‘辣椒95-1’保持系与雄性不育系花蜜腺的发育解剖学研究

采用扫描电镜和石蜡制片技术对'辣椒95-1'雄性不育系和同型保持系的花蜜腺及其发育过程进行了比较研究.结果表明:雄性不育系和同型保持系花蜜腺的位置、形态、结构及发育过程相似.辣椒的花蜜腺位于子房基部,围绕子房,属于子房蜜腺.蜜腺由分泌表皮和泌蜜组织组成.分泌表皮外覆角质膜,表皮无气孔分布,泌蜜组织为多层薄壁细胞.蜜腺由子房基部的外层表皮及其相邻的内侧细胞分裂、生长、分化而来.在花蕾膨大期,蜜腺细胞的细胞质较浓,已经开始积累淀粉粒和蛋白质;露冠期,分泌表皮和泌蜜组织的细胞质稀,淀粉粒和蛋白质大量增加;花蕾初放期,细胞质浓,淀粉和蛋白质的含量都非常高;盛花期,细胞质稀,液泡增大且数量增加,淀粉和蛋白质的量减少;败花期,细胞质稀,形成中央大液泡,淀粉重新积累.     

紫云英花蜜腺的发育解剖学研究

紫云英花蜜除环绕在子房基部周围,属于花托蜜腺。成熟蜜腺的结构由分泌表皮和泌蜜组织构成。分泌表皮单层,细胞壁薄,其上有少量气孔存在,外切向壁角质层薄。泌蜜组织细胞5—6层。泌蜜组织基部具维管束、筛管或导管分子直达泌蜜组织基部。紫云英花蜜腺形成较晚,至露冠期基本成熟。PAS反应结果表明,紫云英花蜜腺是淀粉型蜜腺。蜜腺发育早期即在蜜腺细胞内充满众多的多糖颗粒。从结构和发育过程分析,紫云英花蜜腺的花蜜以分泌表皮层直接泌出为主,气孔泌出是辅助途径。     

荆条花蜜腺发育解剖学研究

荆条（Ｖｉｔｅｘ ｃｈｉｎｅｎｓｉｓ Ｍｉｌｌ．）花蜜腺属于淀粉型子房蜜腺,呈圆筒状环绕于子房的基部。蜜腺外观上无特殊结构,表面有。由分泌表皮和泌蜜组织组成,包括分泌表皮、气孔器、泌蜜薄壁组织和维管束。密腺和子房壁起源相同。花蕾膨大期,泌蜜组织细胞中产生大液泡;露冠期,泌蜜组织中形成维管束;花蕾初放期,分泌表皮细胞分化形成气孔器,无气孔下室,淀粉粒的积累在此期达到高峰;盛花期,蜜腺中已无淀粉粒,密     

荔枝花蜜分泌规律及可溶性糖组分和含量的分析

为了解荔枝(Litchi chinensis)花蜜的分泌规律和主要组分,对‘糯米糍’、‘桂味’和‘怀枝’3个主栽品种雄花和雌花的花蜜分泌模式进行研究,并测定花蜜中可溶性糖的组分和含量。结果表明,采样期间果园阴天和晴天气温差异不明显,但阴天的相对空气湿度显著高于晴天。总体上阴天的荔枝花蜜分泌量高于晴天,雌花的花蜜分泌量高于雄花,‘桂味’和‘糯米糍’的花蜜分泌量均高于‘怀枝’。晴天花蜜中的可溶性固形物含量高于阴天的,且在雌花中表现尤为明显。‘怀枝’花蜜中的可溶性固形物含量最高,可达37.7%,‘桂味’其次,‘糯米糍’最少(17.7%)。利用高效液相色谱检测,荔枝花蜜中主要可溶性糖组分为葡萄糖、果糖和蔗糖,以葡萄糖含量最高。晴天时‘怀枝’雌花花蜜中可溶性糖含量达450.36μg m L–1,显著高于另外两个品种。这为荔枝栽培和花蜜生产提供科学依据。     

