UNDERSTANDING TRADITIONS AND PRACTICES OF MEDICINAL PLANT USE IN CARHUAMAYO, JUNIN, PERU

Understanding and preserving Traditional Ecological Knowledge and Practices (TEKP) are essential for the continued resilience and cultural diversity of humanity. TEKP faces a multitude of threats from habitat loss, growth of the market economy, globalization, and acculturation. Medicinal plant use in the high Andean town of Carhuamayo, Junín, was studied to assess the vibrancy of that particular branch of TEKP in that area, in what parts of the population it was held, and what factors influence its loss or growth. Gender, age, migrant status, and acculturation levels were not found to be statistically significant in predicting medicinal plant knowledge. Analysis through a livelihoods lens further demonstrated that gender was not a significant determinant of medicinal plant knowledge and those whose livings depend on natural resource use may be more knowledgeable. The uniformity of ethnobotanical knowledge in Carhuamayo was attributed to the unified nature of the community through many organized groups and widespread sharing of knowledge. The uniformity of medicinal plant knowledge may also reflect the loss of TEKP over many generations. Factors that may have resulted in the erosion of local TEKP could be historical colonial forces and terrorism, migration, application of agrochemicals, pollution from mining and other sources devastating biodiversity, and climate change

Plant responses to photoperiod

Photoperiod controls many developmental responses in animals, plants and even fungi. The response to photoperiod has evolved because daylength is a reliable indicator of the time of year, enabling developmental events to be scheduled to coincide with particular environmental conditions. Much progress has been made towards understanding the molecular mechanisms involved in the response to photoperiod in plants. These mechanisms include the detection of the light signal in the leaves, the entrainment of circadian rhythms, and the production of a mobile signal which is transmitted throughout the plant. Flowering, tuberization and bud set are just a few of the many different responses in plants that are under photoperiodic control. Comparison of what is known of the molecular mechanisms controlling these responses shows that, whilst common components exist, significant differences in the regulatory mechanisms have evolved between these responses

Leaf architecture, lignification, and tensile strength during vegetative phase change in Zea Mays.

Background and Aims: Leaf morphology, anatomy, degree of lignification, and tensile strength were studied during vegetative phase change in an inbred line of Zea mays (OH43 x W23) to determine factors that influence mechanical properties during development. Methods: Tensometer, light microscopy, histochemistry. Key results: Mature leaf length increased linearly with plant development, peaked at leaves 7 and 8 (corresponding to the onset of the adult phase) and then declined. Leaf width was stable for leaves 1 through 3, increased to leaf 7, remained stable to leaf 10, and then declined through leaf 13. Lamina thickness was highest for leaf 1 and decreased throughout development. Leaf failure load to width ratio and failure load to thickness ratio increased with development suggesting that changes in leaf morphology during development do not entirely account for increases in failure load. Histochemical analyses revealed that leaf tensile strength correlates with percent lignification and the onset of anatomical adult features at various developmental stages. Conclusions: These data demonstrate that in Zea mays lignification of the midrib parenchyma and epidermis may be directly correlated with increased tensile strength associated with phase change from juvenility to adulthood. Failure load and resultant tensile strength values are primarily determined by the percent tissue lignification and the appearance of leaf architectural characters that are associated with the transition from the juvenile to the adult phase. Increased mechanical stability that occurs during the phase transition from juvenility to adulthood may signify a fundamental change in strategy for an individual plant from rapid growth (survival) to reproduction

Allometric growth of Xanthium (Compositae) leaves

When Xanthium lamina width is plotted versus leaf length during the entire period of growth, a straight line is obtained representing an allometric relationship with a regression correlation coefficient of 0.9973 a lamina width to length ratio of 0.502 ± 0.01 and chordate morphology. On the other hand, gibberellic acid treated plants yield a correlation coefficient of 0.9871 a lamina width to length ratio of 0.372 ± 0.0074 and lanceolate leaves. The fraction of leaf width to leaf length is a measure of lamina width reduction. Gibberellic acid alters the mechanism which controls the balance between the leaf length and the leaf width

The early phase change Gene in Maize

Recessive mutations of the early phase change (epc) gene in maize affect several aspects of plant development. These mutations were identified initially because of their striking effect on vegetative phase change. In certain genetic backgrounds, epc mutations reduce the duration of the juvenile vegetative phase of development and cause early flowering, but they have little or no effect on the number of adult leaves. Except for a transient delay in leaf production during germination, mutant plants initiate leaves at a normal rate both during and after embryogenesis. Thus, the early flowering phenotype of epc mutations is explained completely by their effect on the expression of the juvenile phase. The observation that epc mutations block the rejuvenation of leaf primordia in excised shoot apices supports the conclusion that epc is required for the expression of juvenile traits. This phenotype suggests that epc functions normally to promote the expression of the juvenile phase of shoot development and to suppress the expression of the adult phase and that floral induction is initiated by the transition to the adult phase. epc mutations are epistatic to the gibberellin-deficient mutation dwarf1 and interact additively with the dominant gain-of-function mutations Teopod1, Teopod2, and Teopod3. Genetic backgrounds that enhance the mutant phenotype of epc demonstrate that, in addition to its role in phase change, epc is required for the maintenance of the shoot apical meristem, leaf initiation, and root initiation