David Flores Román

Germinación y crecimiento de plántulas de Phaseolus vulgaris L. en condiciones de salinidad

Beans are sensitive to salinity. In Mexico in the autumn-winter cycle, bean production is performed under conditions of residual moisture. Under these conditions, salinity problems are increased and are reflected in the reduction in the percentage of germination, growth and underground and aerial performance. The levels of damage are different between varieties. In this research, conducted in Nayarit in 2012 in a greenhouse at a temperature of 28.1 oC, the physiological response to salinity induced with sodium chloride, three bean varieties of higher production in Nayarit in the germination stage and seedling was evaluated. The experimental design was completely randomized using three replicates per treatment. Pinto bean germination decreased 54.7% to 9 dS m -1 and beans Azufrado 30.3%. In seedlings, the stem length difference between the control (T0) and the highest treatment (T6) was 2.4, 4 and 3.2 cm for the Negro, Pinto and Azufrado respectively beans. The difference in root length between T0 and T6, was 13.1, 13.4 and 12.1 cm for the Negro, Pinto and Azufrado respectively beans. It as the electrical conductivity increased germination rate decreased. The Azufrado beans were the toughest and the most affected Pinto. The stem length, fresh weight and dry weight of seedling decreased and increased stem diameter. The length, fresh weight and dry root weight decreased gradually.

Carbono orgánico de la hojarasca en los bosques de la reserva de la Biósfera Mariposa Monarca, caso santuario sierra Chincua, México

It was estimated the percentage of organic carbon (CO) and CO captured in the leaf litter of the sierra Chincua forest in the Monarch Butterfly Biosphere Reserve, Mexico. The sampling of the litter was carried out in eight places, from a square of 0.25 m2 (50 cm x 50 cm), in the laboratory it was determined the total percentage of CO, proving to the site 3 and 9 L horizon and a range of 26.59 to 54.26 % and the rest of places and horizon F, range of 36.32 to 40.41 %. The CO stored in t ha-1, at the level of horizons, the F varies from 8.82 to 35.96 t ha-1, the L varies between 1.41 and 34.10t ha-1. At place level, the 2, 3 and 9 varies between 1.41 and 8.82 t ha-1, in the other places it varies between 22.97 to 35.96 t ha-1. Without a statistical difference in the sampling place, horizons and physiography for percent and storage of organic carbon (F = 0.0776 , 0.7270 , 0.3157 for % CO and F = 0.8265 , 0.5807 , 0.3915 for CO stored) respectively. In comparison of averages, in the sampling places there are five groups of the percent of CO, ranging from 26.59 to 54.26 %, for carbon stored there is no statistical difference. It was concluded that the percentage of carbon from the litter presents wide variation in the percentages of CO and stored CO by the litter in t ha-1