光肩星天牛种组研究现状

评述了我国光肩星天牛种组种类的外部形态和外生殖器主要鉴别特征、寄主、地理分布、起源及其演化。光肩星天牛主要分布在山西吕粱山、太行山以东的广大平原地区 ,寄主广泛 ,主要有榆、复叶槭、杨、柳、五角枫等。黄斑星天牛主要分布在秦岭以北 ,山西吕粱山、太行山以西的陕甘宁地区 ,向东已扩展到河南、河北 ;主要危害杨树 ,也为害柳、榆。四川星天牛主要分布于秦岭以南的云、贵、川地区 ,主要危害柳树 ;在这里至今还没有发现光肩星天牛和黄斑星天牛。     

Lipids in xylem sap of woody plants across the angiosperm phylogeny

Lipids have been observed attached to lumen-facing surfaces of mature xylem conduits of several plant species, but there has been little research on their functions or effects on water transport, and only one lipidomic study of the xylem apoplast. Therefore, we conducted lipidomic analyses of xylem sap from woody stems of seven plants representing six major angiosperm clades, including basal magnoliids, monocots and eudicots, to characterize and quantify phospholipids, galactolipids and sulfolipids in sap using mass spectrometry. Locations of lipids in vessels of Laurus nobilis were imaged using transmission electron microscopy and confocal microscopy. Xylem sap contained the galactolipids di- and monogalactosyldiacylglycerol, as well as all common plant phospholipids, but only traces of sulfolipids, with total lipid concentrations in extracted sap ranging from 0.18 to 0.63 nmol ml⁻¹ across all seven species. Contamination of extracted sap from lipids in cut living cells was found to be negligible. Lipid composition of sap was compared with wood in two species and was largely similar, suggesting that sap lipids, including galactolipids, originate from cell content of living vessels. Seasonal changes in lipid composition of sap were observed for one species. Lipid layers coated all lumen-facing vessel surfaces of L. nobilis, and lipids were highly concentrated in inter-vessel pits. The findings suggest that apoplastic, amphiphilic xylem lipids are a universal feature of angiosperms. The findings require a reinterpretation of the cohesion-tension theory of water transport to account for the effects of apoplastic lipids on dynamic surface tension and hydraulic conductance in xylem.     

A technique for measuring xylem hydraulic conductance under high negative pressures

A technique for measuring hydraulic conductances of excised xylem segments exposed to high negative pressures is described. A centrifugal force is used to generate negative pressures (P) in the sample and to create a positive hydrostatic pressure difference (ΔP) between its two ends. ΔP forces water through the sample at a flow rate (F) determined optically during centrifugation. The sample hydraulic conductance k is derived from F and ΔP. The sample vulnerability curve is given by the dependence of k on P. Results for Cedrus atlantica Manetti and Laurus nobilis L. shoots are given. The technique is appropriate for the analysis of xylem refilling under negative pressure.     

苹婆种子营养及抗氧化活性

介绍了一种原产华南、种子可食的木本植物——苹婆的生物学特性,并以广西苹婆（Sterculia nobilisSmith）种子为材料,对其营养成分进行了测定。通过测定其多酚提取物的还原力和金属螯合力,以及对1,1-二苯基-2-三硝基苯肼（DPHH）自由基、羟自由基和超氧阴离子自由基的清除能力,探讨了苹婆种子的抗氧化活性。结果显示：苹婆种子营养丰富,含有18种氨基酸,富含酚类物质。其中,淀粉含量60.42 g/100 g FW、蛋白质20.32 g/100 g FW、脂肪2.18 g/100 g FW、氨基酸2.36 g/100 g FW、铁136.86 mg/g FW、维生素C 7225μg/100 g FW;总酚含量为401.84μg/mL没食子酸。苹婆种子多酚提取物有较强的还原力,金属螯合力,以及DPPH自由基、羟自由基和超氧阴离子自由基清除能力,在0～50μg/mL浓度范围,苹婆抗氧化能力与抗坏血酸或乙二胺四乙酸（EDTA）相当。苹婆种子营养全面,具有较强的抗氧化能力,苹婆是很有潜力的功能食品来源植物。     

Fumigant toxicity of Laurus nobilis and Myrtus communis essential oils on larvae and adults of the Red flour beetle,Tribolium castaneum Herbst (Col.: Tenebrionidae)

Considering the invasion to food commodities by insects and harmful effect of chemical pesticides, essential oils are among the best known substances tested against stored product pests. These compounds may act as fumigants, contact insecticides, repellents or anti-feedants. In present study, fumigant toxicity of essential oils from Laurus nobilis L. and Myrtus communis L. was assessed on larvae and adults of Tribolium castaneum Herbst at 27?±?2?°C, 60?±?5% RH in darkness. Each essential oil was tested in five concentrations with three replicates. The LC₅₀ values of L. nobilis and M. communis against adults of beetle were calculated 243.78 and 56.11?μl/l and LC₉₅ values for them were 685.85 and 144.01?μl/l, respectively. For the larvae of T. castaneum, the LC₅₀ values for L. nobilis and M. communis were 211.64 and 69.63 and LC₉₅ values were 656.84 and 183.65?μl/l, respectively. Results showed that these essential oils may have potential as botanical control agents against larvae and adults of T. castaneum.     

