Floral surveys on Gomphonemaceae and Cymbellaceae (Bacillariophyta) from the headwaters of the Yangtze River, Qinghai, China

Gomphonemaceae and Cymbellaceae from the headwaters of the Yangtze River, Qinghai Province, China, comprised 84 taxa belonging to four genera. The dominant species were Gomphonema kaznakowi Mer., G. hedini Hust., G. olivaceum (Lyngbye) Kutz., Cymbella cistula (Ehr.) Kirchn. var. cistula and C. minuta Hilse ex Rabh. var. minuta. Some arctic and alpine forms also occurred, and the following taxa were unique to this region: C. cistula var. asiatica Mer., C. cistula var. capitata Grun., C. yabe Skvortzow var. punctata Li and Shi, G. olivaceum (Lyngbye) Kutzing var. brevistriatum Li and Shi and G. staurophorum (Pant.) Cleve-Euler var. oblongum Li and Shi. Different morphological forms of G. kaznakowi Mer. may be related to the upheaval of the plateau. Species diversity of the diatoms appears to be related not only to macro-environment (e.g., geographic zonation) but also to microhabitat and microclimate.

Floral Organogenesis and Development of two Taxa in Tribe Hyoscyameae (Solanaceae)-Przewalskia tanguitca and Hyoscyamus niger

Floral organogenesis and development of Przeivalskia langutica Maxim, endemic to China and Hyoscyamus niger L. , which belong to the tribe Hyoscyameae (Solanaceae), were studied using scanning electron microscope. They have three common characters of floral organ initiation and development: 1) initia-tion of the floral organs in the two species follows Hofmeister's rule; 2) the mode of corolla tube development belongs to the "late sympetaly" type; 3) primordia of the floral appendages initiated in a pentameroua pattern and acropetal order. But initiation of the calyx-lobe primordia showed different modes in these two species. The calyx-lobe primordia of H, niger have simultaneously whorled initiation, while those of P, tangulica have helical initiation, but the five calyx-lobe primordia form a ring after all five calyx-lobe primordia occur. The systematic significance of the present results in the genera Hyoscyamus and Przeivalskia is discussed in this paper.

Interannual fluctuations in floral longevity, pollinator visitation and pollination limitation of an alpine plant (Gentiana straminea Maxim., Gentianaceae) at two altitudes in the Qinghai-Tibetan Plateau

Prolonged floral longevity and bumblebees as dominate pollinators in alpine ecosystem have been suggested to overcome pollination limitation of alpine plants arising from the decrease of pollinator activity with increasing altitude. However, this conclusion has never been examined in the Qinghai-Tibetan Plateau (QTP), the highest and largest plateau in the world. In this study, we intended to test year-to-year correlations between floral longevity, visiting frequency and pollen limitation of this species between two populations (at 3200 m and 4000 m) of Gentiana straminea in this plateau. Pollinator exclusion elongated both male and female phases greatly at both sites, and durations of both male and female phases in natural condition varied greatly over three years. The visiting frequency of bumblebees varied greatly at the higher altitude, but seemed to be stable at the lower altitude. Seed production was pollination limited in both populations in most studied years. The floral durations, pollinator frequency and pollination limitation showed no significant and consistent variations with the increase of altitude. The previous hypothesis that the prolonged floral longevity of alpine plants can compensate for low levels of pollinator visitation therefore could not be confirmed, and our results further suggested that in the QTP platform, the altitude shows no consistent effect on the reproductive performance of this species, despite that the fluctuation of visit frequency intensified at the higher altitude.

Floral closure in response to temperature and pollination in Gentiana straminea Maxim. (Gentianaceae), an alpine perennial in the Qinghai-Tibetan Plateau

Floral closure may be induced by pollination and various other factors, but is rarely studied comprehensively. Different kinds of floral closure should have various effects on reproductive fitness of plants. Two contrasting types of floral closure were observed in the flowers of Gentiana straminea Maxim. in the eastern Qinghai-Tibetan Plateau. The first type occurred prior to pollination during both gender phases, in response mainly to decreasing air temperatures. Flowers closed when decreasing temperatures approached 20 degrees C and subsequently began to reopen the following day during mid-morning when air temperatures warmed to approximately 13-15 degrees C. This kind of floral closure can protect pollen grains on either stamens or stigmas, increasing fitness of both male and female. Following pollination, permanent floral closure occurred, although there was a delay between the dates of pollination and permanent closure, during which flowers continued to show temporary closure in response to low temperature episodes. The time required for permanent, pollination-induced closure varied according to the age of the gender phase, including a prolonged time before closure if pollination occurred early in the female phase. The retaining of permanent closed flowers increased both approaching (to inflorescences) and visiting (to unpollinated flowers) frequencies of individual plants when with fewer open flowers and the persisting corolla is further beneficial for seed sets of these pollinated flowers. Thus, two separate types of floral closure, one in response to environmental cues and the other in response to the age of each gender stage, appeared to have a strong influence on reproductive fitness in this species. These results revealed a different adaptive strategy of alpine plants in the sexual reproduction assurance in addition to the well-known elevated floral longevity, dominant role of more effective pollinators and increased reproduction allocation in the arid habitats.

