The acclimation responses of walnut leaf photosynthesis to the irradiance microclimate were investigated by characterizing the photosynthetic properties of the leaves sampled on young trees (Juglans nigraxregia) grown in simulated sun and shade environments, and within a mature walnut tree crown (Juglans regia) in the field. In the young trees, the CO(2) compensation point in the absence of mit...

Spectral shade ratios, defined as the ratios of the spectral irradiances on horizontal and sun normal planes in the tree shade to those on a horizontal plane in sunlight, were calculated. These planes were in the shade of an isolated medium canopy density tree and a sparse canopy density tree at the tree shade sites of the centre, edge and trunk. The sun normal plane was employed as there are s...

leaf N concentration and content, and relative leaf absorbance (αr) were measured in 1-year-old seedlings of shade-intolerant Betula papyrifera Marsh., moderately shade-tolerant Quercus rubra L. and shade-tolerant Acer rubrum L. Seedlings were grown in full sun or 26% of full sun (shade) and in ambient (350 ppm) or elevated (714 ppm) CO2 for 80 days. In the shade treatments, 80% of the daily PP...

The spectral shade ratios defined as the ratios of the spectral irradiances on horizontal and sun normal planes in the tree shade to those on a horizontal plane in sunlight were calculated. These planes were in the shade of an isolated medium canopy density tree and a sparse canopy density tree at the tree shade sites of the centre, edge and trunk. The sun normal plane was employed as there are...

Background/Purpose: This paper has considered the erythemal UV (UVery), UVA and visible irradiances in the shade of Australian trees for each season at a sub-tropical southern hemisphere site. Methods: The irradiances in tree shade have been measured with radiometers as a percentage of the irradiances in the sun for each season of the year. Results: Although the solar irradiances are lower in w...

Different drying methods viz., Sun drying, shade drying and tray drying (temperature 45, 55 and 65 0C) were used for dehydration of curry (Murraya koenigii) leaves for optimal retention of color and its constituents. It was observed that the time required for tray drying was less (27%), when compared to sun and shade drying. Tray dried (550C) curry leaves had maintained nutritional constituents...

The solar spectral UVR irradiances in tree shade and sunlight have been measured in a sub-tropical southern hemisphere summer. The spectral data allowed the UVB and UVA irradiances and the biologically effective irradiances to be calculated for different harmful biological processes to human skin and eyes. The average of the ratio of the UVA to UVB irradiances was lower by 26% in the shade comp...

The differential pigment composition and photosynthetic activity of sun and shade leaves of deciduous (Acer pseudoplatanus, Fagus sylvatica, Tilia cordata) and coniferous (Abies alba) trees was comparatively determined by studying the photosynthetic rates via CO(2) measurements and also by imaging the Chl fluorescence decrease ratio (R(Fd)), which is an in vivo indicator of the net CO(2) assimi...

Tonnage (T), Simmonds (S) avocado trees, and TxS crosses were evaluated for differences in chlorophyll content and maximal quantum yield of photosystem II in sun and shade-type leaves. Total chlorophyll content by area (Chl a+bar) ranged from 984 mg m in TxS240 to 4320 mg m in Simmonds. Chlorophyll a/b ratio (Chl a/b) ranged from 9.8 to 5.5 in TxS238 and TxS243, respectively. Tonnage and Simmon...