high polymorphic levels. Six loci and four loci were at highly polymorphic levels for Youlu No. 1 and Taiwan-California populations, respectively. In the genetic equilibrium test, it was found that there were more loci deviating from Hardy-Weinberg equilibrium in Taiwan-California population, and there were three linkage pairs in California population (P＜0.05). For the two-phased model of mutation (TPM), both WILCOXON and sign tests showed that California population was in a status of mutation-drift disequilibrium. For population structure, it was found by analysis of molecular variance (AMOVA) that 15.57% of the genetic variation came from among populations, 25.05% from within populations, and 59.38% from among individuals (P＜0.01). The genetic distance between California population and Youlu No. 1 population was the largest, followed by that between California population and Taiwan-California population. When the K was two, there were significant differences in genetic structures between California population and other two populations. Through individual population identification, California population had the lowest rate of misjudgment, followed by Youlu No. 1 and Taiwan-California populations. When the accuracy was 85.00%, the probabilities of correct discrimination of California, Youlu No. 1 and Taiwan-California populations were 67.70%, 53.30% and 20.00%, respectively. According to the analysis of genetic diversity, genetic distance and equilibrium test, it was found that the original species of California had high polymorphism, and the genetic distance was bigger than that of the other two populations, and there might be genetic bottleneck. It is suggested that the species of M. salmoides introduced from the United States should be expanded and cultivated systematically.

In order to determine the effect of newly developed biodegradable liquid mulch (BDLM) on soil temperature, seed germination, and seedling growth of upland cotton, an experiment was carried out at the Agricultural Experiment Station of Zhejiang University in 2018 and 2019. The results showed that BDLM exhibited significant improvement with respect to soil temperature, cotton seed germination rate, stem and leaf biomass (P＜0.05) compared with bare soils. In comparison with plastic mulch, BDLM had no significant effects on soil temperature and cotton seed germination rate. In order to evaluate the effect of BDLM residues on cotton seedling growth under different soil types, a pot trial was carried out in a growth chamber. The results revealed that BDLM residues had significant effect on cotton seed germination rate. The interaction of soil types and BDLM residues had significant effects on chlorophyll content, leaf area index (LAI) and soil moisture content (P＜0.05). The highest chlorophyll content was observed from loam soils with BDLM residues, and the highest leaf area index was observed from clay soils with plastic residues, and lowest moisture content was observed from traditional loam soils. In conclusion, BDLM has positive effect on cotton growth, however further researches should be proposed during cotton harvesting stage.

In order to study the genetic relationship and genetic mechanism of ‘Yongtai’ and related nine bayberry (Myrica rubra) accessions, the methods of genomic re-sequencing and phylogenetic tree construction of core single nucleotide polymorphism (SNP), etc. were used, and also 4 025 core SNP markers were developed for further genetic and breeding research. The results calculated by genetic similarity (GS) showed that the GS between ‘Yongtai’ and ‘Yingsi’ was 0.997 83. Moreover, ten bayberry accessions were divided into two groups by phylogenetic tree construction analysis of SNP. ‘Heijing’, ‘Dong’aozaomei’, ‘Wuzi’, ‘Biqi’, ‘Muye’ were grouped together, and ‘Zaodamei’, ‘Zaojia’, ‘Ruansi’, ‘Yongtai’ and ‘Yingsi’ were grouped together, where ‘Yingsi’ and ‘Yongtai’ were gathered into a branch. At the same time, there were significant differences between ‘Yongtai’ and its parents in leaf size, leaf margin, leaf vein and fruit flavor. Through comparison and annotation of ‘Yongtai’ and the reference genome, a total of 4 660 differential genes were obtained. In conclusion, the significant morphological variation in leaves and fruits of ‘Yongtai’ may be attributed to the transition and transversion of SNP and the mutation of nucleotide sequence. So ‘Yongtai’ not only has the basic traits of its parent ‘Yingsi’, but also has its typically morphological traits as large leaves and large fruits.

