Rubber tree and cassava: Biological features, practical use, ethnocultural traditions

Aim. To make a review of Hevea and Manihot, two related plant genera that have been used by humans for a long time, to analyze their biological features, to give information on their use, to present the most interesting materials associated with them. Main part. A review of Hevea and Manihot, useful plants in the tropics and subtropics, is carried out. Their characteristics are given, biological features are considered, and data on the places of origin, on the regions where they are cultivated are considered. Information on their use by people is presented: Hevea as a rubber-bearing, cassava as a food product. Special attention is paid to the cytogenetic features of Hevea and Manihot, information about the ancient polyploid origin of these plants. Conclusion. From ancient to the present time, mankind has been using in everyday life many valuable species of subtropical and tropical plants, including Hevea and Manihot, which are an integral part of ethnocultural traditions.

In Vitro Screening of Plant Materials to Reduce Ruminal Protozoal Population and Mitigate Ammonia and Methane Emissions

Alternative feed sources can be utilized to reduce enteric methane (CH4) emissions, a major greenhouse gas that contributes to global warming. This study aimed to evaluate the potential use of tropical plants to improve digestibility, reduce protozoal populations, improve rumen fermentation, and minimize methane emissions from ruminants. The plants considered herein grow in tropical climates, are easily accessible in large quantities, and are directly related to human food production. Nine plants that grow naturally in tropical climates were assessed. Plant supplementation substantially enhanced accumulative gas production at 24 h (p < 0.05). The apparent organic matter digestibility (AOMDvt) of the diet was not affected by five of the nine plants. With the addition of the plant material, ammonia nitrogen concentrations were reduced by up to 47% and methane concentrations were reduced by 54%. Five of the nine plant materials reduced methane production in terms of CH4/dry matter and CH4/digestibility of the organic matter by 15–35% and 8–24%, respectively. In conclusion, supplementation with plants with high tannin contents was shown to be a viable strategy for improving rumen fermentation, reducing protozoal populations, and limiting methane emissions. In this regard, the leaves of Piper sarmentosum, Acmella oleracea, Careya arborea, and Anacardium occidentale were especially promising.

How Do Soil Resources Affect Herbivory in Tropical Plants Along Environmental Gradients? A Test Using Contrasting Congeneric Species

Plants adapted to different habitats exhibit differences in functional traits and these characteristics are influenced by soil properties. We tested the hypothesis that soil resource availability influences the functional traits of plants, affecting therefore herbivory levels. We examined three Byrsonima plant species with different life forms that occurred across a distinct edaphic habitat along the Doce River Basin, South-eastern Brazil. We characterize habitats according to soil nutrient concentration and measured functional characteristics of crown architecture, leaf nutrients, sclerophylly, leaf area and leaf density. In addition, we evaluated how these variables influenced herbivory levels of congeneric plants. Our data have shown that species along a gradient of soil nutrients have functional characteristics influenced by habitat, which in turn affected herbivory levels. By comparing species from different life forms but within the same genus along a stress-gradient of continuous habitats, we described a corresponding gradient of plant functional traits and tissue consumption by herbivorous insects.