scholarly journals Ultrastructural study of ectomycorrhizas on Pinus caribaea Morelet. var. hondurensis Barr. & Golf. seedlings

2004 ◽  
Vol 18 (1) ◽  
pp. 1-7 ◽  
Author(s):  
Eduardo Gross ◽  
Lilian I. Thomazini Casagrande ◽  
Flávio Henrique Caetano
Keyword(s):  
Ultrastructural Study ◽  
Lateral Roots ◽  
Endoplasmatic Reticulum ◽  
Pinus Caribaea ◽  
Cortical Cells ◽  
Electron Dense Material ◽  
Narrow Region ◽  
Ultrastructural Characteristics ◽  
Pinus Caribaea Morelet ◽  
Peripheral Cytoplasm

The ultrastructure of ectomycorrhizas formed between Pinus caribaea var. hondurensis inoculated with Pisolithus tinctorius (Pers.) Coker & Couch and Telephora terrestris (Ehrenb.) Fr. was analyzed just before the transplant of these seedlings to the field to ascertain if fungi are established in the roots. Ectomycorrhizal fungi formed a well-developed compact mantle in lateral roots. Vacuoles, nuclei and dolipore septa were observed in mantle hyphae and numerous nuclei, endoplasmatic reticulum and polymorphic mitochondria were frequently located in the cytoplasm of Hartig net hyphae adjacent to plant cortical cells. Highly vacuolated cortical cells contained droplets of electron-dense material, nucleus and some organelles were observed in a narrow region of peripheral cytoplasm. The ectomycorrhizas of P. caribaea var. hondurensis exhibited typical ultrastructural characteristics of a compatible and physiological active association.

scholarly journals ARTIFICIAL NEURAL NETWORKS FOR MODELING HYPSOMETRIC RELATIONSHIPS OF Pinus caribaea Morelet var. caribaea Barr. & Golf.

2018 ◽  
Vol 36 (4) ◽  
pp. 891
Author(s):  
Ouorou Ganni Mariel GUERA ◽  
José Antônio Aleixo SILVA ◽  
Rinaldo Luiz Caraciolo FERREIRA ◽  
Héctor Barrero MEDEL ◽  
Daniel Álvarez LAZO
Keyword(s):  
Neural Networks ◽  
Artificial Neural Networks ◽  
Sample Size ◽  
Regression Models ◽  
Growth Models ◽  
Pinus Caribaea ◽  
Three Stages ◽  
Artificial Neural ◽  
Sigmoidal Growth ◽  
Pinus Caribaea Morelet

The present study was carried out to compare the performances of regression models and Artificial Neural  Networks (ANNs) in hypsometric relationships modeling and to analyze the influence of ANN type  and sample size on ANN performance. The database was consisted by 65 circular plots of 500 m² in which  Diameter at Breast Height - DBH (cm) and Total Height - Ht (m) of 2538 trees were measured in plantations of Pinus caribaea var. caribaea in Macurije forest company, Cuba. The study was carried out in three  stages: i) Fit of traditional hypsometric models and sigmoidal growth models; ii) ANNs training and comparison of the selected ANN with the regression model selected; iii) Analysis of sample size and ANN type influences on the estimates precision by means of a completely random experimental design with 5x2 factorial arrangement, with the factors sample size (N) and ANN type (R). The results indicated that the best equation to estimate trees heights was that of Gompertz. The ANNs MLP 1-4-1 and MLP 8-4-1 were superior to the selected equation (Gompertz). Multi-Layer Perceptron ANNs generated more accurate estimates and their performances were less influenced by the sample size.

scholarly journals Estimation of above ground biomass of a Pinus caribaea Morelet stand in lower Hantana

2009 ◽  
Vol 37 (3) ◽  
pp. 195 ◽  
Author(s):  
I.M. Ambagahaduwa ◽  
N. Prasad ◽  
I.A.U.N. Gunatilleke ◽  
G. Seneviratne ◽  
C.V.S. Gunatilleke
Keyword(s):  
Above Ground Biomass ◽  
Pinus Caribaea ◽  
Ground Biomass ◽  
Pinus Caribaea Morelet

PLASMODESMAL MODIFICATIONS AND DISTRIBUTION OF TOSPO VIRUS IN POTATO AND TOMATO

1999 ◽  
Vol 47 (4) ◽  
pp. 245-250 ◽  
Author(s):  
Ishwar D. Garg ◽  
S.M. Paul Khurana
Keyword(s):  
Long Distance ◽  
Phloem Tissue ◽  
Cortical Cells ◽  
Electron Dense Material ◽  
Phloem Parenchyma ◽  
Long Distance Transport ◽  
Infected Tomato ◽  
Sieve Tubes ◽  
The One ◽  
Distance Transport

The tospovirus isolate on tomato was found to be systemic while the one on potato was non-systemic. The virus was present in all the tissues except xylem vessels in tomato, while it was often found only in the cortical cells of potato stems. Virions were detected in all cells of phloem tissue in tomato, while none were present in the case of potato. Plasmodesmata were present between phloem parenchyma and the phloem sieve tubes in infected tomato but none were present in infected potato. There were pronounced plasmodesmal changes in response to infection in tomato. These included dissolution of the desmotubule (central rod-like structure), making the plasmodesmata pore-like structures with a diameter of ca. 45 nm, which contained electron-dense material, presumably ribonucleoprotein of the virus. No such changes were found in infected potato. These results of comparative studies suggested that the virus was non-systemic in potato due to its non-loading into the phloem and consequently lacked long distance transport.

scholarly journals Nodulation of Aeschynomene afraspera and A. indica by Photosynthetic Bradyrhizobium Sp. Strain ORS285: The Nod-Dependent Versus the Nod-Independent Symbiotic Interaction