In order to investigate the growth and aluminum (Al) absorption responses of Hydrangea macrophylla under combined stress of simulated acid rain and Al, we studied biomass accumulation, photosynthetic pigment contents, chlorophyll fluorescence characteristics, and Al accumulation and distribution of ‘Mama Blue’ under different treatments [acid rain (pH 5.0 and 3.0), aluminum (Al^3＋ 1 and 2 g/kg) and their combinations] by pot experiments. The results showed that there were no significant effects on chlorophyll contents and photosystemⅡ (PSⅡ) reaction center under single acid rain treatment, and the biomass of root, stem, leaf and total biomass accumulation significantly increased under pH 5.0 treatment. Aluminum (2 g/kg) alone significantly decreased the total biomass, chlorophyll (a/b) value, photochemical quenching coefficient (q_p) and electron transport rate (ETR), but the non-photochemical quenching coefficient (NPQ) was improved markedly. The low pH and high concentration of Al destroyed the PSⅡ reaction center, reduced the photosynthetic pigment contents, affected its composition, and inhibited the growth of the plant. In addition, acid rain, Al stress and the compound treatment significantly increased the accumulation of leaves and total Al in the plants. Compared with Al stress alone, the total aluminum content under the compound pollution was higher at the same Al concentration. The accumulation of aluminum in different parts of the plant was as follows: root＞stem＞leaf. The interaction of acid rain and aluminum had significant impacts on NPQ, leaf and total biomass, and aluminum contents in various parts of the plant. In conclusion, H. macrophylla has strong acid resistance, and aluminum pollution affects them more than acid rain stress; acid rain promotes the absorption of aluminum, and the compound pollution of high aluminum and strong acid is disadvantageous to the growth of H. macrophylla.

Macroalgal biochars were produced from Sargassum fusiforme, Sargassum thunbergii, Sargassum vachellianum, Grateloupia turuturu, Chondria crassicaulis and Ulva pertusa at different pyrolysis temperatures (200, 300, 400, 500 and 600 ℃) under limited-oxygen conditions. The effects of pyrolysis temperature on the yield, heavy metal (Fe, Mn, Zn, Cu, As, Cr, Cd, Pb and Hg) contents and their relative enrichment factors of different macroalgal biochars were investigated. The results indicated that the yield of macroalgal biochar decreased with the increase of pyrolysis temperature. The contents of Fe, Zn, Mn, Cu, Cr and Pb in macroalgal biochars were significantly higher than those in their respective biomass. The As content in macroalgal biochars decreased first and subsequently increased with the increase of pyrolysis temperature, and the As content was not higher than that of raw biomass. The change trend of Cd content with the increase of pyrolysis temperature was related to macroalgae biomass. Hg wasn’t detected in the biochars. The contents of Zn, Cu, Cr, Pb and Hg in macroalgal biochars were all better than the basic quality grade stipulated by the European Biochar Foundation, but the contents of Cd and As in the partial biochars exceeded the threshold. In general, pyrolysis may promote the volatile migration of heavy metals in the macroalgal biochar. Furthermore, the correlation analysis showed that the heavy metal contents in the macroalgal biochars were critically dependent on the biomass and pyrolysis temperature. Cluster analysis demonstrated that the prepared biochars from the special macroalgae biomass could be approximately classified into the same cluster, which effectively reflected the differences in the characteristics of heavy metals in different macroalgal biochars. The above results can provide valuable information for guiding the production and application of macroalgal biochar, which improving the utilization of macroalgae.

This study aimed to understand the passivation effects and mechanisms of bio-organic fertilizer made from Chinese traditional herb residues (BOFCTHR) on heavy metals in farmland soils. The soils with three levels of Cd-contamination were collected from Longli County (high pollution), Wanshan District, Tongren City (medium pollution), and Danzhai County (low pollution) in Guizhou Province. A soil incubation experiment was conducted to study the effect of BOFCTHR on soil organic matter, pH, cation exchange capacity (CEC), the morphological transformation of Cd and Hg, immobilization efficiency (IE) and mobility index (MI) under the addition of 0 (CK), 1.5%, 3.0% and 6.0% BOFCTHR, respectively; and the correlation between the physiochemical properties of soils and the forms of heavy metals was analyzed. The results showed that the application of BOFCTHR increased significantly soil organic matter content, pH, and CEC in a dose-dependent manner. The application of BOFCTHR decreased exchangeable and carbonate-bound form contents of Cd and Hg, increased organic-bound and residual form contents of Cd and Hg; and the reduce amplitude of exchangeable and carbonate-bound form contents of Cd and Hg, and the increment amplitude of organic-bound and residual form contents of Cd and Hg followed the order: 6.0% BOFCTHR＞3.0% BOFCTHR＞1.5% BOFCTHR. The application of BOFCTHR decreased MI of Cd and Hg, and increased IE of Cd and Hg; and the reduce amplitude of MI of Cd and Hg, and the increment amplitude of IE of Cd and Hg followed the order: 6.0% BOFCTHR＞3.0% BOFCTHR＞1.5% BOFCTHR. The correlation analysis showed that soil organic matter content, pH, and CEC were significant negative correlation with exchangeable form content of Cd and Hg (P＜0.05), and significant or extremely significant positive correlation with organic-bound form content of Cd (P＜0.05 or P＜0.01); soil organic matter content and CEC were significant positive correlation with organic-bound form content of Hg (P＜0.05). It is concluded that BOFCTHR may affect the passivation effect of heavy metals in the soil by changing the physiochemical properties.

