生态梯度轴(EGA)用于林木生态遗传的研究——CA方法估算EGA(CA_1)和EGA(r~2)

应用典型相关的原理和技术,将多元地理坐标和生态因子降维成1元,研究提出2个生态梯度轴(EGA);EGA(CA_1)和EGA(r~2)。通过白榆20个种源的2个EGA估算,它们与6个环境因子平均相关系数为0.8551和0.8804,复相关系数0.9998和0.9985,很好地综合了诸环境因子在对群体7个性状分析结果,EGA能很好描述梯度变异,证明了白榆种群属于连续变异模式。     

浙江金华北山植物区系地理的研究

金华北山约有种子植物１４０科、５１９属、１０５２种。区系成分中,以北温带、泛热带、东亚三种成分为主,植物区系具明显的亚热带性质。以植物地理成分为指标,对金华山与全国其它１４个山地的植物区系进行了模糊聚类分析。结果表明,庐山、天目山植物区系与浙南一闽北的九龙山、武夷山植物区系之间无明显的分界线。     

Terpenoids from Euphorbia helioscopia and Their Cytotoxic Activities against H1975 Cells

Three previously undescribed diterpenoids, helioscopnoids A–C, and eight known compounds were isolated from the whole plants of Euphorbia helioscopia. Their structures were established by extensive analysis of spectra and data comparison with previous literatures. Among them, compound 4 was identified as 24,24-dimethoxy-25,26,27-trinoreuphan-3β-ol with revised configurations of C-13, C-14, and C-17 (13R*, 14R*, 17R*). Cytotoxicity assays revealed that all compounds exhibited varying levels of cytotoxicity against H1975 cells, with compound 9 displaying the most potent activity, as indicated by cell viability rates of 18.13 % and 20.76 % at concentrations of 20 μM and 5 μM, respectively. This study expands the understanding of E. helioscopia terpenoids’ structural diversity and biological activities, contributing to the exploration of potential therapeutic applications.     

The legacy effect of biochar application on soil nitrous oxide emissions

Existing studies suggest that biochar application can reduce soil nitrous oxide (N₂O) emissions, mainly based on short-term results. However, it remains unclear what the effects (i.e., legacy effects) and underlying mechanisms are on N₂O emissions after many years of a single application of biochar. Here, we collected intact soil columns from plots without and with biochar application in a subtropical tea plantation 7 years ago for an incubation experiment. We used the N₂O isotopocule analysis combined with ammonia oxidizer-specific inhibitors and molecular biology approaches to investigate how the legacy effect of biochar affected soil N₂O emissions. Results showed that the soil in the presence of biochar had lower N₂O emissions than the control albeit statistically insignificant. The legacy effect of biochar in decreasing N₂O emissions may be attributed to the reduced effectiveness of the soil substrate, nitrification and denitrification activities, and the promotion of the further reduction of N₂O. The legacy effect of biochar reduced the relative contribution of nitrifier denitrification/bacterial denitrification, nitrification-related N₂O production, and the relative abundance of several microorganisms involved in the nitrogen cycle. Our global meta-analysis also showed that the reduction of N₂O by biochar increased with increasing application rate but diminished and possibly even reversed with increasing experimental time. In conclusion, our findings suggest that the abatement capacity of biochar on soil N₂O emissions may weaken over time after biochar application, but this remains under further investigation.     

DISCOVERY OF VERTEBRATE FOSSILS AND PALEOLITHIC ARTIFACTS IN DANJIANG SUBMERGING AREA AND ITS IMPLICATIONS

IntheareatobefloodedinthesecondengineeringstagefortheDanjiangreservoir,wediscovered16vertebratefossillocalitiesand52Paleolithicsitesin1994,andcollected603artifactsandmanyfossils.Ofthel6new1yfoundvertebratefossillocalities,threearereptilesitesrepresentedbydinosaureggsandlimbbones,andl3producemamma1s,including4Pale0gene,2Ne0geneand7Quaternarysites'ThemammalianlocalitiesareofPale0cene,Eocene,EarlyMiocene,andPli0ceneorEarlyPleistocene,MiddleandIntePleistocene,respectively.Theyfillinsomestrat…     

Nature of Enhanced Severity of Anthurium Root Rot by Diuron Treatment for Weed Control

Diuron treatment for weed control greatly increased anthurium root rot caused by Pythium splendens, P. spinosum, P. vexans and Calonectria crotalariac. Diuron in agar medium was inhibitory to the growth of mycelium, formation and germination of sporangia of P. splendens. Sporangia of P. splendens produced in diuron-amended medium did not differ in pathogenecity to anthurium roots from those produced in diuron-free medium. When diuron was applied to kill weeds in the planting medium, the population of P. splendens in it was not decreased during the test. Diuron was inhibitory to a number of micro-organisms in the platiting medium. Exudation of anthursum roots was not increased by diuron treatment. Increase in severity of anthurium root rot by diuron treatment was similar whether the experiments were performed in the presence or absence of planting medium, suggesting that the enhancing effect of diuron on root rot is mainly due to an increase in susceptibility of the host plants.     