小花糖芥花蜜腺的解剖学研究

小花糖芥（Erysimum cheiranthoides L.)花蜜腺位于雄蕊部花托上,仅有2枚侧蜜腺,属十字花科侧蜜腺类型中的侧半环亚型,其2枚密腺均由分泌表皮,产蜜组织和维管束组成。分泌表皮上有变态气孔器,产蜜组织中有维管束分布,属较进化的十字花科花蜜腺亚型类型。蜜腺原基是在花的各部分原基基本分化完成后,由花托表面及雄蕊基部区域的1－2层细胞,经反分化形成,在蜜腺发育过程中,蜜腺组织中的液泡和多糖物质都发生了有规律的变化,其原蜜汁在产蜜组织中加工合成,最后由表皮细胞和变态气孔泌出。     

多叶斑叶兰花蜜特征和分泌规律及其对昆虫访花的影响

为探讨多叶斑叶兰(Goodyera foliosa)花蜜体积和成分的变异性,及其对传粉昆虫的影响,采用毛细管法、折光仪和高效液相-蒸发光法对一天内不同时间段单花花蜜体积、总糖浓度和可溶性糖成分及含量进行检测,用摄像机对其传粉昆虫访花行为进行观察。结果表明,单花花蜜体积在10:00达到最大[(7.19±2.29)μL, n=10],糖浓度在16:00达到最大[(25.85±1.83)%,n=10]。花蜜中的主要可溶性糖为果糖和蔗糖,果糖在上午10:00含量达到最高(78.310 mg/g);蔗糖在下午16:00含量达到最高(247.600 mg/g)。中华蜜蜂(Apis cerana)访花时间为每天9:00-15:00,访花高峰期在10:00-14:00;橘尾熊蜂(Bombus friseanus)访花时间为每天8:00-16:00,访花高峰期在10:00-12:00和16:00-18:00。因此,这两种传粉昆虫访花频率与多叶斑叶兰单花花蜜体积及糖浓度的变化有一定的相关性,它们更倾向于访问较高花蜜体积及糖浓度的花朵。多叶斑叶兰花蜜成分中蔗糖占优势,能有效吸引各种蜂类、蝶类和蚁类访花,且访问频率较高,中华蜜蜂和橘尾熊蜂能携带其花粉块,是主要的有效传粉昆虫。花形态和访花昆虫的体型大小的匹配,决定了是否成为有效传粉昆虫。     

海拔和坡向对色季拉山蒲公英总黄酮及糖分含量的影响

【目的】蒲公英是西藏最常见的药食两用植物,研究其植株内主要药理活性成分黄酮类、多糖以及其他糖分含量在种间差异以及随着坡向和海拔梯度的变化特征,对其高效开发利用具有重要的指导意义。【方法】以毛柄蒲公英、大头蒲公英、锡金蒲公英、灰果蒲公英、反苞蒲公英和角苞蒲公英不同坡向和海拔样地的全草样本为研究材料,分别对植株中的总黄酮和几种糖分含量进行了测定和分析。【结果】（1）总黄酮含量在毛柄蒲公英西坡3 900 m样本中最高（80.96 mg/g）,而锡金蒲公英东坡2 300 m样本含量（29.08 mg/g）最低,并显著低于其他样本（P<0.05）。（2）总糖含量在反苞蒲公英东坡2 000 m样本中达440.55 mg/g,显著高于其他样本;而锡金蒲公英西坡4 200 m样本仅63 mg/g,显著低于其他样本。（3）所有样本中还原性糖含量最高为61.1 mg/g,最低为35.98 mg/g,但不同种质和不同海拔高度之间的差距不如总糖含量明显。（4）多糖含量在反苞蒲公英东坡2 000 m和锡金蒲公英西坡3 000 m样本高达320 mg/g以上,而锡金蒲公英西坡4 200 m和3 900 m以及毛柄蒲公英西坡3 900 m样本含量不足70 mg/g,并与其他样本差异显著。【结论】西藏蒲公英中黄酮和多糖含量较高,并在不同种质之间差异明显;黄酮和多糖含量随海拔或坡向呈相反变化趋势,而多糖和总糖含量则有相似的变化规律;高海拔和西坡向可能有利于黄酮积累,低海拔和东坡向可能有利于多糖积累。     

