Curcuma alismatifolia was used as the test material to study the effects of controlled release fertilizers with different ratios of N-P-K and the common compound fertilizers on the growth of C. alismatifolia by measuring its plant height, stem thickness, leaf length, flowering rate and chlorophyll content.The results showed that the application of controlled-release fertilizer was more beneficial to increase the leaf length and the chlorophyll content of C. alismatifolia than compound fertilizer under the same amount and composition of fertilizer, and the best effect on the growth of C. alismatifolia was achieved on the N-K controlled-release fertilizer. Meanwhile, the application of controlled release fertilizer was more beneficial to the flowering of C. alismatifolia. The flowering rate of P-K controlled-release fertilizer was the highest, which can improve the ornamental value of C. alismatifolia. Consequently controlled release fertilizer was more conducive to the growth of C. alismatifolia.

Tomato yellow leaf curl virus (TYLCV) imposes the major threat to tomato production in Guangdong province. In order to obtain TYL (V-resistant tomato) germplasm resources, a viral infectious clone-based resistance identification method was established, and by using this method, the interaction of 103 tomato germplasm materials with the virus was then tested in this study. The results showed that among the tested tomato germplasms, 8 materials were resistant, and 14 were tolerant, to TYLCV. The obtained tomato resources may be used for the breeding of virus-resistant varieties, as well as further study on the potential mechanism related to tomato TYLCV resistance.

How to maintain egg production persistency for broiler was the most critical problem in poultry industry. Oxidative stress was known to cause ovarian function decline in female chicken．The relationship between oxidative stress and reproductive performance in late laying period was still unknown．Six individuals at their laying age of 15 weeks and 22 weeks were randomly selected for the determination of 6 antioxidant index, including catalase (CAT), superoxide dismutase (SOD), nitric oxide synthase (NOS), nitric oxide (NO), malondialdehyde (MDA) and glutathione peroxidase (GSH-Px) among serum, liver and ovarian tissues. Our results showed that there were no significant differences in ovarian index and the number of prehierarchical follicles (big white follicles and small yellow follicles) between hens at 15 weeks and 22 weeks of laying age. SOD, CAT, NO and GSH-Px in serum and liver tissue of breeders were significantly decreased with the increase of laying week (P<0.05 or P<0.01). GSH-Px, and CAT in liver of breeders at 15 weeks of laying were significantly higher than those at 22 weeks of laying (P<0.05), while MDA and NOS were significantly lower than that at 22 weeks of laying (P<0.05). There were no significant differences in the 6 antioxidant indexes of ovarian tissue. Compared with the hens at 22 weeks of laying age, the concentration of both Gonadotrophin Releasing Hormone (GnRH) and Estradiol (E2) in serum were significantly higher at 15 weeks of laying age（P<0.05 or P<0.01). The Correlation anaylsis showed that there were significant positive correlation beween serum GnRH concentration and 3 antioxidant indexes (SOD, CAT and NO), between serum E2 concentration and 2 antioxidant indexes (CAT and NO). Our results indicated that the accumulation and aggravation of oxidative damage in serum and liver seems to relate to the decline of productive performance after laying peak.

In order to detect and identify the pathogen of the skin ulceration disease of Plectropomusleopardus, the bacteria were isolated from diseased fish and identified as Vibrio harveyi basing on morphological characteristics, physiological and biochemical identification as well as 16S rRNA gene sequence analysis. The drug sensitive tests of 18 kinds of antibiotics were carried out using Kirby-bauer way. Results showed that the bacteria were most sensitive to Florfenicol, intermediate sensitive to 6 antibiotics including Cefazolin and Neomycin, and resistant to 11 antibiotics including Carbenicillin and Cefalexin. The minimum inhibitory concentration (MIC) of 4 selected antibiotics were also determined using double dilution method. The result revealed that the Florfenicol showed the best inhibiting effect among the 4 antibiotics and the MIC was 0.5200 μg/mL.

To investigate the molecular phylogenetic relationships of Scarus, partial sequences of COⅠ genes from 16 parrotfish were obtain by PCR amplification and sequencing. Combining with two COⅠ sequences of Chlorurus species from NCBI, genetic distances among different parrotfish were computed using MEGA7.0 software, and the phylogenetic trees were constructed basing on Neighbor joining and Maximum likelihood method. Results showed that: 18 parrotfish mainly formed three clades, genus Cetoscarus formed a separate clade, which was located at the base of the phylogenetic tree; Genus Scarus had a high evolutionary status and was located at the top of the tree, while genus Chlorurus was between the two Cetoscarus and Scarus. Chlorurus gibbus and Chlorurus sordidus were not grouped within the genus Scarus, but were clustered inside the genus Chlorurus, which supported the taxonomic view that they were classified into Chlorurus. The phylogenetic relationship between Scarus schlegeli and Scarus psittacus was close, but the COⅠ genetic distance between them was 0.085, higher than the species identification critical value (0.020), indicating that they were two independent species. The COⅠ genetic distance between Scarus rivulatus and Scarus globiceps was 0.017, which was less than the critical value (0.020). But there were great differences in morphology, excluding the possibility of homonymy, it might be natural hybridization or gene penetration between them.

