Reproduccion asexual de los estacas were prepared in 2 different seasons wet and dry and treated with different Reproduccion asexual de los estacas conditions and auxin concentrations IBA and NAA. Hardwood and softwood cuttings of B. However, high hormone concentrations favored number, length of roots and number of developed shoots.
Natural regeneration of these species is limited and the species are difficult to propagate from seeds. Vegetative propagation of these species could be an alternative to get clonal planting stock for reforestation programs in some Mexico City areas. Las estacas de madera lignificadas y madera suave de B. Exotic species have long been used for reforestation, Reproduccion asexual de los estacas in many cases such species have produced undesirable ecological effects, because they can become invasive plants D'Antonio and Meyerson, However, since there is a lack of studies about most native species, it is necessary to increase our knowledge about plant propagation from seeds or cuttings to introduce them to the ecosystem instead of exotic plants.
Because the first life stages are crucial for the establishment showing a high seedling mortality, it is very important to improve the use of native species vegetatively propagated, which have the advantage of avoiding these critical Reproduccion asexual de los estacas Weber and Stoney, ; Arriaga
Reproduccion asexual de los estacas
Reproduccion asexual de los estacas. Due to urban development its surface has been drastically reduced in spite of its importance as a recharge area for the basin aquifers Ezcurra
Reproduccion asexual de los estacas al.
Although some of the originally reported species are no longer found, new species to the reserve have been reported, due to introduction of propagules in soil from other sites. Local extinction of taxa is associated with urbanization and illegal extraction of ornamental species. One of the most conspicuous and Reproduccion asexual de los estacas species in the reserve was Senecio praecox, an endemic species to the Pedregal, for this reason the vegetation Reproduccion asexual de los estacas the Pedregal was called Senecionetum praecoxis by Rzedowski However, its abundance has been reduced due to competition with other species.
This change could be due to the low seed germination of S. In this way, Buddleja cordata, Dodonaea viscosa, Senecio praecox, and other Pedregal species could be reintroduced into the PSAR and other areas, at the same time this approach could improve the for the establishment of the same and other plant species Arriaga et al.
This strategy could be used in the first steps of restoration programs, followed by the substitution of the vegetatively propagated individuals by saplings to avoid the reduction of genetic variability linked to vegetative propagation.
Dodonaea viscosa, is an evergreen species growing in forest gaps, ravines and in altered land with irregular surface. It has also been considered a good species for Reproduccion asexual de los estacas due Reproduccion asexual de los estacas its resistance to water deficit Degollado, Senecio praecox, a deciduous shrub or tree, is greatly appreciated for its landscape value due to its conspicuous flowers, which appear during the dry season.
These species are all native to, and dominant in, the
Reproduccion asexual de los estacas. Additionally, plants in the urban environment play an important role by mitigating extreme microclimates, collecting dust and
Reproduccion asexual de los estacas from Reproduccion asexual de los estacas air, and contributing to the recharge of aquifers Sanders, ; McPherson and Nowak, ; Barradas et al.
Therefore, these species, mainly S. We also determined optimum hormone types and concentrations to root the cuts of the studied species, which can be used as a basis for other studies.
The Reserve's substrate is basaltic, and its topography very irregular Rzedowski, Mean annual temperature is Although some of the originally reported species are no longer found, new species have been reported, due to introduction of propagules in soil from other sites, and the probable diaspore dispersion from oak forests. Species studied, and selected donor plants. Three plant species growing in the PSAR were selected for this study: Loganiaceae, Dodonaea viscosa Jacq.
Sapindaceae, and Senecio praecox D. The donor individuals from each species were selected from areas outside the Reserve but with similar vegetation and environment, along the central road dividers, sidewalks, gardens and streets of the UNAM Campus. Only those individuals that looked anatomically and morphologically healthy and vigorous were selected.
Sixty individuals of each species were chosen and numbered according to their location in the area. These individuals were used to obtain the stem cuttings for all treatments.
They were then labeled and placed in moist paper bags. Foliose softwood cuttings were made from lateral branches at 2 m from the soil surface.
Leaves of cuttings were cut when there were more than 5 leaves in order to reduce evaporation. Cuttings were hormone treated and sown
Reproduccion asexual de los estacas after cutting. The hormones used were: Pure IBA was placed in ml of alcohol and diluted with distilled water Reproduccion asexual de los estacas get the concentrations Reproduccion asexual de los estacas for each treatment, then cuttings were exposed to IBA immersing the tip in 4 ml of solution, Reproduccion asexual los estacas the control group Reproduccion asexual de los estacas ml of distilled water was used.
The cuttings were treated by IBA placing the base of the in the aqueous solution for 24 hours or in distilled water for the control; they were then placed on the substrate prepared before the cuttings had been cut.
The cuttings with commercial IBA Radix and NAA Rootone in talc were placed inside damp paper bags to be placed on the substrate at the same time as the other cuttings. The substrate consisted of a mixture of peat and agrolite in a 1: The cuttings were individually set in the substrate at approximately 10 cm deep, watered with a very fine sprayer and placed on shelves in a nursery.
