The ability of invasive plants to achieve higher relative growth rates (RGR) than their native counterparts has been widely documented. However, the mechanisms allowing invasives to achieve higher RGR are poorly understood. The objective of this study was to determine the basis for RGR differences between native and invasive forbs that have widely invaded nutrient-poor soils of the Intermountai...

Leaf area index (LAI) is a key structural characteristic of forest ecosystems because of the role of green leaves in controlling many biological and physical processes in plant canopies. Accurate LA1 estimates are required in studies of ecophysiology, atmosphere-ecosystem interactions, and global change. The objective of this paper is to evaluate LA1 values obtained by several research teams us...

BACKGROUND AND AIMS Corner's rule states that thicker twigs bear larger leaves. The exact nature of this relationship and why it should occur has been the subject of numerous studies. It is obvious that thicker twigs should support greater total leaf area ([Formula: see text]) for hydraulical and mechanical reasons. But it is not obvious why mean leaf size ([Formula: see text]) should scale pos...

for comparison the growth characteristics and quantitative and qualitative yield of two summer savory species (such as satureja khuzestanica and s. rechingeri) in response to rainfed and irrigated conditions, an experiment was carried out on the basis of split-plot design in completely randomized block design with three replicates in north of khuzestan during growing season of 2012-2013. irriga...

Rainfall and temperature are the primary limiting factors for optimum quality and yield of cultivated jujube (Ziziphus jujuba Mill.). Adaptation to arid and cool environments has been and remains an important goal of many jujube improvement programs. This study summarized the survey results of 116 Chinese jujube varieties grown at 33 sites in China. The objective was to identify the environment...

Leaf longevity determines the annual cost of replacing foliage biomass and influences water and nutrient budgets. Longevity is readily estimated in most evergreen species by annual bud scars along the shoot. However, some species with indeterminate growth do not show these annual markers, making estimation of longevity difficult. One of these species is the widespread and economically valuable ...

T h e PROSPECT leaf optical properties and SAIL canopy reflectance models were coupled and inverted using a set of 96 AVIRIS (Airborne Visible~Infrared Imaging Spectrometer) equivalent spectra gathered in afield experiment on sugar beet plots expressing a large range in leaf area index, chlorophyll concentration, and soil color. In a first attempt, the model accurately reproduced the spectral r...

cotton whitefly,  bemisia tabaci is considered as one of the most important pests of fall cucumber in khouzestan province. studies were conducted to examine the seasonal dynamics and spatial distribution of b.tabaci on fall cucumber during 2006 and 2007 in mollasani area. in both years, adult whiteflies first appeared on the plants in early september. in 2006 and 2007, mean maximum of adults oc...

A major component in a crop growth model is leaf area development, which has a major influence on photosynthesis and transpiration. The knowledge about the leaf area development of wheat especially in high temperature environments is incomplete. The aim of this study was to quantify leaf production and senescence of 15 spring wheat cultivars. Field experiments were conducted at the research far...

In this research, to evaluate the effect of superabsorbent polymer and drought stress on the number and leaf area of Lettuce, experimental  research was conducted in a completely randomized design factorial with two treatments of irrigation regime at three levels (60, 80 and 100 percent of crop water requirement) and four superabsorbent hydrogel application (0, 4, 6 and 8 g per kg of soil) in t...