马槟榔种子中的葡糖硫甙硫酸酯和葡糖硫甙酶

自马槟榔(Capparis masaikai L(?)vl.)种子中分离出一种新的葡糖硫甙硫酸酯,即2-羟乙基葡糖硫甙硫酸酯(2-hydroxyethylglucosinolate),得率为干种仁的3％;在葡糖硫甙酶(pH 6.0)作用下,酶解产物为(口恶)唑烷硫酮(oxazolidine-2-thione)。马槟榔种子中的葡糖硫甙酶用1N氯化纳提取,经硫酸铵沉淀,通过葡聚糖G50凝胶过滤层析和羧甲基纤维素离子交换层析,得到纯制品。测得该酶分子量Mr=116 kD,是由二个相近的亚基组成,等电点pI=5.05。与文献中报道从十字花科植物中提取的葡糖硫甙酶是分子量为140 kD的糖蛋白不同,该酶未检出含糖。     

Leaf age effects on photosynthetic rate, transpiration rate and nitrogen content in a tropical dry forest

This study examines the effect of leaf age on photosynthesis, transpiration and nitrogen concentration in four deciduous (DC) and two evergreen (EG) species coexisting in a tropical dry forest of Venezuela. Leaf age was characterized on the basis of leaf chorophyll, nitrogen content, and construction and maintenance costs. The mean leaf area-based nitrogen concentration (N) in EG was about twice that in DC species. A leaf age effect was observed in both DC and EG species, with largest N concentration in mature leaves. Fractional leaf N allocation to chlorophyll was higher in the DC than in the EG species. Differences in the construction costs of leaf mass between the youngest and the oldest leaves averaged from 2.14 to 1.55 g glucose g⁻¹ dry weight. Although variation in area-based leaf maintenance and construction costs between DC and EG species existed, they were, nevertheless, positively correlated. Individual data sets, for each species, indicated that leaf N and maximum rate of photosynthesis (A_max) were linearly related. Nitrogen use efficiency (NUE) and water use efficiency (WUE) tended to be higher in mature leaves than in expanding and old leaves. Moreover, DC species always had higher NUE than EG species. Intercellular to ambient pressures of CO₂ (P_i/P_a) were related to WUE in a negative manner. Higher P_i/P_a values were observed in expanding and old leaves. Leaf age effect on photosynthesis was, therefore, due to greater decline of carbon fixation capacity by mesophyll tissue relative to the decline in stomatal conductance in youngest and oldest leaves.     

Patterns in Volatile Emission of Different Aerial Parts of Caper (Capparis spinosa L.)

We analyzed the spontaneous volatile emission of different aerial parts of the caper (Capparis spinosa L.) by HS‐SPME‐GC/MS. We identified 178 different compounds of which, in different proportions based on the sample type, the main ones were (E)‐β‐ocimene, methyl benzoate, linalool, β‐caryophyllene, α‐guaiene, germacrene D, bicyclogermacrene, germacrene B, (E)‐nerolidol, isopropyl tetradecanoate, and hexahydrofarnesyl acetone. The multivariate statistical analyses seem to point out that the parameter leading the emission patterns is the function of the analyzed sample; the flower samples showed differences in the emission profile between their fertile and sterile portions and between the other parts of the plant. The green parts emission profiles group together in a cluster and are different from those of seeds and fruits. We also hydrodistilled fully bloomed caper flowers, whose volatile oil showed significant differences in the composition from those of other parts of the plant reported.     

马槟榔甜味蛋白的研究Ⅱ.甜蛋白Ⅱ和甜蛋白Ⅰ的比较

从马槟榔(Capparis masaikai Levl.)种子分离鉴定了二种甜蛋白:甜蛋白Ⅰ(mabinlinⅠ或MaⅠ)分子量MW11600,等电点pI 11.8;甜蛋白Ⅱ(mabinlinⅡ或MaⅡ)MW10400,pI 11.3。另一组分mabinlinⅢ MW10200,pI 11.8,可能是提取过程产物。MaⅡ有84个氨基酸残基,比MaⅠ少15个。它们有80个氨基酸残基是共同的,都是缺丝氨酸和蛋氨酸的单一多肽链。MaⅠ还缺赖氨酸和酪氨酸。测不出有自由SH基。在8M尿素中用巯基乙醇还原处理,两种甜蛋白分子都可转变为二聚体而失去甜味。 自去壳脱脂的种子干粉中提取MaⅠ和MaⅡ的得率依所用溶剂和提取条件而异。用50％丙酮水溶液提取,继用CM-纤维素分离,甜蛋白的得率达13％。用水或0.1N pH6.2磷酸缓冲液提取,得率低于1％。     

Structure and Development of the Axillary Complex and Extrafloral Nectaries in Capparis retusa Griseb.