施肥对大棚甜椒品质的影响

对塑料大棚栽培的甜椒进行滴灌施肥,研究不同用量的氮磷钾肥料对甜椒品质的影响,结果表明,侧枝是甜椒硝态氮的敏感反应部位,且含量最高,叶片次之,果实最少,高量施肥对甜椒果实的硝态氮与可溶性糖含量没有产生不良影响,果实是甜椒糖分的主要贮存器官,其可溶性总糖含量在50%-55%范围内,高于叶片和侧枝,施肥量减少,果实中肌醇和蔗糖的含量增加,葡萄糖与果糖是甜椒果实主要的可溶性糖类,高量施肥削弱叶片的C素代谢作用,表现为抑制同化物淀粉在叶片的积累,粗淀粉在果实中的含量最高,叶片脂类含量均超过侧枝和果实3-4倍以上,可能是由于叶片中叶绿素含量高所致。     

氟化氢熏气对金华佛手叶片、花和果实中有机营养物含量的影响

HF人工熏气后佛手叶中光合速率及叶绿素、可溶性总糖、蔗糖、核酸、蛋白质含量均下降,淀粉及果糖含量上升;花中果糖、蔗糖、可溶性总糖及核酸含量均下降;果中的果糖、蔗糖及可溶性糖含量均上升,蛋白质含量下降.     

芭蕉科花蜜腺形态比较: 兼论其与传粉者的关系

对狭义芭蕉科3个属的代表性种芭蕉(Musa basjoo)、象腿蕉(Ensete glaucum)和地涌金莲(Musella lasiocarpa)的花蜜腺形态进行了比较研究。结果表明它们的蜜腺属于隔膜蜜腺。雌花的蜜腺着生于子房的上部, 胚珠的上方; 雄花蜜腺占据了整个败育子房的位置。蜜腺结构由许多腔道组成, 这些腔道在横切面上呈现出复杂的发散式迷宫状结构。这3种植物花蜜腺的栅栏状表皮细胞、维管束和蜜腺开口方式相似, 而从纵切面和横切面上观察其结构存在一些差异。PAS反应显示象腿蕉泌蜜组织中淀粉粒含量高于其他两个种; 芭蕉和象腿蕉的蜜腺腔里有许多纤维状物质存在。3种植物的传粉综合征多样化, 花序和花的特征(如花序下垂或直立、苞片的颜色、泌蜜量和泌蜜时间等)和传粉样式之间有密切关系。它们的蜜腺结构和传粉者行为之间没有明显的相关性, 但是胶质或水质的花蜜对传粉者的取食方式有一定影响。     

Micro-organisms behind the pollination scenes: microbial imprint on floral nectar sugar variation in a tropical plant community

Background and Aims

Variation in the composition of floral nectar reflects intrinsic plant characteristics as well as the action of extrinsic factors. Micro-organisms, particularly yeasts, represent one extrinsic factor that inhabit the nectar of animal-pollinated flowers worldwide. In this study a ‘microbial imprint hypothesis’ is formulated and tested, in which it is proposed that natural community-wide variation in nectar sugar composition will partly depend on the presence of yeasts in flowers.

Methods

Occurrence and density of yeasts were studied microscopically in single-flower nectar samples of 22 animal-pollinated species from coastal xeric and sub-humid tropical habitats of the Yucatán Peninsula, Mexico. Nectar sugar concentration and composition were concurrently determined on the same samples using high-performance liquid chromatography (HPLC) methods.

Key Results

Microscopical examination of nectar samples revealed the presence of yeasts in nearly all plant species (21 out of 22 species) and in about half of the samples examined (51·8 % of total, all species combined). Plant species and individuals differed significantly in nectar sugar concentration and composition, and also in the incidence of nectar yeasts. After statistically controlling for differences between plant species and individuals, nectar yeasts still accounted for a significant fraction of community-wide variance in all nectar sugar parameters considered. Significant yeast × species interactions on sugar parameters revealed that plant species differed in the nectar sugar correlates of variation in yeast incidence.

Conclusions

The results support the hypothesis that nectar yeasts impose a detectable imprint on community-wide variation in nectar sugar composition and concentration. Since nectar sugar features influence pollinator attraction and plant reproduction, future nectar studies should control for yeast presence and examine the extent to which microbial signatures on nectar characteristics ultimately have some influence on pollination services in plant communities.     

