Short-Term Storability of Alginate-Encapsulated Persian Violet Microshoots for Germplasm Exchange

Microshoots have been widely used for micropropagation. It may be necessary to store microshoots for a short period of time, for example in germplasm exchange needing transport to other research groups. Here, we investigated the short-term storability of alginate-encapsulated Persian violet (Exacum affine Balf. f. ex Regel) microshoots at 4 °C and 25 °C. After storage, the encapsulated microshoots were sown on basal Murashige and Skoog medium for germination and viability determination using tetrazolium chloride staining. The results showed that one or five microshoots encapsulated with a single alginate layer could be stored at 4 °C for up to 30 days, while the percentages of germination and viability of the microshoots encapsulated with two layers of alginate were greatly reduced upon storage. This is the first report on the storability of alginate-encapsulated multiple microshoots, which could be a more efficient way to encapsulate microshoots used for short-term cold storage.

Transmission of bee-like vibrations in buzz-pollinated plants with different stamen architectures

In buzz-pollinated plants, bees apply thoracic vibrations to the flower, causing pollen release from anthers, often through apical pores. Bees grasp one or more anthers with their mandibles, and vibrations are transmitted to this focal anther(s), adjacent anthers, and the whole flower. Pollen release depends on anther vibration, and thus it should be affected by vibration transmission through flowers with distinct morphologies, as found among buzz-pollinated taxa. We compare vibration transmission between focal and non-focal anthers in four species with contrasting stamen architectures: Cyclamen persicum, Exacum affine, Solanum dulcamara and S. houstonii. We used a mechanical transducer to apply bee-like vibrations to focal anthers, measuring the vibration frequency and displacement amplitude at focal and non-focal anther tips simultaneously using high-speed video analysis (6000 frames per second). In flowers in which anthers are tightly arranged (C. persicum and S. dulcamara), vibrations in focal and non-focal anthers are indistinguishable in both frequency and displacement amplitude. In contrast, flowers with loosely arranged anthers (E. affine) including those with differentiated stamens (heterantherous S. houstonii), show the same frequency but higher displacement amplitude in non-focal anthers compared to focal anthers. We suggest that stamen architecture modulates vibration transmission, potentially affecting pollen release and bee behaviour.

Transmission of vibrations in buzz-pollinated plant species with disparate floral morphologies

In buzz-pollinated plants, bees apply vibrations produced by their thoracic muscles to the flower, causing pollen release from anthers, often through small apical pores. During floral buzzing, bees grasp one or more anthers with their mandibles, and vibrations are transmitted to the focal anther(s), adjacent anthers, and the whole flower. Because pollen release depends on the vibrations experienced by the anther, the transmission of vibrations through flowers with different morphologies may determine patterns of release, affecting both bee foraging and plant fitness. Anther morphology and intra-floral arrangement varies widely among buzz-pollinated plants. Here, we compare the transmission of vibrations among focal and non-focal anthers in four species with contrasting anther morphologies: Cyclamen persicum (Primulaceae), Exacum affine (Gentianaceae), Solanum dulcamara and S. houstonii (Solanaceae). We used a mechanical transducer to apply bee-like artificial vibrations to focal anthers, and simultaneously measured the vibration frequency and displacement amplitude at the tips of focal and non-focal anthers using high-speed video analysis (6,000 frames per second). In flowers in which anthers are tightly held together (C. persicum and S. dulcamara), vibrations in focal and non-focal anthers are indistinguishable in both frequency and displacement amplitude. In contrast, flowers with loosely arranged anthers (E. affine) including those in which stamens are morphologically differentiated within the same flower (heterantherous S. houstonii), show the same frequency but higher displacement amplitude in non-focal anthers compared to focal anthers. Our results suggest that stamen arrangement affects vibration transmission with potential consequences for pollen release and bee behaviour.

Hospedabilidade de plantas ornamentais e medicinais ao nematoide das galhas (Meloidogyne incognita) raça 2

