Population Structure and Growth Patterns of Opuntia echios var. gigantea along an Elevational Gradient in the Galípagos Islands1

Cacti growing in forests potentially experience growth limitation due to reduced light availability. To test this hypothesis, we studied the population structure of Opuntia echios var. gigantea at 15 sites on the south side of Isla Santa Cruz, Galípagos Islands, Ecuador. Populations were located in communities ranging from arid scrub at low elevations to closed‐canopy tropical dry forest at higher elevations. Ordination confirmed the existence of a strong elevation‐vegetation gradient. Opuntia abundance peaked at lower elevations (ca 30 m), with lower densities in closed‐canopy sites. For populations in scrub vegetation, density declined fairly regularly with plant height. Populations in forested sites had few plants of intermediate height, suggesting periodic recruitment. Scrub populations had random dispersion, while those in forests were aggregated. The change in spatial pattern may be related to a change in primary reproductive mode from asexual propagation via fallen fruits to propagation via fallen cladodes. Height was significantly correlated with stem diameter. Intercepts of these relationships increased toward higher elevations, probably in response to the increasing height of the surrounding canopy.     

Nutrient fluxes from water to land: seabirds affect plant nutrient status on Gulf of California islands

Energy and nutrient fluxes across habitat boundaries can exert profound direct and indirect effects on the dynamics of recipient systems. Transport from land to water is common and well studied; here, we document a less recognized process, substantial flows from water to land. On hyperarid, naturally nutrient poor islands in the Gulf of California, nutrient input via seabird guano directly increases N and P concentrations up to 6-fold in soils; these nutrients enrich plants. Nutrients in a long-lived cactus, a short-lived shrub, and annuals were 1.6- to 2.4-fold greater on bird versus nonbird islands. Because plant quality affects consumer growth and reproduction, we suggest that nutrient enrichment via guano ramifies to affect the entire food web on these islands. Received: 6 April 1998 / Accepted: 6 October 1998     

“米邦塔”仙人掌营养及功能成分分析

本文对“米邦塔”仙人掌不同部位的主要营养成分及功能特性进行研究。实验结果表明“米邦塔”仙人掌属于典型的高钾低钠型植物,皮、渣、汁中钾钠含量比分别为56．1：1,36．5：1,13．4：1;皮、渣中黄酮含量较高,其含量分别达到0．231％,0．164％;新鲜仙人掌汁中SOD（超氧化物歧化酶）活力高达103．79U／mL,多糖含量高达1．96％。     

仙人掌属植物化学成分及药理作用研究进展

本文较全面地综述了中药仙人掌的本草考证、仙人掌属植物国内外对其化学成分及药理活性研究的进展。     

Betanin a betacyanin pigment purified from fruits of Opuntia ficus-indica induces apoptosis in human chronic myeloid leukemia Cell line-K562

Betalains are water-soluble nitrogenous vacuolar pigments present in flowers and fruits of many caryophyllales with potent antioxidant properties. In the present study the antiproliferative effects of betanin, a principle betacyanin pigment, isolated from the fruits of Opuntia ficus-indica, was evaluated on human chronic myeloid leukemia cell line (K562). The results show dose and time dependent decrease in the proliferation of K562 cells treated with betanin with an IC(50) of 40 microM. Further studies involving scanning and transmission electron microscopy revealed the apoptotic characteristics such as chromatin condensation, cell shrinkage and membrane blebbing. Agarose electrophoresis of genomic DNA of cells treated with betanin showed fragmentation pattern typical for apoptotic cells. Flow cytometric analysis of cells treated with 40 microM betanin showed 28.4% of cells in sub G0/G1 phase. Betanin treatment to the cells also induced the release of cytochrome c into the cytosol, poly (ADP) ribose polymerase (PARP) cleavage, down regulation Bcl-2, and reduction in the membrane potentials. Confocal microscopic studies on the cells treated with betanin suggest the entry of betanin into the cells. These studies thus demonstrate that betanin induces apoptosis in K562 cells through the intrinsic pathway and is mediated by the release of cytochrome c from mitochondria into the cytosol, and PARP cleavage. The antiproliferative effects of betanin add further value to the nutritional characteristics of the fruits of O. ficus-indica.     

