We evaluate the globulins and total proteins composition in megagametophytes tissue from seeds collected in a natural population of Pinus hartwegii located at Cofre de Perote, Veracruz. Electrophoresis was performed in a discontinuous system of polyacrylamide gels (PAGE). Results shown a good resolution and repeatability in obtained protein profile. It was detected the presence of four haplotypes. The trees under study were classified in three groups. The group I that contained the majority of evaluated trees (70 %), was characterized for the presence of haplotype I. Our results suggest the presence of certain inbreeding degree in this population.

Abies religiosa forests in Ajusco (Mexico) are in declination. It is required to restore populations using some survivor trees from affected slopes. The aims were to evaluate in vitro environmental for aseptic establishment of seeds and select the ad hoc explants for plantlet production in A. religiosa. Disinfectants were tested (H2O2, C2H5OH, NaOCl) for in vitro germination. Explants were evaluated (complete seed, complete or half -transversal cut- isolated embryo, and cotyledons and first leaves from in vitro germinated plantlets) for their in vitro establishment. The best treatment for A. religiosa seed disinfection is dips it in 3% v/v H2O2 and shakes 24 h. The best explants for in vitro propagation were complete seed and first leaves.

In the occidental section of Sierra de los Órganos (locality of San Andrés, province of Pinar del Río) most of its soils are red ferralitic leached in hillside condition. Its exposure to erosive processes can be verified. However, there are not enough references about assessment of natural factors influence over those processes. Through the present work there have been calculated potential and current erosion risk indexes taking published data in1989 (Departamento de Suelos del Ministerio de la Agricultura, 1989), and gathered data by fieldwork in 2005. These indexes were used for soil maps construction by mean of GIS tools. The results show a trend to morphogenesis and make predictable a similar behavior in the next several years whether following the current land use customs.

The shrub “vara de perlilla” (Symphoycarpos microphyllus H.B.K.) is broadly employed to manufacture Christmas crafts and to make brooms. The species is not under management and consequently the natural populations are being reduced. In this work was studied the propagation of such species using branch cuttings. The cuttings were collected from Nanacamilpa, Tlaxcala state, Mexico, by April 2005, and were planted in a nursery bed at the forest nursery of the División de Ciencias Forestales, Universidad Autónoma Chapingo, México. It was established a randomized complete blocks experimental design, with five replications. The treatments were: application of Radix® 10,000, Raizone plus, and a control. It was studied survival, length of shoot and biomass. A mixed procedure was utilized for the statistical analysis. It was found that the higher survival 77.6 % and the longest shoots 50.5 cm both corresponded to the Radix® 10,000 treatment.

A “Vara de perlilla” (Symphoricarpos microphyllus H.B.K.) plantation was established in the forest nursery of the División de Ciencias Forestales, Universidad Autónoma Chapingo. The objective was to study survival and growth under different solar radiation conditions. The shrubs were planted under a pine forest plantation in different light conditions. With a digital camera with hemispheric lens and the Hemiview program©, were measured direct and diffuse solar radiation, and visible sky. From the shrubs was recorded survival, number and length of branches, shoot and root biomass and total biomass. The probability of mortality was obtained with a logistic model, using as explanatory variable direct solar radiation. Also was employed linear regression. The logistic model was significant (P= 0.0970), with higher mortality at higher light levels. The lineal regressions were not significant or had a verly low R2.

The relations of the organisms in the nature are based on two cycles, one of matter and the other of energy, these cycles give origin to the food chains which give origin to the three food levels; autotrophs, herbivorous and carnivores. For the case of freshwater fishes, the young organisms live and they are fed in the border and surface of the water, to know what they eat analyzes alimentary canal. Thus the present work tries to determine the trofhic plot of the fish of the San Miguel dam Arc. The fish of the dam with a small boat of 30 meters in length captured themselves and 1/3 of inch, the organisms paid attention with formalin to 10 %, the fish were identified like the food that consumed, with specialized keys, to the abundance of the nutritional groups I am applied the index to them of Simpson. One was that Chirostoma humboldtianum, is zooplanctofago specialistic, Cyprinus carpio, and Carassius auratus is planctofagos generalist and Poeciliopsis infans is planctófago specialistic. The trofic plot is based on zooplancton (Bosmina and Mastigodiaptomus) in addition to zoobentos (Corixidae).

