[Effects of regulation measure on soil and microbial biomass of moderately degraded alpine meadow in Qilian Mountain, China]. / 调控措施对祁连山中度退化高寒草甸土壤的影响.

We examined the effects of different regulation measures (spring rest grazing, spring rest grazing-cutting turf, spring rest grazing-cutting turf-fertilization, spring rest grazing-cutting turf-sowing, spring rest grazing-cutting turf-fertilization-sowing) on vegetation, soil physical and chemical properties, and soil microbial biomass in mode-rately degraded alpine meadow in Qilian Mountain. The results showed that all the regulation measures significantly increased plant coverage and aboveground and underground biomass of degraded alpine meadows. Plant species richness increased significantly under the two measures of spring rest grazing-cutting turf-fertilization and spring rest grazing-cutting turf-fertilization-sowing. The dominant species of spring rest grazing-cutting turf-sowing and spring rest grazing-cutting turf-fertilization-sowing was Poa pratensis cv. Qinghai. Soil pH and bulk density in moderately degraded alpine meadow (control) were significantly higher than those of all regulation measures. Soil water content, soil organic carbon, total nitrogen and total potassium, carbon-nitrogen ratio and nitrogen-phosphorus ratio of spring rest grazing-cutting turf-fertilization-sowing measures were the highest, which were 21.3%, 22.30 g·kg-1, 2.77 g·kg-1, 19.93 g·kg-1, 8.3 and 3.5, respectively. Soil microbial biomass nitrogen and phosphorus (104.98 and 40.74 mg·kg-1) of degraded meadows under spring rest grazing-cutting turf-fertilization-sowing measures were significantly higher than those of other measures, while soil microbial biomass carbon (240.72 mg·kg-1) of degraded meadows under spring rest grazing-cutting turf-fertilization measures was significantly higher than that of other measures. The results of radar map showed that the regulation measures affected the characteristics of degra-ded meadow vegetation (aboveground and underground biomass), soil physical and chemical properties (water content, organic carbon, total nitrogen, total phosphorus, and total potassium) and soil microbial biomass (carbon, nitrogen and phosphorus). Spring rest grazing-cutting turf-fertilization-sowing measures had the best performance in restoraing degraded meadows in the study area.

The characteristics of soil fungal community in degraded alpine meadow in the Three Rivers Source Region, China.

To clarify the variation of species composition, diversity, and functional structure of soil fungi community along alpine meadow degradation,we examined the characteristics and controlling factors of soil fungal communities in non-degraded, lightly degraded, moderately degraded, severely degraded and extremely degraded (black soil beach) alpine meadows at the Three Rivers Source Region, based on the high-throughput gene sequencing and FUNGuild functional prediction. The results showed that the dominant phyla in alpine meadow soil were Ascomycota, Basidiomycetes, and Mortierellomycota. Species composition of soil fungal community varied greatly in alpine meadow under different levels of degradation. The abundance of Cladosporium flabelliforme, Entoloma sodale, Hygrocybe conica, Inocybe sp. and Trichocladium opacum increased, while that of Gibberella tricincta and Dactylonectria macrodidyma decreased following grassland degradation. The meadow under severe degradation had higher soil fungal Chao1 index, while that under light degradation had lower Shannon index and Simpson index. The abundance of pathologic, symbiotic, and saprophytic types of fungi varied among different alpine meadows. Along with the grassland degradation, the abundance of soil symbiotic fungi decreased, while that of pathological fungi increased. The soil fungal community and functional compositions changed obviously with degradation in the alpine meadow. Plant aboveground biomass, soil water content, pH, total organic carbon, total nitrogen, ammonium nitrogen, available phosphate, total potassium and AN/AP (ratio of available nitrogen and available phosphorus) were the main driving factors for the variations in soil fungal community structure.

[Effects of enclosing on soil microbial community diversity and soil stoichiometric characteristics in a degraded alpine meadow]. / å›´å°å¯¹é€€åŒ–é«˜å¯’è‰ç”¸åœŸå£¤å¾®ç”Ÿç‰©ç¾¤è½å¤šæ ·æ€§åŠåœŸå£¤åŒ–å­¦è®¡é‡ç‰¹å¾çš„å½±å“.

