香蕉新品种“南天黄”在琼北试验研究

在海南省澄迈县香蕉产区开展抗香蕉枯萎病品种"南天黄"大田试验研究,测定果实性状变化、株产以及调查几种病害发生情况。结果表明,该品种生育期362 d,从抽蕾后至采收,可溶性糖呈增加趋势,维生素C变化反之;通过增施钾肥,最高株产达24.19 kg,枯萎病发病率仅为0.8%,与对照品种"巴西蕉"差异极显著。     

A Review and Analysis of Seismic ResponseSpectra of Elastic-Plastic Structures

The research on seismic response spectra of Elastic-Plastic structures has gained a lot of useful results with the development of the research on seismic response of elastic-plastic structures.This paper discusses the various kinds of elastic-plastic response spectra and points out the key problem which must be solved for their use in seismic design.     

四川盆地紫色母岩养分风化释放

Purplish soils having high fertility with mineral nutrients inherited from the parent rock are widely distributed in the hills along the Yangtze River, especially in the Sichuan Basin. Pot and field weathering experiments were conducted to mimic rock weathering and nutrient release processes in order to better understand soil fertility and nutrient compensation. Three types of purplish rock formations formed in the Jurassic period, Shaximiao （J2s）, Suining （J3s）, and Penglaizhen （J3P）, as well as one type formed in the Cretaceous period, the Chengqiangyan group （K1c）, were used in this study. Results showed that the soil formation rate was in the range from 11.2 to 19.6 mm every year, and rock weathering was in the order of J3s 〉 J3P 〉 J2s 〉 K1c. Because more rock surface was exposed to sunlight and rainfall in field conditions, pot weathering was slower than field weathering. Nutrient release rates increased with rock weathering and was in the order similar to that of rock weathering： J3P 〉 J3s 〉 J2s 〉 K1c. Potassium release was the most important in all rocks; after 2 years of weathering, 19.4% to 46.9% of K was released from the initial parent rocks, which suggested that K release from weathering could meet most of the crop K requirement in purplish soils. Thus, rapid release of nutrients from weathering of purplish rocks was key to nutrient replenishment and fertility of purplish soils.     

Studies on In Vitro Flowering and Fruiting of Perilla frutescens

Influences of PGR, sucrose, and ammonium nitrate on in vitro flowering and fruiting from cotyledon explants of P. frutescens were studied. The regenerated shoots at 2-4. cm from cotyledon explants on MS medium supplemented with 0.5 mg L^-1 BA and 1.0 mg L^-1IAA were excised and transferred to MS medium containing 30 g L^-1 sucrose, 8.25 g L^-1 ammonium nitrate, and 1.0 mg L^-1 BA. Following 40 d of culture, 86.2% of them flowered and set seeds. These seeds were germinable and developed into flowering plants in the fields. This study provides a simple system for rapid breeding of P. frutescens and studying the physiological mechanism of flowering of plants.     

关于白石水库水资源量论证

白石水库是一座以防洪、灌溉、供水为主,兼顾发电、养鱼等综合利用的大(1)型水利枢纽工程.本文根据白石水库水资源现状,通过数据分析供城市用水户供、用水情况,论证了白石水库水资源量.     

Study on Relationship Between Cucumber Germplasm and Propamocarb Residue Using Subjective Rating Technique

Propamocarb(PM)residue in cucumber(Cucumis sativus L.)receives little attention.As is well known to all,high PM residue of cucumber could lead to increase in the violation rates of maximum residue limits and ultimately cause harm to human health.Knowledge of PM residue could help cucumber breeders in developing cultivars with low PM residue and improving cucumber quality.In this study,32 representative cucumber accessions(26 breeding lines and six cultivars)from different regions of China were evaluated for their PM residue in fruit and leaf to provide meaning to the subjective rating,which was highly correlated with PM residual content of fruit(r=0.97)and leaf(r=0.94).In addition,PM residual content of North China ecotype was the highest and Pickling ecotype was the lowest in fruit and leaf of cucumber.The leaf had significantly higher(P<0.01)PM residual content than the fruit,and poor correlation between leaf and fruit was represented.This study verified PM residual relationship between fruit and leaf,and laid the foundation for further identification of germplasm resources and breeding of new varieties for low PM residue of cucumber.     

Isolation and Characterization of a Cinnamoyl CoA Reductase Gene（CCR） in Pear（Pyrus pyrifolia）

Pear is a popular and commercially important fresh fruit, and its texture is related to the presence of sclereid formatted by parenchyma cell with lignification in vascular plants. Previous studies have demonstrated that content of lignin may be regulated by cinnamoyl CoA reductase（CCR） in various plants. However, the function of CCR in pears remains very limited. In the present study, we isolated a cDNA encoding CCR（PpCCR, GenBank accession No. KF999958） and its promoter（proPpCCR） from Whangkeumbae pear to investigate the function of CCR in lignin biosynthesis. PpCCR-GFP expressed in rice mesophyll protoplast demonstrated that PpCCR-GFP was localized in the cytoplasm, indicating that CCR may function in cytoplasm without localization signals. In transgenic plants carrying PpCCR, we observed higher lignin content compared with that in wild type plants, further suggesting that PpCCR can affect the lignin contents through regulating lignin biosynthesis in Arabidopsis thaliana. More studies in other plants are needed to confirm our conclusion.     

A draft sequence of the rice genome (Oryza sativa L. ssp. indica)

We have produced a draft sequence of the rice genome for the most widely cultivated subspecies in China, Oryza sativa L. ssp. indica, by whole-genome shotgun sequencing. The genome was 466 megabases in size, with an estimated 46,022 to 55,615 genes. Functional coverage in the assembled sequences was 92.0%. About 42.2% of the genome was in exact 20-nucleotide oligomer repeats, and most of the transposons were in the intergenic regions between genes. Although 80.6% of predicted Arabidopsis thaliana genes had a homolog in rice, only 49.4% of predicted rice genes had a homolog in A. thaliana. The large proportion of rice genes with no recognizable homologs is due to a gradient in the GC content of rice coding sequences.