Cellulose is the main polymer that gives strength to the cell wall and consists of crystalline-mi... more Cellulose is the main polymer that gives strength to the cell wall and consists of crystalline-microfibrils and amorphous-matrix cellulose located in the primary and secondary cell walls of the plants. In the Cactaceae family, there are studies on the composition of lignin but not on the composition of cellulose. Therefore, the objective of his work is to analyze the chemical composition and distribution of cellulose in the cells of the xylem tissue. Twenty-five species of Cactaceae were collected, dried, and milled. The extractables were removed until obtaining extractive-free wood. Subsequently, cellulose was purified, readings with Fourier transform infrared spectroscopy were made, and the crystallinity indexes were calculated. In addition, for the anatomical analysis of wood, stem sections for each plant were fixed, cut, and stained with safranin O / fast green to observe them under the epifluorescence microscope with three excitation and emission bands. The results showed that ...
It is surmised that domestication has reduced geneticvariability in the common bean (Phaseolusvul... more It is surmised that domestication has reduced geneticvariability in the common bean (Phaseolusvulgaris L.). However, little is known about leaf anatomy responses to water stress in wild or domesticated forms ofP. vulgaris. In this study,anatomical variation was evaluated in watered and water stressed plants of wild and domesticated genotypes of P.vulgaris from Mexico, growing under greenhouse conditions. Five terminal leaflets
ABSTRACT Abstract— Echinocereus is the third most species-rich genus in the Cactaceae. It is dist... more ABSTRACT Abstract— Echinocereus is the third most species-rich genus in the Cactaceae. It is distributed in North America from Mexico to the central U. S. A. Previous molecular phylogenetic studies have indicated that the genus is polyphyletic, but incomplete taxon sampling and unclear resolution have hindered the formal re-evaluation of generic and infrageneric circumscriptions. To address this problem, we analyzed six plastid regions (matK, rbcL, psbA-trnH, trnQ-rps16, rpl16, and trnL-F) using maximum parsimony and Bayesian inference criteria for 59 species, including all previously proposed infrageneric entities and representing the full range of morphological variation known in the genus. Our results support the monophyly of Echinocereus if E. pensilis is excluded and reestablished as the monotypic genus Morangaya. Two additional morphological characters, erumpent flower buds and green stigma lobes, further support the circumscription of Echinocereus sensu stricto. Phylogenetic analyses recovered nine main clades in Echinocereus s. s., one of which corresponds to the Triglochidiati section; the remaining clades did not correspond to any other recognized sections. We suggest a re-evaluation of previously proposed infrageneric entities.
ABSTRACT El efecto de la hidratación temporal sobre la germinación de tres cactáceas que habitan ... more ABSTRACT El efecto de la hidratación temporal sobre la germinación de tres cactáceas que habitan en la isla Mazocahui I, norte de Sinaloa, se estimó mediante la aplicación de 0, 10 y 20 ciclos de hidratación/deshidratación en condiciones de laboratorio. Más del 87% de las semillas de Mammillaria mazatlanensis, Stenocereus alamosensis y S. thurberi var. thurberi germinaron en los tratamientos considerados, sin mostrar diferencias significativas entre ellos. La hidratación temporal pareciera activar los procesos metabólicos de las semillas de las tres especies y reducir el tiempo medio de germinación en las especies de Stenocereus, las cuales tienen el mismo comportamiento, esto es, alcanzan el 50% de su germinación total al tercer día, mientras que el control se demoró en 12-36 h. Por el contrario, M.mazatlanensis tuvo una demora de 22-31 h respecto al control. Palabras clave: Cactáceas, ciclos de hidratación/deshidratación, desierto costero de Topolobampo, germinación, humedad, tiempo medio de germinación.
