Flowers and Beetles in the South American Tropics

Examples of beetle pollination in the South American tropics are given. The case histories refer to representatives of the families Cyclanthaceae, Annonaceae, and Araceae. In most cases the cantharophilous syndrome does not seem to be the result of coevolution but of a one-sided adaptation of flowers to the behavior, necessities, and sense-capacities of beetle species. It is emphasized that cantharophily may not necessarily be an indication of ancientness of a flower/insect relationship. Besides primitive angiosperms, there are derived and modern groups which, in their pollination, are specialized for beetles. Carludovica palmata (Cyclanthaceae) is pollinated by small curculionids which are attracted by odors in the early morning hours. Annona coriacea (Annonaceae) and Philodendron selloum (Araceae) are pollinated by large dynastid scarab beetles in the evening hours. In all three species thermogenesis occurs. Although belonging to widely separate systematic groups, Annona flowers and Philodendron inflorescences have a similar pollination biology, which indicates that their adaptations to beetles are the result of convergent evolutionary developments.     

A semi-lunar periodicity of neurotransmitter-like substances from plants

Cardioacceleratory activity was found in ethanolic extracts of the leaves of Coleus blumei (Benth, var. verschaffeltii), Phaseolus vulgaris L., and Philodendron (Schott) sagittifolium. The cardioacceleratory activity fluctuated considerably from day to day and from sample to sample but displayed a consistent tendency to drop to very low levels shortly after full moon and new moon. The tendency to fall to low levels at semi-lunar intervals is compared with similar findings in cockroach, mouse and human blood and complementary findings in cockroach nervous tissue.     

希望蔓绿绒离体快繁技术研究

以新引进的希望蔓绿绒茎段为材料,利用植物组织培养方法进行快繁研究。结果表明,MS + 6-BA 2 mg/L + NAA0.1 mg/L是较为理想的继代增殖培养基,最佳生根培养基是MS + IBA 0.5 mg/L。     

蔓绿绒属观赏植物的组织培养快速繁殖技术

利用7个蔓绿绒属观赏植物品种进行了该属植物的组织培养和快速繁殖技术规律的探讨。不同品种的组织培养表现有较大的差异。该属植物一般需经高浓度(2～8mg／L)6-BA处理,才能建立其快速繁殖无性系,2mg／L6-BA适合快速繁殖系的增殖,繁殖倍数达4～5倍。1／2MS NAA0．5mg／L培养基适合该属植物的组培苗生根。‘绿帝王’和‘金帝王’幼花序在MS NAA0．5mg／L 6．BA 5mg／L培养上较有利于胚状体的诱导。     

水培对羽裂蔓绿绒解剖结构的影响

采用石蜡切片法,对天南星科植物羽裂蔓绿绒(Philodendron pitfieri Engl.)水培和土培根的解剖特征进行观察,探讨蔓绿绒适应水生环境的形态学特点,并比较了水培根与土培根的形态解剖学差异.结果表明:水培后根冠不明显,淀粉体较少,多糖类物质较少而土培根根冠体积较大,淀粉体较多,多糖类物质多,土培根PAS反应强烈;水培根表皮厚度比土培根小,水培根根毛少或退化消失;水培根皮层薄壁组织发达,细胞大型,壁薄,细胞间隙中含有溶生性通气组织,土培根皮层未见通气组织.     

Quantitative developmental analysis of homeotic changes in the inflorescence of Philodendron (Araceae)

