the effects of lead on the proline content and dry weight of leaves and roots were investigated in two canola cultivars (brassica napus l.) grown in the hoagland solution. the growth of treated plants was inhibited under lead stress. lead induced differential accumulation of proline in canola grown in solution with the addition of 0, 100 and 200 mgl-1 of pb. hyola308 cultivar showed low biomass...

The Progressive Nitrogen Limitation (PNL) hypothesis suggests that ecosystems in a CO2-enriched atmosphere will sequester C and N in long-lived biomass and soil organic pools, thereby limiting available N and constraining the continued response of net primary productivity to elevated [CO2]. Here, we present a six-year record of N dynamics of a sweetgum (Liquidambar styraciflua) stand exposed to...

Functional trait plasticity is a major component of plant adjustment to environmental stresses. Here, we explore how multiple local environmental gradients in resources required by plants (light, water, and nutrients) and soil disturbance together influence the direction and amplitude of intraspecific changes in leaf and fine root traits that facilitate capture of these resources. We measured p...

Aeroponic culture is an alternative method for optimizing growth of different plants in controlled conditions. Aeroponic systems are an efficient tool for the root studies and improving medicinal root production. In order to study the feasibility of valerian (Valeriana officinalis L.) production in aeroponic systems and assessing the effects of different NAA concentrations (0, 0.1, 0.3, and 0.5...

in order to evaluate the inter-specific hybrid p. atlantica × p. vera cv. ‘badami- riz- zarand’ to drought stress, a factorial experiement was conducted as based on a completely randomized design of three irrigation intervals 3, 6 and 9 days on qazvini, badami-riz-zarand and the hybrid of p. atlantica × p. vera cv. badami- riz-zarand rootstocks of pistachio. results indicated that such physiolo...

BACKGROUND AND AIMS Studies on the effects of sub- and/or supraoptimal temperatures on growth and phosphorus (P) nutrition of perennial herbaceous species at growth-limiting P availability are few, and the impacts of temperature on rhizosphere carboxylate dynamics are not known for any species. METHODS The effect of three day/night temperature regimes (low, 20/13 °C; medium, 27/20 °C; and hig...

We formulate a dynamic evolutionary optimization problem to predict the optimal pattern by which carbon (C) and nitrogen (N) are co-allocated to fine-root, leaf, and wood production, with the objective of maximizing height growth rate, year by year, in an even-aged stand. Height growth is maximized with respect to two adaptive traits, leaf N concentration and the ratio of fine-root mass to sapw...

drought tolerance of three own-rooted grape cultivars (rashe, ghezil uzum and red sultanina) was evaluated at four different levels of soil moisture contents (40, 60, 80 and 100% field capacity through a factorial experiment based on a randomized complete block design with three replications for a duration of 3 months. results revealed that, grape cultivars, levels of soil moisture and the inte...

We measured the level of xylem-derived cytokinins (CKs) entering a cotton leaf, and the CK levels in the same leaf, thus enabling xylem sap and foliar CKs to be compared concurrently. Although zeatin was the dominant CK in xylem sap, zeatin, dihydrozeatin, and N(6)-(2-isopentenyl) adenine were present in approximately equimolar levels in leaves. Elevated [CO(2)] (EC) has an effect on the levels...