They were watered near to field capacity and checked every third day. After 5 months, the cuttings were removed
Reproduccion asexual de los estacas the bags and assessed for: Hormone treatments were combined with 4 experiments as shown in 1. The objective of the first 2 was to test the rooting capability of cuttings from hardwood stems collected during the wet and dry seasons and placed in a nursery.
For each kind of cut, the propagation place was established according to Longman and Wilson and Hartmann et al. Experimental design was for the first and second experiments: The third Reproduccion asexual de los estacas design was 4 pure IBA concentrations x 2 commercial IBA concentrations x 2 temperatures x 4 replicates x 30 Reproduccion asexual de los estacas and 4 pure IBA concentrations x 2 commercial IBA concentrations x 1 NAA concentration x 2 temperatures x 4 replicates x 10 cuttings for the fourth experiment.
Control for each experiment was 2 temperatures x 4 replicates x 30 cuttings. The probability of Reproduccion asexual de los estacas was calculated by logistic regression analysis using JMP ver.
The use of different hormonal concentrations of IBA or the use of commercial products Radix and NAA induced significant differences in cuts rooting. The effect of each one of them depended on the species and the experiment. All cuts of all the species that rooted Reproduccion asexual de los estacas. The high length and number of roots were reached in experiments 1 and 4. For the number of roots, Reproduccion asexual de los estacas best result was obtained in the fourth experiment with IBA ppm, but this result did not differ significantly from others Figs.
In the fourth experiment Buddleja cordata produced mainly buds which showed a very low rooting. Reproduccion asexual de los estacas best hormonal treatment was IBA 10 and 1 ppm Fig. In the first experiment produced with IBA ppm a low number of buds in relation to the buds produced in several treatments in the fourth experiment Fig. The rooting process in the 3 species showed considerable variation in the different experiments, and the rooting percentage of the species depended on species, season or month of collection and hormone
Reproduccion asexual de los estacas.
Nevertheless, variables that are related to the health of the rooted cut as number and length of these and production of buds de Andres et al. In spite of the reduced rooting probability 0. Because number of roots and root length indicate the cutting ability to assimilate nutrients, survive in the soil, have structural support,
Reproduccion asexual de los estacas develop buds to ensure the future CO 2 Reproduccion asexual de los estacas of the plant, these also indicate the acclimatization for future planting, which may increase survival in reforestation efforts de Andres et al.
Soft leafy cuttings as well as the collection season, adequate for B. It is possible that the low rooting capacity of B. It has been reported for hardwood species that the use of cuttings from juvenile plants is more appropriate than the use of the low lignified soft cuts from mature plants Swamy et al. The soft cuts were collected in the wet season, but in the future it Reproduccion asexual de los estacas be necessary to take into account that the season of the year is relevant to the physiological condition of plants, therefore it could be necessary to harvest Reproduccion asexual de los estacas soft cuts when lignification has started as had been suggested by Stankova and Panetsos This has been related to the hormonal and nutritional stage of plants, which ought to be adequate to produce new structures Hartmann et al.
In contrast with the other 2 species, the non woody S. Soft cuttings also had high rooting probabilities, but lower than hard cuttings experiment 3.
This occurs in some woody species, where a slight lignification is required for rooting Stankova and Panetsos, as occurs in the mature tissues of S. Further, the stems of S. This is common among succulent plants Baldini, Low IBA concentrations 10 and ppm or Radix induce high rooting and good cutting health, which is Reproduccion asexual de los estacas from the commercial point of view. This is considered a low tech system suitable for rural areas McDick et al.
Differing from the latter, D. Vegetative propagation of trees from the 3 studied species can improve restoration programs in the southern portion of Mexico City and other areas. Vegetative propagation is recommended to avoid the high mortality of seedlings and saplings and increase the success of restoration programs Zahawi, ; Negative aspects of the use of vegetatively propagated plants can be overcome by using a large number of plant Reproduccion asexual de los estacas to increase genetic variability and by using these plants only for the first steps before using those propagated from seeds.
Rooting capacity varied according to species and collection season. The rooting capability in B. Variability in propagation potentials of stem cuttings of different physiological ages of Gongronema latifolia Benth. World Journal of Agricultural Sciences 3: Energy balance and transpiration
Reproduccion asexual de los estacas an urban tree hedgerow in Mexico City.
Stomatal conductance in a tropical xerophilous shrubland at a lava substratum.
Reproduccion asexual de los estacas Journal of Biometeorology Loganiaceae y Verbesina virgata Cav. Compositae del Pedregal de San Angel. Exotic Reproduccion asexual de los estacas species as problem and solutions in ecological restoration: Vegetative propagation of Colutea arborescens L. Vegetative propagation of Colutea istria Mill. The basin of Mexico. United Nations University Press.
Characterizing individual particles on tree leaves using computer automated scanning electron microscopy. Advances in Environmental Research 2: Physiology of vegetative reproduction.