Rattan spines as deterrence? A spinescence study on different species of rattans

Rattan spines are most often regarded as an identification trait and perhaps as a physical protection structure. In this study, we study the spinescence traits from five different species rattan: Daemonorops lewisiana, Daemonorops geniculata, Calamus castaneus, Plectomia griffithii, and Korthalsia scortechinii. We tested length, width, angle, strength, spine density, cross-section surface, spine color, and leaf trichomes (only for D. lewisiana, C. castaneus and D. geniculata). We also tested whether the spines were capable of deterring small climbing mammals (for Plectomia griffithii and Calamus castaneus) by using a choice selection experiment. Due to a variety of spine traits, we could not categorize whether any species is more or less spinescent than the others. We suggest that spines have a much more significant role than merely as a physical defense and work together with other rattan characteristics. This is also evidenced by our choice selection experiment, in which the spines on a single stem donot deter small climbing mammals. However, this is a work in progress, and we have outlined several alternative methods to be used in future work.

Morphological response of a cactus to cement dust pollution

Cement dust from cement plants around the world has multiple negative effects on organisms and their environment. Cement's effects come from its strongly alkaline nature and high content of heavy metals. Previous studies on plants have documented that cement dust deposition can influence plant vegetative growth, the lipid and ionic composition of tissues, and foliar temperature. Here we evaluate the effects of cement dust coming from a plant in western Argentina on the morphology of the cactus Tephrocactus aoracanthus. In sites located at 0.15km, 2km and 6km from the cement plant, we recorded five morphological attributes of the cactus: length and number of spines, cladode (stem) diameter, and fresh and dry weight. We also transplanted plants in situ to evaluate the effect of distance from the cement plant. In addition, we set an experiment spreading cement dust weekly on the aerial and ground parts of the cactus. Results of our field observational and experimental studies indicate that cement dust deposition on aerial parts of the plant leads to increased spine length, number of spines, and wet and dry weights of cladodes.