Tree seedling development in tropical dry abandoned pasture and secondary forest in Costa Rica

Development of planted seedlings of four canopy tree species in recently abandoned pastures (mown and unmown) and in ca. 40-yr old secondary dry forest in Guana-caste National Park, Costa Rica, was studied from July 1989–June 1992. The species were the light-demanding Cedrela odorata and Swietenia macrophylla, and the shade-tolerant Hymenaea courbaril and Manilkara chicle. Seedling mortality was high and primarily correlated with dry season drought. After the first dry season, M. chicle and C. odorata showed < 5 % survival in the pasture and 20 % in the forest, but after 3 yr survival had decreased to 3% in all plots. Survival of S. macrophylla was highest in the mown pasture (45 % after 3 yr) and lowest in the forest (10 %). For H. courbaril, survival was 40–55 % under all three conditions. Growth rates were low, with a height increment of < 15 cm/yr, possibly due to low precipitation in 1990 and 1991. All species grew taller in the pasture than in the forest. Differences in soil depth, texture and drainage appeared to contribute to variation in the results both within and between plots. Herbivory contributed to the lower survival of C. odorata and S. macrophylla in the forest.     

Environmentally-Friendly Pesticidal Activities of Callicarpa and Karomia Essential Oils from Vietnam and Their Microemulsions

There is an ongoing interest to identify alternative pesticidal agents to avoid the chronic problems associated with synthetic pesticides. Essential oils have shown promise as botanical pest control agents. In the present study, the essential oils of four members of the Lamiaceae (Callicarpa candicans, C. erioclona, C. macrophylla, and Karomia fragrans; Vietnamese names: Nàng nàng, Tu châu lông mem, Tu châu lá to and Cà diện, respectively), obtained from wild populations in Vietnam, have been obtained by hydrodistillation and analyzed by gas chromatography-mass spectrometry. The essential oils were formulated into microemulsions and the essential oils and their microemulsions were screened for mosquito larvicidal activity against Aedes aegypti, Aedes albopictus, Culex quinquefasciatus, and for molluscicidal activity against Pomacea canaliculata. Atractylone and (E)-caryophyllene dominated the volatiles of C. candicans (CCEO) and C. erioclona (CEEO), while the major component in C. macrophylla (CMEO) and K. fragrans (KFEO) was (E)-caryophyllene. The essential oils and microemulsions of both C. candicans and C. erioclona exhibited excellent larvicidal activity against all three mosquito species (Ae. aegypti, Ae. albopictus, and Cx. quinquefasciatus) with LC₅₀ values <10 μg/mL. Additionally, the larvicidal activity of the microemulsions were significantly improved compared with their free essential oils, especially for C. candicans and C. erioclona. All four essential oils and their microemulsions showed excellent molluscicidal activity with LC₅₀ <10 μg/mL. In most cases, the essential oils and microemulsions showed greater pesticidal activity against target organisms than the non-target freshwater fish, Oreochromis niloticus. The in silico studies on physicochemical and ADMET properties of the major components in the studied essential oils were also investigated and most of the compounds possessed a favorable ADMET profile. Computational modeling studies of the studied compounds demonstrated a favorable binding interaction with the mosquito odorant-binding protein target and support atractylone, β-selinene, and caryophyllene oxide as potential inhibitors. Based on the observed pesticidal activities of the essential oils and their microemulsions, the Callicarpa species and K. fragrans should be considered for potential cultivation and further exploration as botanical pesticidal agents.     

中药秦艽根内中柱裂分的发育解剖学研究

通过发育解剖学研究表明,秦艽根的初生结构正常,初生木质部四原型。次生生长早期阶段也是正常的,但天以后的次生生长过程中,由于木质部内部分薄壁细胞的分裂,且迅速 化成异常形成层细胞,并与原维管形成层相连,从而形成多个新的形成层环,将木质部柱分为几个子木质部。     

Effects of artificial shade on attack by the mahogany shoot borer, Hypsipyla robusta (Moore)

