Urtica dioica L. is an Iranian native pharmacological plant for which little attention has been paid to the anatomical structure. Medical applications of this plant include diabetes therapy, digestive improvement, anemia and kidney disease therapy. Because climatic conditions can affect the anatomical structure which in turn affects pharmacological compositions, research on the anatomy of this ...

This paper assesses the resilience of Alaska’s boreal forest system to rapid climatic change. Recent warming is associated with reduced growth of dominant tree species, plant disease and insect outbreaks, warming and thawing of permafrost, drying of lakes, increased wildfire extent, increased postfire recruitment of deciduous trees, and reduced safety of hunters traveling on river ice. These ch...

We examine how induced plant defences affect the evolution of resistance in herbivores (i.e. the ability to overcome plant defences) compared with constitutive defence strategies. Since resistance of herbivores may evolve as a result of major monogenic and/or quantitative (polygenic or gene amplification) genetic sources, and the selective pressure imposed by plant defences affects the rate of ...

A profusion of fruit forms implies that seed dispersal plays a central role in plant ecology, yet the chance that an individual seed will ultimately produce a reproductive adult is low to infinitesimal. Extremely high variance in survival implies that variations in fruit production or transitions from seed to seedling will contribute little to population growth. The hey issue is that variance i...

Explaining variation in population growth rates is fundamental to predicting population dynamics and population responses to environmental change. In this study, we used matrix population models, which link birth, growth and survival to population growth rate, to examine how and why population growth rates vary within and among 50 terrestrial plant species. Population growth rates were more sim...

Pre-dispersal seed predators are often chosen as biocontrol agents because of their high impacts on plant fitness; however, they have a mixed record in realizing decreased plant population growth. Few studies have experimentally removed agents to explore their impact on weed population growth. Here, we used manipulative experiments with invasive yellow starthistle (YST), Centaurea solstitialis,...

Objective: Taro (Colocasia esculenta L. Schott) is a perennial root crop that belongs to Araceace family.  It is widely cultivated as a staple food in Africa, Asia and pacific Islands. Despite its importance, there is limited information on many aspects of the crop. In order to obtain data that can support improved and sustainable taro production, a field trial was conducted to study t...

Sap-feeding insects such as aphids are the only insect herbivores that show positive responses to elevated CO2. Recent models predict that increased nitrogen will increase aphid population size under elevated CO2, but few experiments have tested this idea empirically. To determine whether soil nitrogen (N) availability modifies aphid responses to elevated CO2, we tested the performance of Macro...