墨西哥仙人掌植物内生真菌的研究Ⅰ.内生真菌分离及其抗菌活性筛选

从一种墨西哥仙人掌[Opuntiamicrodasys(Lehm .)Pfeiff]的肉质茎中分离获得31株内生真菌,经形态观察分类鉴定为3个目、3个科、14个属。同时选择2 2种病原微生物作为指示菌进行抑菌试验,研究其抗菌活性。结果表明:3株仙人掌内生真菌分别对细菌、植物病原真菌和皮肤致病真菌多种病原微生物有较为明显的抑制生长作用。     

仙人掌红色素的研究

仙人掌红色素是从仙人掌科(Gactaceae)仙人掌属植物(Opuntia dillenii (Ker-Gawl.) Hawl)的成熟果实中提取的一种天然食用色素。在pH2—8范围内呈鲜艳的紫红色。色素的主要化学成份是甜菜花青素(betacyanines):甜菜甙(betanin)。本色素为水溶性色素,对光、热不稳定,抗坏血酸能提高色素的热稳定性。     

Spine influences on PAR interception, stem temperature, and nocturnal acid accumulation by cacti

Abstract. The influence of spines on nocturnal acid accumulation was examined for two Crassulacean acid metabolism plants, the barrel cactus Ferocactus acanthodes (Lemaire) Britton & Rose var. lecontei (Engelm.) Lindsay and the cylindropuntia Opuntia bigelovii Engelm. var. bigelovii. The ambient photo-synthetically active radiation (PAR) required for 90% saturation of nocturnal acid accumulation by O. bigelovii was 23 mol m^?2 d^?1 for stems that were 32% shaded by spines and 16 mol m^?2 d^?1 when the spines were removed. For F. acanthodes, 90% saturation occurred for an ambient PAR of 45 mol m^?2 d^?1 where the stem was 78% shaded by spines and 21 mol m^?2 d^?1 when the spines were removed. For comparison, the ambient PAR averaged 21 mol m^?2 d^?1 at various times of the year and stem positions for O. bigelovii fully exposed to solar irradiation. Although spines can reflect some PAR toward the stem surface, their presence decreases the PAR incident on the stem surface, thereby decreasing the nocturnal acid accumulation. For O. bigelovii, periodically removing the spines led to a 60% greater increase in stem volume over 2^1/2 years. The effect of variation in spine-shading on stem surface temperature was determined for F. acanthodes using computer simulations and an energy budget model. A substantial reduction in daytime stem temperatures and a smaller increase in night-time temperatures as the spine-shading increased had very little influence on nocturnal acid accumulation for both winter and summer days. Thus, the main effect of spines on the metabolism of cacti is apparently to reduce the PAR incident on the stem surface and thereby to reduce productivity.     

Calcium oxalate crystals inOpuntia ficusindica (L.) mill.: Development and relation to mucilage cells — A stereological analysis

Summary In the succulent tissue ofOpuntia ficusindica development of calcium oxalate crystals was followed from the shoot apex to its base, using stereological analysis. The stereological parameters relating to the crystal cells were compared with those of mucilage cells, of the same tissue. A fairly monotonic relation between the stereological parameters of the two populations was noted. The possible physiological relation between the two cell populations is discussed.     

仙人掌中槲皮素提取条件的正交设计优选

采用浸渍法和回流法从仙人掌中提取槲皮素。试验表明:回流法提取的效率高于浸渍提取法。通过对溶剂种类、浓度、回流提取时间和仙人掌粉末粒度4个因素的选择,并以L9(34)正交设计安排实验,得出最佳回流提取工艺为:过60目筛的干燥仙人掌粉末加浓度为95%甲醇回流3 h。