Abstract

• 1 Swietenia macrophylla King (Meliaceae: Swietenioideae) provides one of the premier timbers of the world. The mahogany shoot borer Hypsipyla robusta Moore (Lepidoptera: Pyralidae) is an economically important pest of S. macrophylla throughout Asia, Africa and the Pacific. No viable method of controlling this pest is known. Previous observations have suggested that the presence of overhead shade may reduce attack by H. robusta, but this has not been investigated experimentally. This research was therefore designed to assess the influence of light availability on shoot‐borer attack on S. macrophylla, by establishing seedlings under three different artificial shade regimes, then using these seedlings to test oviposition preference of adult moths, neonate larval survival and growth and development of shoot borer larvae.
• 2 Oviposition preference of shoot borer moths was tested on leaves from seedlings grown under artificial shade for 63 weeks. A significant difference in choice was recorded between treatments, with 27.4 ± 1.5 eggs laid under high shade and 87.1 ± 1.8 under low shade.
• 3 Neonate larval survival on early flushing leaflets of S. macrophylla did not differ significantly between shade treatments. Larval growth rate, estimated by measuring daily frass width, was significantly higher for those larvae fed on seedlings from the high and medium shade treatments (0.1 mm/day), than the low shade treatment (0.06 mm/day). In laboratory‐reared larvae, the total mass of frass produced was significantly higher in the high shade treatment (0.4 g) than under the low shade treatment (0.2 g).
• 4 Longer tunnel lengths were bored by larvae in plants grown under high shade (12.0 ± 2.4 cm) than under low shade (7.07 ± 1.9 cm). However, pupal mass under low shade was 48% higher than that under the high shade treatment, suggesting that plants grown under high shade were of lower nutritional quality for shoot borer larvae.
• 5 These results indicate that shading of mahogany seedlings may reduce the incidence of shoot borer attack, by influencing both oviposition and larval development. The establishment of mahogany under suitable shade regimes may therefore provide a basis for controlling shoot borer attack using silvicultural approaches.

     

大叶钩藤中非生物碱成分对骨肉瘤细胞增殖的影响

大叶钩藤 (ＵｎｃａｒｉａｍａｃｒｏｐｈｙｌｌａＷａｌｌ.)系茜草科钩藤属植物 ,为常用中药 ,用于治疗头晕目眩、惊痫抽搐、全身麻木等疾病。现已成为治疗高血压方剂中的常用药物[1] 。其化学、药理及应用有较多研究 ,但绝大部分是针对生物碱部分 ,非生物碱部分作为无用成分而极少研究和应用。为了明确其药理作用的物质基础及进一步挖掘其药用潜能 ,作者在对大叶钩藤的非生物碱部分进行系统研究的基础上[2 ] ,对抗肿瘤活性进行研究。1　材料与方法1 1　实验材料实验样品乌索酸 (Ⅰ )、3β 6 β 2 3 三羟基乌索酸 (Ⅲ )、表儿茶素 (Ⅳ )、…     

In Vitro Divisions of Unfertilized Central Cells and Other Embryo Sac Cells in Nicotiana tabacum var macrophylla

The embryo sacs and female cells could be isolated from the unfertilized ovules of Nicotiana tabacum L. var. macrophylla which were treated in a solution containing 1.5 % cellulase R- 1O, 1% macerozyme R-10, 10% mannitol, 10 mmol/L CaCI:, pH 5.8 for 3 h followed by given slight pressure with a micropipette. The central cells could be kept viable for 10 h and the egg cells for 3 h in 10% mannital. Sometimes, the in situ fusion products of egg cell and synergid protoplasts could be obtained and kept viable for at least 5 h. The high concentration (20 mg/L) of 2, 4-D was used in enzyme solution to induce the division of the unfertilized central cells and other megagametophytic cells in subsequent culture. Treatment of 2,4-D together with enzymatic maceration of ovules was proved to be better than its direct treatment of isolated embryo sac or its component cells. Isolated embryo sacs were cultured in microchambers (Millicell-CM PICM 012 50 MILLIPORE) feeded with divided mesophyll protoplasts of Nicotiana rustica L. The medium was KMSp medium supple- mented with 1% glucose, 0.1 mol/L mannitol, 0.1 mol/L sorbitol, 0.25 mol/L sucrose, 1 mg/L BA, 6% to 10% coconut water, and 0.15% low gelling agarose. Division of central cells, antipodal cells and the in situ fusion products of egg cell and synergid protoplasts were induced. The unfertilized central cell was for the first time to be induced in vitro to develop into small cell clusters.     

受精前后烟草卵细胞内玉米素和三类酸性植物激素分布的免疫金电镜观察

用胶体免疫金电镜技术观察了受精前后烟草（Nicotianatabacumvarmacrophylla）卵细胞内玉米素（t－Z）、GA7与GA4、（＋）ABA与IAA分布的变化。受精前卵细胞内有大量t－Z,主要位于细胞核、内质网与线粒体上;与卵细胞相邻的助细胞合点端及中央细胞珠孔端亦有较多t-Z。受精后,合子与宿存助细胞t－z显著减少,正加厚的合子细胞壁中有t－Z分布。未受精卵细胞内GA7与GA4及（＋）ABA减少,IAA更少。合子内GA7与GA4及（＋）ABA略有增加,IAA仍然很少。初步讨论了上述植物激素与受精作用的关系。