长白山针阔混交林紫椴的泌蜜量

紫椴是东北东部地区原始针阔混交林中优势种或共优种之一,是优质的用材树种,更是重要的蜜源植物。本文研究长白山地区紫椴从单株到种群(林分)的泌蜜量,建立单株泌蜜量回归模型,并估计林分尺度泌蜜量,分析紫椴泌蜜量与胸高断面积以及材积或蓄积之间的关系。结果表明: 紫椴单花开花时间为6～8 d,泌蜜时间为5 d,平均每朵花总泌蜜量为8.58 mg。花蜜的糖浓度在一天中有变化,中午高于早晨和傍晚,平均糖浓度为37.7%。样地紫椴的平均胸径为40 cm,单株开花量为18万个,泌蜜量为1.56 kg(或纯糖0.588 kg)。每公顷紫椴的泌蜜量为79～147 kg(或0.0686～0.1285 m³,纯糖29.78～55.42 kg)。林分泌蜜量与总断面积以及蓄积量密切相关,可以利用森林资源调查数据估算紫椴泌蜜量。     

Removal Effects on Nectar Production in Bat‐pollinated Flowers of the Brazilian Cerrado

We tested the removal effect on nectar production in four bat‐pollinated cerrado flowers. We compared the amount of nectar after 7–12 removals with the accumulated nectar in non‐manipulated flowers after 12 h. In all, but one species, removals increased volume by 1.5–4.6 times and sugar content by 1.6–4 times, which may affect flower visitation by bats, pollen flow, and reproduction. Abstract in Portuguese is available in the online version of this article.     

An examination of nectar production in 34 species of Dendrobium indicates that deceptive pollination in the orchids is not popular

Nectar, the most common floral reward, is generally used to determine whether an orchid species involves deceptive pollination. Estimates of the deceptive pollination systems with nectarless flowers have ranged from one quarter to one third of the nearly 30 000 species of orchids. These estimates, however, are biased towards temperate-zone, usually terrestrial, orchids. Here we investigated nectar production and property in 34 epiphytic orchid species of the Southeast Asian genus Dendrobium. Twenty-one species were observed producing nectar. The amount and sugar concentration (in bagged flowers) of 12 species varied from 0.45 to 2.78 μL and from 8.1% to 31.1%. The nectar was sucrose-dominant, typical of bee-pollinated flowers. Reconstruction of phylogenetic relationship indicated that transition of nectar secretion occurred in the genus. Spur length was positively correlated with flower size but species with relatively long spurs tended to produce small volume of nectar. Nectar production was strikingly variable among and within individuals in some species, suggesting that a vital measurement of bagged and fresh flowers is needed. Given that the quantitative measurement of nectar or floral reward in orchid species remains scarce, an estimate of deceptive pollination systems awaits further survey in diverse genera.     

Variability of nectar production and composition in Linaria vulgaris (L.) Mill. (Scrophulariaceae)

 We studied nectar characteristics during the long flowering period (late June to end of November) in two populations of Linaria vulgaris (L.) Mill. spontaneously growing in the Botanical Gardens of Siena University (Tuscany, central Italy). The two populations were close to each other but they differed in blooming period. Plants of population 1 sprouted in May and flowered from the end of June to the end of September. Population 2 sprouted at the end of August and flowered from September to the end of November. Differences in nectar production and composition were found between and within populations. Flowers of population 1 produced a very small amount of nectar (not collectable) that remained on the nectary surface. The quantity of nectar increased in late September, when each flower produced 2–3 μl of nectar that flowed into the spur. Total sugar concentration was 175.8 mg/ml in young flowers. Flowers of population 2 produced 5–8 μl of nectar with a total sugar concentration of 200.9 mg/ml in the young stage. In bagged senescent flowers nectar volume decreased in both populations and nectar sugar concentration decreased down to 11.6 mg/ml in population 2 and increased up to 289.6 mg/ml in population 1. For both populations, the decrease in nectar volume in bagged flowers may have been due to water loss by evaporation. In population 2, the decrease in sugar concentration may have been due to nectar reabsorption that was never observed in population 1. Nectar variability is discussed in relation to insect visits and seed set. Received August 14, 2002; accepted December 17, 2002 Published online: June 2, 2003     