2011 ◽  
Vol 24 (11) ◽  
pp. 1359-1371 ◽  
Author(s):  
Katia Bonaldi ◽  
Daniel Gargani ◽  
Yves Prin ◽  
Joel Fardoux ◽  
Djamel Gully ◽  
...  
Keyword(s):  
Fluorescent Protein ◽  
Lateral Roots ◽  
Root Hairs ◽  
Infection Process ◽  
Cortical Cells ◽  
Symbiotic Interaction ◽  
Root Cortex ◽  
Bradyrhizobium Sp ◽  
Infected Cells ◽  
Green Fluorescent

Here, we present a comparative analysis of the nodulation processes of Aeschynomene afraspera and A. indica that differ in their requirement for Nod factors (NF) to initiate symbiosis with photosynthetic bradyrhizobia. The infection process and nodule organogenesis was examined using the green fluorescent protein–labeled Bradyrhizobium sp. strain ORS285 able to nodulate both species. In A. indica, when the NF-independent strategy is used, bacteria penetrated the root intercellularly between axillary root hairs and invaded the subepidermal cortical cells by invagination of the host cell wall. Whereas the first infected cortical cells collapsed, the infected ones immediately beneath kept their integrity and divided repeatedly to form the nodule. In A. afraspera, when the NF-dependent strategy is used, bacteria entered the plant through epidermal fissures generated by the emergence of lateral roots and spread deeper intercellularly in the root cortex, infecting some cortical cells during their progression. Whereas the infected cells of the lower cortical layers divided rapidly to form the nodule, the infected cells of the upper layers gave rise to an outgrowth in which the bacteria remained enclosed in large tubular structures. Together, two distinct modes of infection and nodule organogenesis coexist in Aeschynomene legumes, each displaying original features.

scholarly journals Contribución para el diagnóstico y control de los descortezadores  del género ips(coleoptera: scolytidae) en los bosques de pinos de cuba

Ra Ximhai ◽  
2009 ◽  
pp. 281-296 ◽  
Author(s):  
René Alberto López Castilla ◽  
Fidel Góngora Rojas ◽  
Celia Guerra Rivero ◽  
Enrique de Zayas Izaguirre ◽  
Antonio Fernández Vera ◽  
...  
Keyword(s):  
Pinus Caribaea ◽  
Impacto Económico ◽  
Pinus Caribaea Morelet

Cuatro especies de pinos son endémicas en Cuba y tienen importancia en gran amplitud, desde la Conservación de los Recursos Genéticos Forestales a nivel regional hasta la mitigación del cambio climático. Su importancia económica se debe a que forman rodales puros de crecimiento rápido y de fuste recto. Los descortezadores del género Ips De Geer (Coleoptera: Scolytidae) junto a los hongos asociados del complejo Ophiostomatoid (Ceratocystidaceae: Microascales Phylum Ascomycotina) son los que causan los mayores daños en las plantaciones de pinos en Cuba. El manejo de este daño se basó principalmente en la tala de todos los árboles infestados y la aplicación de insecticidas organosintéticos con las consecuentes afectaciones al medio ambiente aparte de pérdidas económicas. En este trabajo mediante el desarrollo de experimentos con diseño de trozas de pinos al azar y muestreos sistemáticos en árboles de pinos se determinó la especie de Ips más nociva y la especie de pinos más vulnerables en la región occidental. Además se definió un índice de umbral de daños y los tratamientos suficientemente efectivos con productos biológicos en la región central. Estos resultados se integraron e introdujeron en forma de metodología de manejo de los descortezadores en un área de plantaciones de Pinus caribaea Morelet var. caribaea ( Punta Felipe, Villa Clara, Cuba) después del desarrollo de un brote epidémico de este complejo nocivo y se demostró que era posible controlar esta plaga sin realizar las talas de todos los árboles afectados ni la aplicación de insecticidas organosintéticos. Por lo que este trabajo tiene un impacto ambiental positivo, contribuyendo a la conservación saludable de los bosques de pinos y un impacto económico debido al ahorro de divisas por concepto de insecticidas dejados de aplicar y además por disminuir las pérdidas de incremento de madera.

Ultrastructural Morphology of the Plastids in Ferocactus Latispinus (Haworth)

1981 ◽  
Vol 39 ◽  
pp. 648-649
Author(s):  
E. R. Rivera
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Apical Meristem ◽  
Plant Cells ◽  
Cortical Cells ◽  
Conventional Transmission Electron Microscopy ◽  
Meristematic Cells ◽  
Dense Cytoplasm ◽  
Transmission Electron ◽  
Peripheral Cytoplasm

Mature plants of Ferocactus latispinus were divided into the apical meristem, cortical and cambial tissue, and young and mature photosynthetic tissue. Pieces 2x2x4 mm were fixed in 0.075 M PIPES buffered 5% glutaraldehyde and further treated for conventional transmission electron microscopy.The shoot meristematic cells contained dense cytoplasm with a few small vacuoles. All organelles expected to be found in unspecialized plant cells were present. The proplastids were 1-2 diameters larger than mitochondria. Some of these plastids were elongated and most contained small amounts of lipid globules in the stroma (Fig. 1). In addition, phytoferritin was sometimes found in the stroma. No starch was found in these organelles. The thylakoids were poorly developed, and when there were no inclusions in the stroma, proplastids were difficult to distinguish from mitochondria (Fig. 1).Cortical cells had very large, well-developed vacuoles. The organelles were restricted to the peripheral cytoplasm of the cell and to a few transvacuolar cytoplasmic strands.

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