Citrus tristeza is one of the most destructive diseases of citrus and its causing agent CTV was introduced from Japan to northern Iran in the late 1960s. After about three decades of restriction to originally infected Satsuma trees, natural spread of CTV has being undertaken and melon aphid (Aphis gossypii Glov.) was confirmed as a potent vector in these areas. Regarding the specificity of aphi...

Woody perennials subjected to root oxygen-stress often respond with varying levels of reduced assimilation and leaf gas exchange. Yet in most of these studies, seedlings grown in pots were subjected to experimental conditions that rarely exist in nature for mature trees. To determine if flooding mature orchard-grown pecan (Carya illinoiensis (Wangh) K. Koch) results in a similar depressed photo...

in order to investigate the effects of cold stress on antioxidant enzymes and physiological characteristics in chickpea, two separate experiments were conducted at germination and seedling stages. each experiment with six temperature levels (t1(control)=15c°, t2=5c°, t3=0c°, t4=-5c°, t5=-10c° and t6=-15c°) and three varieties (v1=pirouz v2=ilc482 v3=bivaniej) was carried out in a randomized com...

Seed production, seed dispersal and recruitment are critical processes in population dynamics, because they are almost never completely successful. We recorded the recruitment dynamics for the population of Dipteryx oleifera in a tropical rainforest in eastern Nicaragua (12 degrees 05' N., 83 degrees 55' W.) from March 2002 to August 2006. Seeds and seedlings had highly clumped distributions, w...

Ectomycorrhizal (ECM) fungal mycelia are the main organs for nutrient uptake in many woody plants, and often connect seedlings to mature trees. While it is known that resources are shared among connected plants via common mycorrhizal networks (CMNs), the net effects of CMNs on seedling performance in the field are almost unknown. CMNs of individual ECM fungal species were produced in an early s...

Many large-seeded Neotropical trees depend on a limited guild of animals for seed dispersal. Fragmented landscapes reduce animal abundance and movement, limiting seed dispersal between distant forest remnants. In 2006, experimental plantings were established in pasture to determine whether plantings enhance seed dispersal and, ultimately, seedling recruitment. We examined patterns of naturally ...

Since its introduction into the Southern Appalachians in the 1950s, the balsam woolly adelgid, Adelges piceae Ratzeburg (Hemiptera: Adelgidae), has devastated native populations of Fraser fir, Abies fraseri (Pursh) Poir. (Pinales: Pinaceae), and has become a major pest in Christmas tree plantations requiring expensive chemical treatments. Adelges piceae-resistant Fraser fir trees would lessen c...