Enclosing is an effective rehabilitation measure for degraded pastures that mimics natural recovery of vegetation. To examine the interaction between biotic and abiotic in lightly degraded and enclosing grasslands is helpful for a clear understanding of the structure and function of grassland ecosystem. In this study, soil microbial community and soil stoichiometric characteristics in lightly degraded and 10-year enclosing alpine meadows were studied by high-throughput sequencing and Biolog-Eco methods. The results showed that compared with lightly degraded grassland, the concentration of soil NH4+-N in the enclosing grassland increased significantly, while total K (TK) dramatically decreased. There was no obvious variation in soil total organic carbon (TOC), total N (TN), total P (TP), NO3--N, available P (AP), available K (AK), microbial biomass C (MBC) and microbial biomass N (MBN). The soil microbial biomass C/N was significantly enhanced. The carbon metabolic capabilities of soil microbes in different soil layers of alpine mea-dow were obviously increased with the prolonged incubation time, but there was no significant difference between lightly degraded and enclosed meadows. The OTUs of soil bacteria was significantly higher than that of fungi in alpine meadow. The microbial similarity between lightly degraded and fencing grasslands was 27.0%-32.7%. Enclosing significantly increased the fungal relative richness of Ascomycota, Zygomycetes and Chytridiomycota, while simultaneously decreased the rela-tive abundance of Basidiomycetes. Compared with lightly degraded meadow, the bacterial relative richness of Acidobacteria significantly decreased in enclosing meadow. The community composition of soil fungi and bacteria greatly varied among different soil layers. There was significant difference of fungal community composition in the upper soils between lightly degraded and enclosed grassland. The soil bacterial community diversity was greatly affected by soil TN and AK, while the fungal community diversity was significantly affected by plant aboveground biomass. Soil AK produced great influence on soil microbial carbon source utilization capacity. Generally, long-term grazing exclosure had no significant effects on soil nutrients and soil microbial community diversity of lightly degraded grassland and thus would waste the pasture resources, whereas appropriate grazing could maintain the sustainable utilization of grassland.

Effect of Over-nutrition in Postnatal Life on Growth of Female SD Rats / 中山大学学报(医学科学版)

@#【Objective】 To guide the nutritional intervention of children in the clinical practice ，by exploring the effect of over-nutrition in postnatal life on growth of the female SD rats.【Methods】We established the rat model of intra? uterine growth retardation（IUGR）through diet restriction in pregnant rats and selected female newborn rats that met the criteria as the experimental group（group I）. Group I was randomly divided into control group（group IC）and small group（group IS）. Fifty-eight female newborn rats with normal diet in pregnant period（group C）were also divided into control group（group CC）and small group（group CS）. After 21-days-lactation，group IC and group CC were randomly subdivided into 4 rats per cage，and then fed with normal diet，while group IS and group CS were fed with high fat diet. We measured the body weight and the body length of each rat every week. Serum fasting insulin，fasting blood glucose，IGF-1，IGF- BP3 levels，and rat insulin sensitivity index（ISI）were measured at different growth and development stages.【Results】 The body weight and body length of group IS were higher than those of group IC（P<0.05）；the same was true for group CS and group CC. In the different growth and development stages，the FINS，FBG，IGF- 1 and IGF- BP3 of group IS were higher than those of group IC（P < 0.05），the ISI was lower than that of group IC（P < 0.05）. Besides，the FINS，FBG of group CS were higher than those of group CC and the ISI of group CS was lower than that of group CC in the 75 days after birth（P < 0.05）.【Conclusions】We found that those small for gestational age infants can be added nutrition appropriately for rapid catch-up，but it is necessary to evaluate the growth index closely and adjust the nutrition on time. Children with normal intrauterine development also need to prevent over-nutrition.

Effects of Early Life Nutritional Status on Weight Catch-up Growth，Puberty Initiation and Obesity in Female Rats with Intrauterine Growth Retardation / 中山大学学报(医学科学版)