Extreme temperature can reflect the trend of climate change. In depth analysis of the temporal and spatial characteristics of extreme temperature could predict the occurrence of various extreme weather events more accurately, and provide scientific reference for actively coping with extreme weather event. Based on the daily maximum and minimum temperature data of 36 stations in Guangdong province from 1961 to 2019, the spatio-temporal characteristics of extreme temperature in Guangdong province during the past 60 years were explored in this paper，by using RClimDex model, Mann-Kendall non-parametric test method and Pearson correlation analysis. Results showed that the inter-annual trend rates of the extreme temperature index in Guangdong province have been increasing in the past 60 years, and exhibited the most obvious increase in the past 10 years, meaning a significant warming trend of the extreme temperature in Guangdong province. The time of mutations in TXx and TNn occurred in the late 1990s and early 1980s, and the extreme low temperature indexes TNn and TNx were the first to show an upward trend. In terms of spatial distribution, the temperature of TXx increased with the distance to the coastline, while TXn and TNn showed the opposite variations. For TNx, the higher the latitude was, the lower the temperature was. The extreme temperature had the characteristics of sea and land zonality and latitude zonality. The variation trend of extreme temperature in different regions of Guangdong province was similar with that of the whole province, but the Pearl River Delta region exhibited a faster increasing trend. Extreme temperature indices were correlated with both natural and socio-economic factors, while latitude and population had greater impacts.

In order to judge the progress of agricultural modernization in Guangdong Province, its trends was analyzed and its shortcomings was identified, when the entropy method and the multi-index comprehensive evaluation method was used to evaluate the development level of agricultural modernization in Guangdong Province and various prefecture-level cities. The results showed that the level had developed from the initial realization stage to the basic realization stage from 2014 to 2019. In 2014, the development of each prefecture level city was in the mixed situation of initial stage, preliminary realization stage and basic realization stage. By 2019, all of prefecture level cities had entered the basic realization stage. In reality, Guangzhou, Zhuhai and other cities had reached the stage of full realization. Then the obstacle factors in Guangdong Province and each prefecture-level city were analyzed to identify the main obstacle factors in the development of agricultural modernization, and relevant suggestions was put forward.

Taking 503 villagers from 1 street and 6 towns in Nanhai, Guangdong as the survey objects, questionnaire survey method and Logistic regression model were used to analyze the villagers-cognition and willingness and the influencing factors to the system of market entering preparation of rural collective operating construction land in Nanhai, Guangdong. The results showed that villagers had a weak willingness to reconditioning rural collective commercial construction land to the market with only 23.3% accepted. There were three significant factors that affected the villagers' response to the market entering preparation of rural collective commercial construction land: the geographical location of the village where the villagers'families live, the villagers'understanding of the market entering preparation system and their expectation of the land into the market.

CPI and PPI are two main criteria to judge the price level and macroeconomic trend. There is no consistent conclusion about the debate on the conduction direction of CPI and PPI. The monthly series of PPI and CPI were used to analyze the conduction effect and action duration based on Autoregressive integrated moving average-X （ARIMAX）model, supplemented by Granger causality test. The results showed that there was a two-way lagging conduction between PPI and CPI in China; The influence of PPI was transmitted to CPI after 1 month, and the influence of CPI was transmitted to PPI after 2 months; The effect duration of PPI on CPI was short and lasted for 2 months, and the effect duration of CPI on PPI lasted for a long period. Therefore, we should adjust from both monetary and fiscal policies, establish a price index monitoring system, and promote supply-side structural reform, so as to reduce price fluctuations and promote the smooth operation of the economy.

By using B-spline for stretching and compression transformation, a kind of piecewise polynomial function could be obtained and approximate δ-function. On the basis, a new quasi interpolation was constructed, while the corresponding errors were analyzed and numerical experiments were carried out. The results of numerical examples showed that the new quasi-interpolation on the basis of B-spline had good approximation effect.

Using the impulse stabilization theory, a certain type of automobile system could achieve the expected stabilization effect under the impulse interference when the coordinated braking control could not achieve the system stability. Using the Lyapunov method and the constant variation method formula, the stability condition of the vehicle system under the pulse action was that: A(t) was continuous on ［t0,+∞), and ∫∞t0|~C(t)|2dt<+∞.