Leaf internal diffusion conductance limits photosynthesis more strongly in older leaves of Mediterranean evergreen broad-leaved species

Leaf age-dependent changes in structure, nitrogen content, internal mesophyll diffusion conductance (g_m), the capacity for photosynthetic electron transport (J_max) and the maximum carboxylase activity of Rubisco (V_cmax) were investigated in mature non-senescent leaves of Laurus nobilis L., Olea europea L. and Quercus ilex L. to test the hypothesis that the relative significance of biochemical and diffusion limitations of photosynthesis changes with leaf age. The leaf life-span was up to 3 years in L. nobilis and O. europea and 6 years in Q. ilex. Increases in leaf age resulted in enhanced leaf dry mass per unit area (M_A), larger leaf dry to fresh mass ratio, and lower nitrogen contents per dry mass (N_M) in all species, and lower nitrogen contents per area (N_A) in L. nobilis and Q. ilex. Older leaves had lower g_m, J_max and V_cmax. Due to the age-dependent increase in M_A, mass-based g_m, J_max and V_cmax declined more strongly (7- to 10-fold) with age than area-based (5- to 7-fold) characteristics. Diffusion conductance was positively associated with foliage photosynthetic potentials. However, this correlation was curvilinear, leading to lower ratio of chloroplastic to internal CO₂ concentration (C_c/C_i) and larger drawdown of CO₂ from leaf internal air space to chloroplasts (Δ_C) in older leaves with lower g_m. Overall the age-dependent decreases in photosynthetic potentials were associated with decreases in N_M and in the fraction of N in photosynthetic proteins, whereas decreases in g_m were associated with increases in M_A and the fraction of cell walls. These age-dependent modifications altered the functional scaling of foliage photosynthetic potentials with M_A, N_M, and N_A. The species primarily differed in the rate of age-dependent modifications in foliage structural and functional characteristics, but also in the degree of age-dependent changes in various variables. Stomatal openness was weakly associated with leaf age, but due to species differences in stomatal openness, the distribution of total diffusion limitation between stomata and mesophyll varied among species. These data collectively demonstrate that in Mediterranean evergreens, structural limitations of photosynthesis strongly interact with biochemical limitations. Age-dependent changes in g_m and photosynthetic capacities do not occur in a co-ordinated manner in these species such that mesophyll diffusion constraints curb photosynthesis more in older than in younger leaves.     

Hydraulic architecture of leaf venation in Laurus nobilis L.

Veins are the main irrigation system of the leaf lamina and an understanding of the hydraulic architecture of the vein networks is essential for understanding leaf function. However, determination of leaf hydraulic parameters is challenging, because for most leaves the vein system is reticulate, contains a hierarchy of different vein sizes, and consists of leaky conduits. We present a new approach that allows for measurements of pressure differences between the petiole and any vein within the leaf. Measurements of Laurus nobilis leaves indicate that first‐ and second‐order veins have high axial conductance and relatively small radial permeability, thus allowing water to reach distal areas of the leaf with only a small loss of water potential. Higher order veins tend to be more hydraulically resistant and permit greater radial leakage. This design allows for a relatively equitable distribution of water potential and thus reflects the capacity of the venation to provide a relatively homogeneous water supply across the leaf lamina, with only the leaf margins being hydraulically disadvantaged relative to the rest of the leaf.     

Ten polymorphic dinucleotide microsatellite markers of the noble scallop Chlamys nobilis

The primers flanking 22 microsatellites isolated from a genomic library enriched for (CA)_n and (GA)_n were designed in the noble scallop Chlamys nobilis. Ten primer pairs provided clear and polymorphic amplification products. Based on characterization with 48 individuals, the number of alleles ranged from three to six. The values of observed heterozygosity and expected heterozygosity varied from 0 to 0.88 and from 0.29 to 0.76, respectively. No significant linkage disequilibrium between pairs of loci was found and six of 10 loci conformed to the Hardy–Weinberg equilibrium. These markers are therefore potentially useful for studies of the population structure of the species.