Angiosperms

1.A major challenge in evolutionary ecology is to understand how coevolutionary processes shape patterns of interactions between species at community level. Pollination of flowers with long corolla tubes by long-tongued hawkmoths has been invoked as a showcase model of coevolution. Recently, optimal foraging models have predicted that there might be a close association between mouthparts length and the corolla depth of the visited flowers, thus favouring trait convergence and specialisation at community level. 2.Here, we assessed whether hawkmoths more frequently pollinate plants with floral tube lengths similar to their proboscis lengths (morphological match hypothesis) against abundance-based processes (neutral hypothesis) and ecological trait mismatches constraints (forbidden links hypothesis), in structuring hawkmoth-plant mutualistic networks from five communities in four biogeographical regions of South America. 3.We found convergence in morphological traits across the five co...

Volatiles were isolated from the dried inner bark of Tabebuia impetiginosa using steam distillation under reduced pressure followed by continuous liquid-liquid extraction. The extract was analyzed by gas chromatography and gas chromatography-mass spectrometry. The major volatile constituents of T. impetiginosa were 4-methoxybenzaldehyde (52.84 microg/g), 4-methoxyphenol (38.91 microg/g), 5-allyl-1,2,3-trimethoxybenzene (elemicin; 34.15 microg/g), 1-methoxy-4-(1E)-1-propenylbenzene (trans-anethole; 33.75 microg/g), and 4-methoxybenzyl alcohol (30.29 microg/g). The antioxidant activity of the volatiles was evaluated using two different assays. The extract exhibited a potent inhibitory effect on the formation of conjugated diene hydroperoxides (from methyl linoleate) at a concentration of 1000 microg/mL. The extract also inhibited the oxidation of hexanal for 40 days at a level of 5 microg/mL. The antioxidative activity of T. impetiginosa volatiles was comparable with that of the well-known antioxidants, alpha-tocopherol, and butylated hydroxytoluene.

• This study investigated the relationships between root structure and anatomy and whole-plant functioning in herbaceous species.• Fourteen annual and perennial species representative of a Mediterranean old-field succession were grown in monocultures in a common-garden experiment. Whole-plant functioning was assessed by inherent relative growth rate (RGRmax), measured in standardized conditions, and maximum height (Hmax). Root tissue density (TMDr), considered as a major component of root structure, was measured on roots harvested within in-growth cores. Anatomical characteristics were analysed on cross-sectional areas (CSA).• TMDr was correlated positively with Hmax and negatively with RGRmax. Root CSA explained interspecific variation in Hmax but not that in TMDr and RGRmax. Root xylem CSA and xylem proportion in root CSA were positively correlated with TMDr and Hmax and negatively with RGRmax. Mean xylem vessel CSA did not account for variations in TMDr, Hmax and RGRmax.• These results suggested that RGRmax and Hmax are constrained by opposite root structural and anatomical traits, which have potential links with hydraulic conductance, support and longevity.This study investigated the relationships between root structure and anatomy and whole-plant functioning in herbaceous species.Fourteen annual and perennial species representative of a Mediterranean old-field succession were grown in monocultures in a common-garden experiment. Whole-plant functioning was assessed by inherent relative growth rate (RGRmax), measured in standardized conditions, and maximum height (Hmax). Root tissue density (TMDr), considered as a major component of root structure, was measured on roots harvested within in-growth cores. Anatomical characteristics were analysed on cross-sectional areas (CSA).TMDr was correlated positively with Hmax and negatively with RGRmax. Root CSA explained interspecific variation in Hmax but not that in TMDr and RGRmax. Root xylem CSA and xylem proportion in root CSA were positively correlated with TMDr and Hmax and negatively with RGRmax. Mean xylem vessel CSA did not account for variations in TMDr, Hmax and RGRmax.These results suggested that RGRmax and Hmax are constrained by opposite root structural and anatomical traits, which have potential links with hydraulic conductance, support and longevity.

Robinia pseudo-acacia L. (black locust) is a nonindigenous species currently invading the central part of Japanese grasslands. Several allelochemicals were identified and characterized from the leaf tissue. The growth of both radicle and hypocotyl in the tested species (barnyard grass, white clover, lettuce, and Chinese cabbage) was reduced when grown in soil mixed with the leaves of R. pseudo-acacia at various concentrations. Aqueous leaf extracts, when bioassayed, exhibited a significant suppression of radicle growth. Chromatographic separation of an ethanolic extract of R. pseudo-acacia leaves resulted in isolation of three compounds, identified as robinetin (1), myricetin (2), and quercetin (3) by nuclear magnetic resonance and mass spectroscopy. All inhibited root and shoot growth of lettuce. Robinetin, found in a large amount, caused 50% suppression of the root and shoot growth of lettuce at 100 ppm. The presence of these bioactive substances in leaf tissue suggests a potential role for flavonoids in R. pseudo-acacia invasion in introduced habitats.

In order to make an inventory of herbal remedies commonly used in the treatment of diabetes, hypertension and renal diseases in the North centre region of Morocco, 1527 patients (1095 diabetic patients, 274 with renal disorders and 158 with cardiac disorders) and 25 traditional herbal healers were interviewed in four different areas of Fez–Boulemane region. More than 1153 of the total patients interviewed (76%) used regularly medicinal plants to treat diabetes, cardiac and renal diseases. These data showed that phytotherapy has always be practiced in this region. All the persons interviewed have indicated that the reasons of using phytotherapy is that the plant medicines are cheapest (54%) and more efficient (38%) than modern medicine. They also reported that the result of phytotherapy is better (72%). Our survey started at May 1997. About 90 plants were cited (54 plants for diabetes, 11 for cardiac diseases, 19 for hypertension and 33 for renal diseases). The plants reported have been identified and are presented in a table with the vernacular name, useful parts, ecological distribution and medicinal uses. Only 12% of the total patients have a relative knowledge of the toxic plants. The result indicated that nine plants are extremely toxic at high doses and chronic treatment. Fifty nine percent of the interviewers have indicated that they used medicinal plants from the experience of the other.