Abstract: The structure, organization and development of the axillary complex and extrafloral nectary in Capparis retusa Griseb. was analysed for the first time. The axillary complex presents three uniserial descending buds. Subordinated shoots originate from the distal and middle bud, while the proximal bud is usually quiescent. Close to the top of the axillary complex there is a subglobulous and umbilicated extrafloral nectary, normally visited by nectivore ants; a chronological coincidence between secretion, production and ant patrolling activities has been observed. The nectary structure differentiates at the second caulinar node, from an axillar meristem separated from the surrounding cells by a shell zone. On the fourth node a remarkably developed nectary primordium can be observed, inside which procambial strands develop acropetally. In the central region of the nectary primordium homogenous parenchyma differentiates progressively, later acquiring characteristics of nectariferous tissue. The mature nectary is vascularized by xylem and phloem, and the procambial differentiation is completed in a basipetal way. The first serial bud differentiates at the third node, from meristem cells near the base of its supporting leaf. The complex nodal structure with three buds completes its development at the eighth caulinar node. Ramular traces are observed as vascular semicylinders penetrating into the base of the buds to constitute a vascular system similar to that of the shoot. The scheme is repeated in the extrafloral nectary, giving rise to prolific branching in the periphery of the nectariferous tissue.     

Adaptive significances of sexual system in andromonoecious Capparis spinosa (Capparaceae)

The sexual system of the perennial shrub Capparis spinosa L. (Capparaceae), which is distributed in arid deserts of northern Xinjiang, was investigated. The main results can be summarized as follows. (1) The species is andromonoecious, i.e. individuals possess both male and perfect flowers. Stamens of two floral morphs are normal and can be divided into long and short ones in each flower. The perfect flowers have well developed pistils, but male flowers have aborted pistils and only function as males. (2) There were very significant differ-ences among the populations in daily ratio of the two floral morphs, number of long and short stamens of perfect flowers and length of filaments and anthers of short stamens in male flowers (P<0.01), but no significant differ-ences occurred in biomass of floral organ (P>0.05). (3) Anthesis was nocturnal and lasted 15–16 h. Both male and perfect flowers opened about 18:00 at dusk. The number of two floral morphs produced on each individual was indeterminate every day during flowering, which would make the individual temporally androdioecious. However, the total number of male flowers was more than that of perfect flowers within the population every day. (4) The P/O ratios of perfect flowers in three populations were 1.57×104, 1.65×104 and 1.71×104. There was no significant difference in pollen numbers (P>0.05) within population between male and perfect flowers or between long and short stamens, and also no significant difference among the populations in pollen numbers of male and perfect flowers, and in ovule numbers and P/O ratios of perfect flowers (P>0.05). (5) Dynamic curves of pollen viability of long and short stamens in the two floral morphs were similar in three populations. Pollen longevity of both long and short stamens was about 18–20 h, and duration of stigmatic receptivity was about 16–18 h. (6) Floral visitors were hymenopterous and lepidopterous insects. There was a total of seven species of floral visitors in the three populations. The activities of them were greatly affected by the climate of the desert environment. (7) Perfect flowers were not apomictic and could produce fruits after self-pollination (autogamy and geitonogamy) and cross-pollination; thus they had a mixed mating system. These results suggest that the sexual system of andro-monoecy may reflect an environment-heredity interaction in C. spinosa. The male flowers increase the number of pollen grains, the P/O ratio and enhance male fitness of individuals. They also increase the floral display and consequently effect cross pollination by attracting more pollinators that bring cross-pollen to the stigmas of per-fect flowers, thus increase outcrossing rate and female fitness of individuals, which insure reproductive success of C. spinosa in the extreme desert environment.     

(6S)-Hydroxy-3-oxo-alpha-ionol glucosides from Capparis spinosa fruits

Two new (6S)-hydroxy-3-oxo-alpha-ionol glucosides, together with corchoionoside C ((6S,9S)-roseoside) and a prenyl glucoside, were isolated from mature fruits of Capparis spinosa. The structures were established on the basis of spectroscopic, chiroptic and chemical evidence. In addition, the 13C-resonance of C-9 was found to be of particular diagnostic value in assigning the absolute configuration at that center in ionol glycosides. The alpha-ionol derivatives are metabolites of (+)-(S)-abscisic acid.     

刺山柑70 kD热休克蛋白基因克隆及原核表达

以干旱区特有的抗逆性植物刺山柑为材料,利用RT-PCR结合cDNA末端快速扩增(rapid amplification of cDNA ends,RACE)方法,克隆了一个HSP70基因,将该基因进行原核表达,通过对大肠杆菌进行温度胁迫实验,并计算存活率来验证该基因对细胞的保护作用.结果表明:该基因全长2 202 bp,开放阅读框共1 950 bp,编码649个氨基酸,表达产物分子量为71.044 6 kD;序列分析表明,该基因属于HSP70基因家族,将该基因命名为CsHSP70,并提交到GenBank,登录号为EU574936.构建了CsHSP70基因的原核表达载体,并使重组质粒pGEX-4T-2-CsHSP70在大肠杆菌中异源表达,对大肠杆菌进行温度胁迫实验结果显示,在高温(50℃)和低温(4℃)条件下,转重组质粒的大肠杆菌在两种胁迫下存活率均高于对照,说明在温度胁迫下CsHSP70对大肠杆菌细胞具有保护作用.