ABSTRACT The stem epidermis of 23 species and three subspecies of Ferocactus Britton & Ro... more ABSTRACT The stem epidermis of 23 species and three subspecies of Ferocactus Britton & Rose from the tribe Cacteae-Cactaceae are described and compared using scanning electron and light microscopy. Epidermal-hypodermal samples were removed, prepared for observation, and analyzed using a similarity method. Our observations showed that most epidermal cells had an elongate-tetragonal outline with straight anticlinal walls. However, S and U-undulated anticlinal walls occurred in F. glaucescens (DC.) Britton & Rose and F. peninsulae (Engelm. ex F.A.C. Weber) Britton & Rose (Cactaceae). The microrelief of the anticlines was flat and inconspicuous or striate. The periclinal wall relief varied from none to rugose or verrucose among species; 89% of the studied species had slightly sunken or sunken parallelocytic stomata with 2 or 3 pairs of subsidiary cells. Cuticle thickness varied from 2.54 µm in F. histrix (DC.) G.E. Linds to 39.74 µm in F. flavovirens (Scheidw.) Britton & Rose and their thickness is not related to environment. Silica bodies in the hypodermis cell lumina are present in 90% of the species studied. The epidermal characters of the Ferocactus species have been described in other members of Cactoideae, none of them can be postulated as possible synapomorphies to the genus level. Pustules, which are a cutin accumulations on the outer epidermal walls are distinctive feature of F. emoryi (Engelm.) Orcutt, and here are described for the first time for the Cactaceae. The phenogram revealed three groups, and F. haematacanthus (Salm-Dyck) Bravo was revealed as the most distinct species within the genus as well as F. histrix. Both were the early derived species in the most recent phylogeny. A combination of epidermal characters can help to distinguish some Ferocactus species, but failed to support the infrageneric classifications. However, some groups of species based on their epidermal similarities agree with some clades in the most recent phylogeny.
Histological research has provided valuable information contributing to our understanding of the ... more Histological research has provided valuable information contributing to our understanding of the impacts of air pollution on plant species (Thomson 1975; Weber and Grulke 1995). Tissue modifications may appear before visible symptoms in leaves and stems. Tissue modifications can also be used as indicators of air pollution effects (Bernal et al. 2002; Fincher and Alscher 1992). Anatomical studies help elucidate biochemical and physiological changes that may possibly occur in plants exposed to pollutants, especially those changes related to net photosynthesis, allocation of resources (carbohydrates), and mechanisms of injury response. Xylem studies using dendrochronological techniques make it possible to reconstruct past events in forest communities and to determine tree growth rates in species exposed to air pollutants based on changes in ring width, density, and element composition (Weber and Grulke 1995).
... All species have opposite leaves and inflorescences with five accrescent and usually connate ... more ... All species have opposite leaves and inflorescences with five accrescent and usually connate involucral bracts, which subtend one or more flowers (Standley and Steyermark 1946; Fay 1980; Le Duc 1995; Pool 2000; Spellenberg 2001, 2003). ...
Cellulose is the main polymer that gives strength to the cell wall and consists of crystalline-mi... more Cellulose is the main polymer that gives strength to the cell wall and consists of crystalline-microfibrils and amorphous-matrix cellulose located in the primary and secondary cell walls of the plants. In the Cactaceae family, there are studies on the composition of lignin but not on the composition of cellulose. Therefore, the objective of his work is to analyze the chemical composition and distribution of cellulose in the cells of the xylem tissue. Twenty-five species of Cactaceae were collected, dried, and milled. The extractables were removed until obtaining extractive-free wood. Subsequently, cellulose was purified, readings with Fourier transform infrared spectroscopy were made, and the crystallinity indexes were calculated. In addition, for the anatomical analysis of wood, stem sections for each plant were fixed, cut, and stained with safranin O / fast green to observe them under the epifluorescence microscope with three excitation and emission bands. The results showed that ...
It is surmised that domestication has reduced geneticvariability in the common bean (Phaseolusvul... more It is surmised that domestication has reduced geneticvariability in the common bean (Phaseolusvulgaris L.). However, little is known about leaf anatomy responses to water stress in wild or domesticated forms ofP. vulgaris. In this study,anatomical variation was evaluated in watered and water stressed plants of wild and domesticated genotypes of P.vulgaris from Mexico, growing under greenhouse conditions. Five terminal leaflets
ABSTRACT Abstract— Echinocereus is the third most species-rich genus in the Cactaceae. It is dist... more ABSTRACT Abstract— Echinocereus is the third most species-rich genus in the Cactaceae. It is distributed in North America from Mexico to the central U. S. A. Previous molecular phylogenetic studies have indicated that the genus is polyphyletic, but incomplete taxon sampling and unclear resolution have hindered the formal re-evaluation of generic and infrageneric circumscriptions. To address this problem, we analyzed six plastid regions (matK, rbcL, psbA-trnH, trnQ-rps16, rpl16, and trnL-F) using maximum parsimony and Bayesian inference criteria for 59 species, including all previously proposed infrageneric entities and representing the full range of morphological variation known in the genus. Our results support the monophyly of Echinocereus if E. pensilis is excluded and reestablished as the monotypic genus Morangaya. Two additional morphological characters, erumpent flower buds and green stigma lobes, further support the circumscription of Echinocereus sensu stricto. Phylogenetic analyses recovered nine main clades in Echinocereus s. s., one of which corresponds to the Triglochidiati section; the remaining clades did not correspond to any other recognized sections. We suggest a re-evaluation of previously proposed infrageneric entities.