Background and Aims: The inflorescence of Philodendron constitutes an interestingmorphological model to analyse the phenomenon of homeosis quantitativelyat the floral level. The specific goals of this study were (1)to characterize and quantify the range of homeotic transformationin Philodendron billietiae, and (2) to test the hypothesis thatthe nature of flowers surrounding atypical bisexual flowers(ABFs) channel the morphological potentialities of atypicalbisexual flowers. Methods: Inflorescences of P. billietiae at different stages of developmentwere observed using SEM. The number of appendices in male, femaleand sterile flowers were counted on 11 young inflorescences(5–6 flowers per inflorescence). The number of staminodesand carpels on ABFs were counted on 19 inflorescences (n = 143).These data were used for regression and ANOVA analyses. Results: There was an average of 4·1 stamens per male flower,9·8 carpels per female flower and 6·8 staminodesper sterile male flower. There was an average of 7·3floral appendices per atypical flower. Staminodes and carpelsare inserted on the same whorl in ABFs. A negative exponentialrelationship was found between the average number of staminodesand the number of carpels in ABFs. If only the ABFs consistingof less than six carpels are considered, there is a linear relationshipbetween the number of carpels and the average number of staminodes.The value of the slope of the regression equation indicatesthat on average, in P. billietiae, 1·36 carpels are replacedby one staminode. Conclusions: In P. billietiae, the number of appendages in female flowersimposes a constraint on the maximum total number of appendages(carpels and staminodes) that can develop on ABFs. The quantitativeanalyses indicate that the average number of different typesof floral appendages on an ABF and the number of organs involvedin a homeotic transformation are two independent phenomena.     

圆叶蔓绿绒快速繁殖条件的优化

以带侧芽茎段为外植体,对圆叶蔓绿绒组织培养及快速繁殖的研究表明,不同生长调节剂组合对圆叶蔓绿绒的离体形态发育及增殖均有重要影响。其中适合侧芽生长和不定芽分化的组合为BA 3.0mg/L+ IAA 0.5mg/L。采用BA 0.8mg/L+ KT 0.8mg/L+IAA 0.05mg/L的组合可在4周内可获得7.0的增殖系数。培养基中添加适量活性炭对生根有促进作用。适宜量为1.0g/L。     

低温及光照对红苞蔓绿绒幼苗膜脂过氧化的影响

本文研究低温和光照条件对红苞蔓绿绒幼苗膜脂过氧化作用的影响。目测结果表明,红苞蔓绿绒幼苗叶片受低温伤害程度与对照差异不明显,且各处理间差异不显著。各处理的丙二醛含量基本上高于对照,细胞膜透性、过氧化氢酶和过氧化物酶活性均高于对照,说明红苞蔓绿绒幼苗具有较高的抗低温能力,膜脂过氧化水平随低温胁迫强度的增强而增大,过氧化氢酶和过氧化物酶活性与丙二醛含量成正相关。5℃时,在光照条件下幼苗的细胞膜透性、丙二醛含量、过氧化氢酶和过氧化物酶活性均高于暗处理;但10℃时结果却相反。     

Respiration of thermogenic inflorescences of Philodendron melinonii: natural pattern and responses to experimental temperatures

The patterns of temperature and respiratory changes in the protogynousinflorescences of Philodendron melinonii (Araceae) were studiedin the field in French Guiana. These are the first respiratorymeasurements from a member of the large subgenus Philodendron,a group previously thought to lack thermoregulatory inflorescences,in contrast to thermoregulatory Philodendron species of thesubgenus Meconostigma. Heating by the male and sterile maleflorets was strong on the first evening of anthesis when beetlesare attracted and the female florets are receptive. Heat productionof the inflorescence peaked at 0.9 W and spadix temperaturereached 39.5 °C, a level somewhat independent of ambienttemperature. Thermogenesis continued throughout the night andthe next day, but at a lower level, and floral temperaturesfell. On the second evening, when pollen was shed, there wasa small elevation in respiration and spadix temperature. Responsesof cut spadix sections to experimental step changes in ambienttemperature resulted in a prompt response in floral temperatureand respiration rate in the direction of the change and thena much slower regulatory adjustment in the opposite direction.These responses are consistent with an immediate van 't Hoffeffect, followed by up- or down-regulation of thermogenesis.However, the responses required several hours. It is concludedthat the male floret tissues possess the same thermoregulatorymechanism of more precise thermoregulatory species, but a combinationof small spadix size (that favours heat loss), moderate thermogeniccapacity (that limits heating rate), and slow reaction time(that causes long lags between temperature change and the regulatoryresponse) result in poor thermoregulatory performance duringthe second day. Key words: Arum lily, heat production, inflorescence, Philodendron, protogynous, regulation, respiration, thermogenesis, van 't Hoff effect Received 29 December 2007; Revised 23 January 2008 Accepted 24 January 2008