@#【Objective】To investigate the effects of different nutritional status in early life on weight catch-up，puberty initiation and obesity in rats with intrauterine growth retardation（IUGR）.【Methods】IUGR model of newborn rats was established by limiting diet during pregnancy in SPF rats. Female newborn rats were used in the experiment. IUGR rats were divided into two groups：small litter IUGR group（SL-IUGR）and common feeding IUGR group（CF-IUGR）. Rats of normal birth weight served as normal control group（NC）. The SL-IUGR group was used to simulate overfeeding in lactation period. After weaning，the rats in the three groups were fed with basic diet. The weights were measured at postnatal 1，7，14，21，35，42 and 75 days. The time of vaginal orifice opening（VO）was recorded. The levels of estradiol（E2），luteinizing hormone（LH）and follicle estrogen（FSH）were examined on the 21 d and the 35 d.【Results】The birth weight of IUGR rats was（4.92±0.18）g，which was significantly lower than that in the control group（6.00±0.29 g，P < 0.001）. IUGR rats showed weight growth catch- up on the 14th day. The body weight of SL- IUGR group was higher than that of control group from 14 to 75 d. The body weight of CF-IUGR group lagged behind that of control group from 1 to 75 d，the difference was statistically significant（P < 0.05）. The vaginal opening time of female IUGR rats in SL- IUGR group was （29.88 ± 1.81）d，which was significantly earlier than that of CF- IUGR group（32.03 ± 2.11）days（P = 0.044）. There was a correlation between body weight of the 21 d and vaginal opening time in IUGR rats，Rs = -0.174，P = 0.039. The besity rates of puberty and adulthood of IUGR rats in SL-IUGR group were 28.33% and 21.67%，which were significantly higher than those in CF-IUGR group（7.5%，6.25%；P = 0.001，0.007）. The weight growth rate of adolescent obese IUGR rats at 7 and 21 d was higher than that of non-adolescent obese rats，and the weight growth rate of adult obese IUGR rats at 7 and 35 d was higher than that of non-adolescent obese rats. The difference was statistically significant（P < 0.05）. Binary Logistic regression analysis of vaginal opening time and adult obesity in IUGR rats′ group OR = 0.419，P = 0.24. The time of vaginal orifice opening was not an independent factor of adult obesity. 【Conclusions】The improvement of nutrition level in the early stage of life is beneficial to weight catch-up of IUGR，and the overweight catch-up during lactation can lead to puberty and adulthood obesity of IUGR rats，as well as the advance of vaginal opening time.

[Characteristics of soil microbes and enzyme activities in different degraded alpine meadows]. / é€€åŒ–é«˜å¯’è‰ç”¸åœŸå£¤å¾®ç”Ÿç‰©åŠé ¶æ´»æ€§ç‰¹å¾.

Soil microbial biomass C and N, microbial diversities and enzyme activity in 0-10 cm and 10-20 cm soil layers of different degraded grasslands (non-degradation, ND; light degradation, LD; moderate degradation, MD; sever degradation, SD; and black soil beach, ED) were measured by Biolog and other methods. The results showed that: 1) There were significant diffe-rences between 0-10 cm and 10-20 cm soil layers in soil microbial biomass, diversities and inver-tase activities in all grasslands. 2) The ratio of soil microbial biomass C to N decreased significantly with the grassland degradation. In the 0-10 cm soil layer, microbial biomass C and N in ND and LD were significantly higher than that in MD, SD and ED. Among the latter three kinds of grasslands, there was no difference for microbial biomass C, but microbial biomass N was lower in MD than in the other grasslands. The average color change rate (AWCD) and McIntosh Index (U) also decreased with grassland degradation, but only the reduction from ND to MD was significant. There were no differences among all grasslands for Shannon index (H) and Simpson Index (D). The urease activity was highest in MD and SD, and the activity of phosphatase and invertase was lowest in ED. In the 10-20 cm soil layer, microbial biomass C in ND and LD were significantly higher than that in the other grasslands. Microbial biomass N in LD and ED were significantly higher than that in the other grasslands. Carbon metabolism index in MD was significantly lower than that in LD and SD. AWCD and U index in ND and LD were significantly higher than that in ED. H index and D index showed no difference among different grasslands. The urease activity in ND and MD was significantly higher than that in the other grasslands. The phosphatase activity was highest in MD, and the invertase activity was lowest in MD. 3) The belowground biomass was significantly positively correlated with microbial biomass, carbon metabolic index and phosphatase activity, and the urease activity was negatively correlated with microbial biomass N, H index and D index.

SpMYB overexpression in tobacco plants leads to altered abiotic and biotic stress responses.

The MYB transcription factors are involved in various plant biochemistry and physiology processes and play a central role in plant defense response. In the present study, a full-length cDNA sequence of a MYB gene, designated as SpMYB, was isolated from tomato. SpMYB encodes the R2R3-type protein consisting of 328 amino acids. The expression level of SpMYB was strongly induced by fungal pathogens. Transgenic tobacco plants overexpressing SpMYB had an enhanced salt and drought stress tolerance compared with wild-type plants, and showed significantly improved resistance to Alternaria alternate. Further analysis revealed that transgenic tobaccos exhibited less accumulation of malondialdehyde (MDA) and more accumulation of superoxide dismutase (SOD), peroxidase (POD) and phenylalanine ammonia-lyase (PAL) after inoculation with A. alternate. Meanwhile, changes in some photosynthetic parameters, such as photosynthetic rate (Pn), transpiration rate (Tr) and intercellular CO2 concentration (Ci) were also found in the transgenic tobaccos. Furthermore, transgenic tobaccos constitutively accumulated higher levels of pathogenesis-related (PR) gene transcripts, such as PR1 and PR2. The results suggested that the tomato SpMYB transcription factor plays an important role in responses to abiotic and biotic stress.