This study focused on exploring the optimal fertilization strategies for cotton planted in coastal severe saline-alkali soils based on irrigation with saline water in winter. A four-year positional experiment was conducted on cotton based on irrigating saline water in lower plain of Hebei, including fertilizer types (controlled-release/loss-control fertilizer and traditional fertilizer), fertilization modes (application once as base fertilizer, application twice as base and topdressing fertilizer, respectively) and fertilization rates (high and low amount). The results showed that the salinity of 0-20 cm soil depth was reduced to less than 2.0 g/kg during the sowing seasons in spring as a result of irrigating saline water, which ensured germination and emergence of cotton seeds. In terms of fertilizer type, the first choice for planting cotton was the loss-control fertilizer that containing N-P-K and attapulgite in the severe saline-alkali area, and applied once as base fertilizer. Whether the traditional fertilizer mix was used, the potassium sulfate fertilizer was necessary besides urea and superphosphate, and all fertilizers should be applied once as base fertilizer before sowing. Given equal amount of nitrogen, urea applications once as base fertilizer had a significant increase in cotton yield, compared with twice application as base and topdressing fertilizer. Moreover, the latter could result in risks of soil inorganic-N accumulation and saline content increase after harvest. Excessive fertilizer application inhibited cotton seedling and plant growth during the early growing stage, and then influenced cotton yield at last. So the fertilization strategies for cotton planted in coastal severe saline-alkali area in North China were as follows: during the winter freezing period before sowing, local underground salt water was extracted for irrigation, and the irrigation amount was 100-180 mm; the reasonable amount of fertilizer applied once before sowing in spring was 169 kg/hm² N, 65 kg/hm² P₂O₅, and 78 kg/hm² K₂O; and the fertilizer dosage form should be preferred to loss-control fertilizer. Under the optimal fertilization strategies, the seed cotton yield in the severe saline-alkali soils could reach to 3.0-3.2 t/hm². The above results provide theoretical basis and technical support for the development and utilization of saline-alkali soils and its underground salt water resources, as well as fertilizer saving, yield increasing, and the green and efficient planting of salt-tolerant cotton.

In order to investigate the effects of structural and working parameters on the working resistance and subsidence depth of boat-type tractor in paddy field, simplified prototypes of boat-type tractors with testing system were developed. Ground ratio pressure, working speed, curvature radius of board, ground contact angle and depth of surface water of paddy soil were taken as factors, and working resistance and subsidence depth were taken as evaluation indexes. The experiments were conducted through the paddy soil platform which was filled with filtered silt loam. Results showed that all the factors had significant effects on the two evaluation indexes. The working resistance and subsidence depth increased monotonously with the increase of ground ratio pressure within 250-350 kg/m². However, when the ground ratio pressure was beyond 300 kg/m², the increase of two evaluation indexes was much slower. When working speed, curvature radius of board and ground contact angle were within 0.2-1.0 m/s, 300-500 mm and 25.0°-35.0°, respectively, the working resistance and subsidence depth increased after a slight decrease on the whole. The working resistance and subsidence depth reached the minimum values at the working speed of 0.6 and 0.8 m/s, respectively; and subsidence depth and working resistance reached the minimum values with ground contact angle of 27.5° and 30.0°, respectively. When the depth of surface water of paddy soil increased within 10-50 mm, the subsidence depth decreased monotonously, while the working resistance increased after a slight decrease on the whole. The working resistance reached the minimum value with the depth of surface water of 20 mm. In conclusion, the optimum working and structural parameters for boat-type tractors in paddy field are 0.6-0.8 m/s for working speed, 350-450 mm for curvature radius of board, 27.5°-30.0° for ground contact angle, and 20-40 mm for depth of surface water. The result can provide references for the design and operation of boat-type tractor in paddy field.