Geographical and Seasonal Variation in the Richness of Ant-Plant Interactions in México1

The richness and seasonal variation of ant-plant interactions were compared in four habitats in México: lowland tropical dry forest (La Mancha, Veracruz), coastal sand dune matorral (San Benito, Yucatán), semiarid highland vegetation (Zapotitlán, Puebla), and lower montane humid forest (Xalapa, Veracruz). The effects of temperature and precipitation on the seasonal distribution of the number of ant-plant interactions differed among habitats. The general linear models fitted to the ant-plant interaction curves explained 78.8 percent of the variation for La Mancha, 80.1 percent for Zapotitlán, 18 percent for San Benito, and 29.5 percent for Xalapa. Even though rainfall is low in Zapotitlán and San Benito, minimum temperature was the most important factor accounting for the seasonal distribution and low number of interactions. At La Mancha, with milder minimum temperatures and higher water availability, temperature alone did not account for the seasonal distribution and number of interactions, whereas the effect of the precipitation × temperature interaction was highly significant. Xalapa exhibits the lowest temperatures and the highest precipitation, but the role of these factors was only marginal. We suggest that the vegetation at Xalapa, a mixture of tropical and temperate floristic elements, constrains ant-plant interactions due to a limited presence of nectaries. Also, ants are less abundant in cool and relatively aseasonal habitats. The other habitats have tropical floristic elements that are abundant and frequently have nectar-producing structures. We report considerable variation among habitats in the number and seasonal distribution of ant-plant interactions, and suggest that it is due to the effect of variation in environmental parameters, the richness of plants with nectaries in the vegetation, and habitat heterogeneity.     

Bees get a head start on honey production

Nectar concentration is assumed to remain constant during transport by honeybees between flowers and hive. We sampled crop contents of nectar foragers on Aloe greatheadii var. davyana, a major winter bee plant in South Africa. The nectar is dilute (approx. 20% w/w), but the crop contents of bees captured on flowers are significantly more concentrated. In returning foragers, the concentration increases further to 38–40%, accompanied by a volume decrease. The doubling of sugar concentration suggests that nectar is regurgitated onto the tongue and evaporated during foraging and on the return flight. Processing of the dilute nectar into honey thus begins early, aided by low ambient humidities. This has implications for honeybee thermoregulation, water balance and energetics during foraging, and for the communication of nectar quality to recruits.     

Jack of all nectars, master of most: DNA methylation and the epigenetic basis of niche width in a flower-living yeast

In addition to genetic differences between individuals as a result of nucleotide sequence variation, epigenetic changes that occur as a result of DNA methylation may also contribute to population niche width by enhancing phenotypic plasticity, although this intriguing possibility remains essentially untested. Using the nectar‐living yeast Metschnikowia reukaufii as study subject, we examine the hypothesis that changes in genome‐wide DNA methylation patterns underlie the ability of this fugitive species to exploit a broad resource range in its heterogeneous and patchy environment. Data on floral nectar characteristics and their use by M. reukaufii in the wild were combined with laboratory experiments and methylation‐sensitive amplified polymorphism (MSAP) analyses designed to detect epigenetic responses of single genotypes to variations in sugar environment that mimicked those occurring naturally in nectar. M. reukaufii exploited a broad range of resources, occurring in nectar of 48% of species and 52% of families surveyed, and its host plants exhibited broad intra‐ and interspecific variation in sugar‐related nectar features. Under experimental conditions, sugar composition, sugar concentration and their interaction significantly influenced the mean probability of MSAP markers experiencing a transition from unmethylated to methylated state. Alterations in methylation status were not random but predictably associated with certain markers. The methylation inhibitor 5‐azacytidine (5‐AzaC) had strong inhibitory effects on M. reukaufii proliferation in sugar‐containing media, and a direct relationship existed across sugar × concentration experimental levels linking inhibitory effect of 5‐AzaC and mean per‐marker probability of genome‐wide methylation. Environmentally induced DNA methylation polymorphisms allowed genotypes to grow successfully in extreme sugar environments, and the broad population niche width of M. reukaufii was largely made possible by epigenetic changes enabling genotype plasticity in resource use.