Floral organogenesis and development of two taxa of the Solanaceae - Anisodus tanguticus and Atropa belladonna

Floral organogenesis and development of two Solanaceae species, Anisodus tanguticus and Atropa belladonna, were studied by using scanning electron microscopy (SEM) as part of a project on systematics and evolution in the tribe Hyoscyameae. These two species share the following common characters of floral organ initiation and development: (1) initiation of the floral organs in the two species follows Hofmeister's rule; (2) the mode of corolla tube development belongs to the "late sympetaly" type, namely, petals are initiated separately and later become joined by fusion of their basal meristem, then rise together and form a corolla tube; (3) primordia of the floral appendages are initiated in a pentamerous pattern and acropetal order: sepals are initiated first, followed by the petals and stamens, and finally the carpels. The whorl of five stamen primordia forms almost simultaneously and originates opposite the sepal primordia, but initiation of the sepal primordia shows different modes in the two species. The sepal primordia of Anisodus tanguticus have simultaneously whorled initiation, while those of Atropa belladonna have helical initiation. The systematic significance of the present results in the genera Anisodus and Atropa is discussed in this paper.

Biologia e manejo de mosca minadora no meloeiro.

2009

Mosca-negra-dos-citros Aleurocanthus woglumi Ashby (Hemiptera: Aleyrodidae) em culturas de citros e de mangueira no estado de São Paulo e observações de sua biologia e controle.

Resumo: O principal objetivo deste trabalho foi avaliar a infestação da mosca-negra-dos-citros, A. woglumi, observada em janeiro de 2008, em pomar comercial de laranja Pêra-Rio porta enxerto de Limão-Cravo, de nove anos de idade, e em árvo- res isoladas de mangueira variedades Haden e Palmer, de sete a oito anos de idade, no município de Artur Nogueira, estado de São Paulo. Outros objetivos foram relatar a sua biologia, os níveis de danos e o controle biológico dessa praga.

Resultados de pesquisa da Embrapa Soja - 2000: ecofisiologia e biologia molecular.

Maximização do aproveitamento das disponibilidades climáticas pela soja; Bases agronômicas e fisiológicas das respostas da soja à disponibilidade hídrica (04.2000.331-01); Bases agronômicas e fisiológicas das respostas da soja às condições térmicas e fotoperiódicas (04.2000.331-02); Identificação, clonagem e sequenciamento de genes diferencialmente expressos em resposta às variações climáticas em soja (04.2000.331-03); Manejo dos recursos disponíveis do ambiente para produção de soja (04.2000.331-04); Estratégias para amenizar impactos decorrentes das adversidades climáticas (04.2000.331-05); Modelos de simulação do desenvolvimento da cultura da soja em resposta às variáveis do ambiente (04.2000.331-06); Genética aplicada ao melhoramento da soja; Identificação de marcadores moleculares ligados a genes de resistência a doenças (04.2000.322-01); Variabilidade genética de patógenos de soja (04.2000.322-02); Caracterização do germoplasma ativo de soja com marcadores moleculares tipo AFLP e micros-satélites (04.2000.322-03); Genética quantitativa aplicada ao melhoramento da soja: diversidade genética e resistência a doenças (04.2000.322-04); Desenvolvimento de soja transgênica com genes de interesse ao melhoramento (04.2000.322-05); Zoneamento agroclimático das principais culturas de grãos do Brasil; Caracterização da aptidão climática de regiões para o cultivo de soja no Brasil (01.2000.051-03).

Ocorrência do pulgão-do-milho Rhopalosiphum maidis (Fitch, 1856): identificação, biologia e danos.

2006

Caracterização das fases de desenvolvimento e aspectos da biologia do percevejo barriga-verde Dichelops melacanthus (Dallas, 1851).

2007

Podridão da uva madura ou podridão de Glomerella: biologia, epidemiologia e controle.

2004

Identificação varietal e genotipagem: serviços oferecidos pelo Laboratório de Biologia Molecular da Embrapa Uva e Vinho.

2005

A podridão floral dos citros no Estado do Amazonas.

Identificacao e combate a podridao floral dos citros no estado do Amazonas.

Alguns aspectos sobre a biologia, comportamento, infestacao e perdas causadas pela broca-do-fruto (Conotrachelus sp.) do cupuacuzeiro (Theobroma grandiflorum Schum.), em Manaus-AM.

Estudo sobre a biologia, comportamento, intensidade de infestacao e quantificacao das perdas causadas pela broca-do-fruto no cupuacuzeiro para fornecer informacoes e, desse modo, aumentar os conhecimento de como melhorar o manejo dessa praga. O trabalho foi realizado em duas fases: a) campo - coleta semanal dos frutos caidos ao chao, registando o numero de furos na casca e o de larvas no interior do fruto; b) laboratorio - as larvas do ultimo instar foram colocadas dentro de garrafas de plastico de 2l contendo mistura de vermiculita esterilizada por 1h, a 160°C, na proporcao de 2:1. O substrato foi umedecido com agua destilada e as garrafas mantidas a 27°C±2°C, em umidade relativa de 80%±10% e fotoperiodo de 12h:12h, para o desenvolvimento pupal. A regiao mediana dos frutos foi a preferida para a perfuracao de saida das larvas. O numero de larvas foi crescente de fevereiro a abril, epoca de maior producao de frutos. A duracao media para transformacao da larva do ultimo instar para a emergencia dos adultos foi de 65,34 dias, a viabilidade foi de 81,62%, e a raza sexual, 1:1. a intensidade de infestacao foi de 85,0% a 93,33%, com altas perdas na producao.

Biologia e manejo do pulgão Aphis gossypii em meloeiro.

Esta Circular Técnica tem como objetivo auxiliar na correta identificação de A. gossypii e de seus danos no meloeiro, além de fornecer informações básicas para o seu manejo.