Cowpea and kidney bean plants were grown in a hydroponic system, and the effect of calcium silicate supplied to the nutrient solution under salt stress was investigated. The plants were subjected to four different treatments: (1) nutrient solution alone (C), (2) nutrient solution + 40 mmol l )1 NaCl (NaCl), (3) nutrient solution + 40 mmol l )1 NaCl + 0.5 mmol l )1 CaSiO 3 (NaCl + Si 1 ) and (4) nutrient solution + 40 mmol l )1 NaCl+1 mmol l )1 CaSiO 3 (NaCl + Si 2 ). The results showed that, in both species, salinity reduced all growth variables but silicate supplementation however partly overcame this growth reduction. Addition of silicate in NaCl-stressed plants maintained membrane permeability. Net photosynthesis, chlorophyll content, stomatal conductance and transpiration were higher in plants under control treatment, and the inclusion of silicate in the nutrient solution resulted in a slight increase in these plant parameters. Intercellular CO 2 was slightly higher in plants under silicate treatment than in plants under control or NaCl treatment. Calcium concentration in shoots and roots in both species was slightly higher in the treatments where silicate was added. Potassium concentration for salt treatment was reduced in shoot and root of both species in the absence of silicate. Sodium and chloride concentration in shoots and roots in both species were slightly higher in the presence of NaCl and were slightly reduced in the plants under silicate treatments. The results suggest that, in hydroponically grown plants, the inclusion of silicate in the nutrient solution is beneficial because it improves growth, physiological parameters and may contribute to a more balanced nutrition by enhancing nutrient uptake under NaCl-stressed conditions. Added calcium silicate may ameliorate the parameters affected by high salinity, may reduce sodium and chloride, and can slightly increase calcium and potassium concentrations in shoots and roots of salt-stressed cowpea and kidney bean.

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Resumen. Por sus características, la cochinilla silvestre ofrece perspectivas de aprovechamiento como fuente de carmín y para el mejoramiento genético de la grana fi na. Por lo anterior, se estableció una multiplicación y crianza de cochinilla silvestre, proveniente de la zona árida del norte de México para caracterizarla, utilizando como hospedero a Opuntia megacantha Salm Dyck. Los resultados indican que la especie silvestre pertenece al género-especie Dactylopius opuntia. Se determinó la presencia de partenogénesis en hembras. La duración de los estadios biológicos depende del sexo del insecto; el adulto hembra permaneció durante 38.4 días y los machos 4.2 días, mientras que los primeros estadios ninfales duraron 18.1-19.8 días. El ciclo biológico de las hembras fue de 77 días mientras que el de los machos fue de 43 días. Para las hembras se estimó un periodo de preoviposición de 18.8 días, manteniéndose en oviposición durante 21 días con un promedio de 131 insectos por hembra. La proporción sexual hembras: machos fue 1:1. El tipo de reproducción fue predominantemente sexual, aunque hubo hembras partenogénicas. Este es el primer reporte de Dactylopius opuntiae como cochinilla silvestre asociada a la zona árida

Abies spp. in general have been shown to need a period of cold stratification to break dormancy and germinate, but this can be very time consuming. In this study, hydropriming by itself and in combination with biopriming was carried out on Abies hickelii and Abies religiosa seeds. For biopriming, three species of plant growth promoting rhizobacteria ( Pseudomonas fluorescens, P. putida and Bacillus subtilis) were tested. The purpose was to determine if germination and growth could be improved for these two endangered species. Our results demonstrated that treating A. hickelii and A. religiosa with both hydropriming and biopriming with certain strains of Plant Growth-Promoting Rhizobacteria (PGPR) could improve germination rates up to 91% for A. hickelii and up to 68% for A. religiosa. Importantly, these treatments showed no significant negative impact on the growth of A. religiosa and actually improved growth in A. hickelii. The application of OPEN ACCESSForests 2015, 6 3110 both hydropriming and biopriming offer possibly an alternative methodology to improve germination, survival and preservation of these fir tree species of Mexico that are at risk of extinction.

Salicornia bigelovii is a novel crop for salty soils, which can contribute to arid-zone management where irrigation with salty water, including sea water, is now a necessity. Nitrogen fixation by bacteria associated with the roots of S. bigelovii and similar halophytes is an important source of available nitrogen in salt marsh ecosystems. However, the diversity of the rhizosphere of Salicornia is unknown. Five areas around the Bay of La Paz in Baja California Sur, Mexico were sampled to detect nitrogen-fixing bacteria associated with this halophyte; from these, 18 colonies were isolated. Only one showed high acetylene reduction activity. This bacterium was identified as Klebsiella pneumoniae. The effects of K. pneumoniae were evaluated at the germination and early seedling growth stages of two genotypes of S. bigelovii (Ôwild genotypeÕ and cultivar SOS-10), as an alternative crop for semiarid and saline environments. This bacterium, in conjunction with Azospirillum halopraeferens, was tested for growth-promoting ability when inoculated on S. bigelovii genotypes under various saline concentration conditions. During germination and early seedling growth, K. pneumoniae showed high specificity for the wild S. bigelovii genotype, while A. halopraeferens was more specific for the improved S. bigelovii genotype SOS-10. This is the first report of K. pneumoniae as a nitrogen-fixing bacterium associated with the oilseed S. bigelovii, a novel halophyte crop. A reliable biological method, based on beneficial bacteria, is suggested to help maintain or improve the fertility of soils sustaining Salicornia fields.

Polyploidy is a biotechnology that in the last decade had provided with an improvement method for mollusks in aquaculture. Triploids have three sets of chromosomes rather than the two carried by diploids. The third set has an effect on chromosomes synapsis, producing sterility during reproduction. That sterility is the most accepted cause for the better growth seen in triploids. Artificial induction to triploidy has some problems, which can be solved by the existence of tetraploids, which could be mated to diploids to produce biological triploids. Control strategies based on prevention of disease and methods that slow the spread of such diseases. Therefore, proper management of diseases affecting the tomato crop, knowledge and understanding of the diagnosis and its infectious cycle is vital and to establish effective control measures.However, the literature is limited when it comes to auscultating information related with the poliploidía in mollusks, it´s origin and the multiple biotechnologies that develop contemporary. This study was conducted to assess and meet the trend of existing research on polyploidy in commercially important shellfissh.