ABSTRACT El efecto de la hidratación temporal sobre la germinación de tres cactáceas que habitan ... more ABSTRACT El efecto de la hidratación temporal sobre la germinación de tres cactáceas que habitan en la isla Mazocahui I, norte de Sinaloa, se estimó mediante la aplicación de 0, 10 y 20 ciclos de hidratación/deshidratación en condiciones de laboratorio. Más del 87% de las semillas de Mammillaria mazatlanensis, Stenocereus alamosensis y S. thurberi var. thurberi germinaron en los tratamientos considerados, sin mostrar diferencias significativas entre ellos. La hidratación temporal pareciera activar los procesos metabólicos de las semillas de las tres especies y reducir el tiempo medio de germinación en las especies de Stenocereus, las cuales tienen el mismo comportamiento, esto es, alcanzan el 50% de su germinación total al tercer día, mientras que el control se demoró en 12-36 h. Por el contrario, M.mazatlanensis tuvo una demora de 22-31 h respecto al control. Palabras clave: Cactáceas, ciclos de hidratación/deshidratación, desierto costero de Topolobampo, germinación, humedad, tiempo medio de germinación.
ABSTRACT The stem epidermis of 23 species and three subspecies of Ferocactus Britton & Ro... more ABSTRACT The stem epidermis of 23 species and three subspecies of Ferocactus Britton & Rose from the tribe Cacteae-Cactaceae are described and compared using scanning electron and light microscopy. Epidermal-hypodermal samples were removed, prepared for observation, and analyzed using a similarity method. Our observations showed that most epidermal cells had an elongate-tetragonal outline with straight anticlinal walls. However, S and U-undulated anticlinal walls occurred in F. glaucescens (DC.) Britton & Rose and F. peninsulae (Engelm. ex F.A.C. Weber) Britton & Rose (Cactaceae). The microrelief of the anticlines was flat and inconspicuous or striate. The periclinal wall relief varied from none to rugose or verrucose among species; 89% of the studied species had slightly sunken or sunken parallelocytic stomata with 2 or 3 pairs of subsidiary cells. Cuticle thickness varied from 2.54 µm in F. histrix (DC.) G.E. Linds to 39.74 µm in F. flavovirens (Scheidw.) Britton & Rose and their thickness is not related to environment. Silica bodies in the hypodermis cell lumina are present in 90% of the species studied. The epidermal characters of the Ferocactus species have been described in other members of Cactoideae, none of them can be postulated as possible synapomorphies to the genus level. Pustules, which are a cutin accumulations on the outer epidermal walls are distinctive feature of F. emoryi (Engelm.) Orcutt, and here are described for the first time for the Cactaceae. The phenogram revealed three groups, and F. haematacanthus (Salm-Dyck) Bravo was revealed as the most distinct species within the genus as well as F. histrix. Both were the early derived species in the most recent phylogeny. A combination of epidermal characters can help to distinguish some Ferocactus species, but failed to support the infrageneric classifications. However, some groups of species based on their epidermal similarities agree with some clades in the most recent phylogeny.
Histological research has provided valuable information contributing to our understanding of the ... more Histological research has provided valuable information contributing to our understanding of the impacts of air pollution on plant species (Thomson 1975; Weber and Grulke 1995). Tissue modifications may appear before visible symptoms in leaves and stems. Tissue modifications can also be used as indicators of air pollution effects (Bernal et al. 2002; Fincher and Alscher 1992). Anatomical studies help elucidate biochemical and physiological changes that may possibly occur in plants exposed to pollutants, especially those changes related to net photosynthesis, allocation of resources (carbohydrates), and mechanisms of injury response. Xylem studies using dendrochronological techniques make it possible to reconstruct past events in forest communities and to determine tree growth rates in species exposed to air pollutants based on changes in ring width, density, and element composition (Weber and Grulke 1995).
... All species have opposite leaves and inflorescences with five accrescent and usually connate ... more ... All species have opposite leaves and inflorescences with five accrescent and usually connate involucral bracts, which subtend one or more flowers (Standley and Steyermark 1946; Fay 1980; Le Duc 1995; Pool 2000; Spellenberg 2001, 2003). ...
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