The species of aquatic hemiptera in the piscicole ponds GL and JC of Soyaniquilpan de Juárez, Estado de México are analyzed during October of 1995 to August 1996. Were recorded environmental parameters in the two systems as well as the abundance and diversity of hemiptera. The GL pond presented eight species: Buenoa uhleri Truxal, 1953; B. margaritacea Bueno, 1908; Trichocorixella mexicana Hungerford, 1927; Notonecta shooterii Uhler, 1849; Krizousacorixa femorata Guerín, 1857; Graptocorixa abdominalis (Say), 1832; N. undulata Say, 1832 and Corisella edulis (Champion), 1901 and seven in JC pond: T. mexicana, B. margaritacea, G. abdominalis, N. shooterii, K. femorata, B. uhleri and C. edulis.The diversity was major in GL pond and minor in JC pond. The PCA remarks to the conductivity, depth, oxygen and pH in GL pond (84.3 % of variability), and JC pond the conductivity, transparence and pH were the most important (83.5 %). Is concluded that the enviromental variations registered in two systems are not considerables, but their influence on the diversity and abundance are notably as well as the environmental heterogeneity of the two systems.

The photosynthesis type C4 had its origin 7-5 millions years ago in several genera of plants. The atmospheric diminution of CO2 concentration leads to a concentrative mechanism. Some studies of genes and enzymes than participate in this pathway shown several changes than have occurred in DNA and proteins in order to adapt them for a new function, CO2 concentrating mechanism. This mechanism avoid Rubisco‘s oxygenase function.

In this work is analyzed how a deer feeds from shrubs or how a mice feeds from seeds. Both practice a form of predation named herbivory. The fact is that to feed on plants has consequences on survival, both on plants and herbivores. The removal of plant tissues, bark, stems and sap influences the capacity of the plant to survive, despite not all of it is consumed. Also is studied that despite a plant cannot escape from their herbivore enemies, it can defend itself chemically. Many plants attract, resist or inhibit to other organisms producing special chemical substances, known as secondary metabolites. Also is pointed out that the primary products are substances such as proteins, carbohydrates, and lipids, all produced and utilized by the living organisms. However, plants can have so many differences in their secondary products, as in their external aspect.

In the following study four properties of sixteen different types of woods from the seasonally dry tropical forest were analyzed with the purpose of determining if they are useful in the manufacturing of particleboards and fiberboards. The woods analyzed were: Myrcianthes fragrans, Phoebe tampicensis, Casimiroa pringley, Acacia berlandieri, Drypetes lateriflora, Esenbeckia berlandieri, Lysiloma divaricata, Robinsella discolor, Sapindus saponaria, Harpalyce arborescens, Wimmeria concolor, Krugiodendrom ferreum, Ebanopsis ebano, Pithecellobium pallens, Zanthoxylum fagara y Cordia boissieri. The fiber’s properties analyzed were the longitude, longitude-diameter relation known as Peteri coefficient, basic density, pH and the razon de compression which is necessary to manufacture medium density particleboards and hardboards. The fiber from the analyzed woods had a longitude rank of 653 to 1229 μ, a Peteri coefficient rank of 43.14 to 82.45, a pH rank of 5.06 to 7.64 and a basic density rank of 0.56 to 0.97 g·cm-³. Due to this values and its analysis, eleven types of woods individually were considered useful for the manufacture of medium density particleboards. If the woods are mixed then twelve species can be useful for the manufacture. All types of woods can be used to manufacture hardboards and extra hardboards.