Em razão do aumento na produção de plantas ornamentais e medicinais no estado do Ceará, da importância agrícola do gênero Meloidogyne e da escassez de dados sobre a hospedabilidade desse patógeno nessas espécies, objetivou-se avaliar a susceptibilidade de 30 espécies, sendo 20 ornamentais (Antirrhimum majus), (Gazania ringens), (Carthamus tinctorius), (Bryophyllum cayicinum), (Ceasalpinia pulcherrima), (Thumbergia alata), (Petunia hibryda), (Exacum affine) (Catharanthus roseus), (Opuntia sp.), (Sansevieria trifasciata), (Asparagus densiflorus), (Hibiscus mutabilis-roreus), (Impatiens balsamiana), (Celosia spicata), (Antirrhimum sp.), (Dianthus chinensis), (Zinnia elegans), (Tagetes patula), (Capsicum annuum) e 10 medicinais (Peumus boldus), (Ocimum gratissimum), (Mentha arvensis), (Mentha x Vilosa), (Plectranthus amboinicus), (Ocimum bassilicum), (Rosmarinus officinalis), (Cymbopogon citratus), (Lippia alba), (Cymbopogon winterianus). Realizou-se o ensaio em casa de vegetação, do Setor de Fitossanidade, Departamento de Fitotecnia, da Universidade Federal do Ceará. A inoculação foi realizada com 4.000 ovos/J2 por vaso. A avaliação das plantas deu-se aos 60 dias após a inoculação. Avaliou-se a reação das plantas, mensurando-se: número de galhas e de ovos, índice de massa de ovos, fator de reprodução e redução do fator de reprodução. A partir dos resultados, classificou-se a reação das plantas ao nematoide por meio de cinco critérios. Verificou-se que das plantas ornamentais apenas a espécie T. patula não apresentou galhas em suas raízes e das medicinais, as espécies M. vilosa, L. Alba, C. citratus, C. winterianus e P. boldus também não apresentaram galhas. Assim, conclui-se que as plantas ornamentais são potenciais introdutoras de nematoide das galhas em áreas indenes e que as medicinais, podem ser utilizadas em programas de rotação de culturas em função da pouca susceptibilidade ao nematoide das galhas.

The influence of L-phenylalanine, methyl jasmonate and sucrose concentration on the accumulation of phenolic acids in Exacum affine Balf. f. ex Regel shoot culture.

Phenolic acids are an important group of plant secondary metabolites with various, valuable therapeutic properties. Apart from plants growing in the open air, tissue cultures can be an alternative source of the secondary metabolites. The yield of their accumulation in in vitro cultures can be increased by different methods, including culture medium supplementation with precursors, elicitors and changing the standard amounts of the medium components. The purpose of this study was to investigate the influence of the precursor (L-phenylalanine), the elicitor (methyl jasmonate) and a higher sucrose concentration on the phenolic acids accumulation in the agitated shoot cultures of Exacum affine Balf. f. ex Regel (Gentianaceae). Qualitative and quantitative analyses of the phenolic acids in methanolic extracts from the biomass were conducted by applying the HPLC method. Fourteen phenolic acids and cinnamic acid were found in all samples. The total content of free phenolic acids increased from approximately 0.242% to 0.635% (2.6-fold) and the total content of the whole phenolic acids (free and bound) - from 0.712% to 1.160% (1.6-fold). The studies show that the best variant for the accumulation of most of the identified phenolic acids contained 6% of sucrose (double the standard amount), L-phenylalanine 1.6 gL(-1) of medium and methyl jasmonate 100 μM. The analysis of the results in the experiment presented here showed that it is possible to increase the accumulation of the phenolic acids in Exacum affine shoot cultures - by adding the precursor (L-phenylalanine), the elicitor (methyl jasmonate) and by increasing the sucrose concentration.

Ocorrência de nematóides fitoparasitos em plantas ornamentais nos Estados de São Paulo e Minas Gerais, Brasil.

O objetivo do presente trabalho foi o de discutir a importância das principais espécies de nematóides encontradas associadas a plantas ornamentais cultivadas nos Estados de São Paulo e Minas Gerais, com base em dados de distribuição geográfica, de novas ocorrências e relativos à sintomatologia. Nematóides foram extraídos de 5 g de raízes e identificados sob microscópio. As espécies mais freqüentes foram<i> Meloidogyne javanica</i> (38% das amostras), <i>M. incognita</i> (19%) e <i>Helicotylenchus dihystera</i> (11%). Constituíram novas ocorrências no Brasil: <i>M. incognita em Gloxinia sp., Arundina graminifolia</i> (orquídea-bambu) e <i>Aptenia cordifolia</i> (rosinha do sol);<i> M. javanica em A. graminifolia, Hibiscus spp., Gloxinia sp., Eustoma grandiflorum</i> (lisianto), <i>Heliconia rostrata</i> (falsa ave do paraíso), <i>Graptophyllum pictum</i> (graptofilo), <i>Holmskioldia sanguinea</i> (chapéu-chinês) e<i> Exacum affine</i> (violeta-alemã); <i>Pratylenchus brachyurus em E. grandiflorum, Cattleya sp</i>. (orquídea) e diferentes cultivares de <i>Lilium</i> sp. (lírio); <i>Helicotylenchus dihystera em E. grandiflorum, Lilium sp., Impatiens balsamina e A. cordifolia; H. multicinctus em Pachystachys lutea</i> (camarão amarelo);<i>H. pseudorobustus em Heliconia sp., e Cactodera cacti em Schlumbergera sp.</i> (flor de maio).