小麦返白系与不同基因型小麦品种杂交后代IPO表达的研究

以小麦返白系和对照矮变１号以及返白系与各不同生态类型的冬性、半冬性、春性小麦的杂交、回交Ｆ１、Ｆ２代为材料,研究这些不同基因型品种在返白期间过氧化物酶同工酶（ＩＰＯ）基因表达模式的动态变化特点。结果表明,在返白期间以返白系为母本的各杂交、回交品种的白化苗中,ＩＰＯ的个别酶分子表现了可逆的基因阻遏和去阻遏的表达现象。这种表达特点在正、反杂交后Ｆ１代中表现一致,从遗传模式上分别属于质－核互作型的分子遗     

苯甲醛对果蝇视觉联想记忆的阻断

采用飞行模拟系统,以视觉模式为线索、热惩罚为负强化因子,对于在不同发育时期经受苯甲醛处理过的果蝇的视觉飞行定向条件化进行了检验。苯甲醛气味分别作用于果蝇幼虫和成虫阶段,将阻断果蝇成虫建立视觉联想记忆的能力;雌性果蝇在处女期对苯甲醛气味的接触,会阻断其子代建立视觉联想记忆,这种视觉联想记忆的能力可以通过对其子代连续３代的正常饲养而逐渐得到恢复。     

Partial purification and characterization of an enzyme from pea nuclei with protein tyrosine phosphatase activity

A pea (Pisum sativum L.) nuclear enzyme with protein tyrosine phosphatase activity has been partially purified and characterized. The enzyme has a molecular mass of 90 kD as judged by molecular sieve column chromatography and by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Like animal protein tyrosine phosphatases it can be inhibited by low concentrations of molybdate and vanadate. It is also inhibited by heparin and spermine but not by either the acid phosphatase inhibitors citrate and tartrate or the protein serine/threonine phosphatase inhibitor okadaic acid. The enzyme does not require Ca2+, Mg2+, or Mn2+ for its activity but is stimulated by ethylenediaminetetraacetate and by ethyleneglycolbis(beta-aminoethyl ether)-N,N'-tetraacetic acid. It dephosphorylates phosphotyrosine residues on the four different 32P-tyrosine-labeled peptides tested but not the phosphoserine/threonine residues on casein and histone. Like some animal protein tyrosine phosphatases, it has a variable pH optimum depending on the substrate used: the optimum is 5.5 when the substrate is [32P]tyrosine-labeled lysozyme, but it is 7.0 when the substrate is [32P]tyrosine-labeled poly(glutamic acid, tyrosine). It has a Km of 4 microM when the lysozyme protein is used as a substrate.     

RFLP tagging of a salt tolerance gene in rice

A salt tolerant rice mutant (M-20) was obtained through selection in vitro. Its tolerance was stably inherited over eight generations and most traints between M-20 and its sensitive original 77–170 (Oryza sativa) were very similar. By deriving an F₂ population of M-20 × 77–170 and splitting every F₂ individual into two parts, with one part planted in normal conditions and another part in saline conditions, the inheritance of salt tolerance in rice was studied. Under normal conditions, there was no apparent segregation among F₂ individuals. Under saline conditions, however, the segregation of traits was obvious. According to our standards, the ratio of salt sensitive:moderately-tolerant:tolerant plants was 25:42:18, in accordance with a 1:2:1 ratio. It suggested that the improvement of salt tolerance in our materials was induced by the mutation of a major tolerant gene which showed incomplete dominance. By use of 130 RFLP probes distributed throughout the rice genome, the gene was tagged by a single copy DNA probe, RG4, which was located on chromosome 7. The genetic distance between the salt tolerant gene and RG4 was 7.0 ± 2.9 cM. Based on the split method, a method which could be currently used to evaluate the damage of salt stress in rice was proposed.