1. Populations of Metrosideros polymorpha establish across a broad range of precipitation in Hawai‘i – from <400 to >10000 mm per year. To determine whether adjustment of hydraulic and photosynthetic traits could contribute to this success in both high and low rainfall, we sampled populations on the wet and the dry sides of Hawai‘i Island, replicated on two different-aged lava flows at similar ...

The distribution of glycine decarboxylase (GDC) in leaves of pea (Pisum sativum L.) and wheat (Triticum aestivum L.) has been investigated using immunogold labeling of the P-protein subunit of the GDC complex. Mitochondria in photosynthetic mesophyll cells were densely labeled, whereas those in nonphotosynthetic vascular parenchyma and epidermal cells were only weakly labeled. In pea leaves the...

This paper discusses the differences and similarities of object-oriented programming systems and frame systems, and advocates the amalgamation of these two kinds of systems. A frame system called BEEF is introduced. It provides, in addition to frame system characteristics, the basic functionality and ease of use of an object-oriented extension of Common Lisp, making it well suited for knowledge...

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...

We have recently identified cytokinin as an important xylem-carried signal involved in the photosynthetic acclimation of plants to light gradients in dense canopies. Lower leaves become shaded in a dense canopy and consequently have reduced transpiration rates. our measurements have shown that this results in a reduced delivery of cytokinins carried in the transpiration stream to shaded leaves,...

The virescent cotton (Gossypium hirsutum) mutant described here differs from normal cultivated cotton by a single mutation in the nucleus. The mutant exhibits nuclear control of chlorophyll and carotenoid development. Young leaves are distinctly yellow and become green with age. There is no unusual photometabolism of (14)CO(2) or (14)C-acetate in this mutant. It is probable that the nuclear vir...

Variations in leaf photosynthetic, morphological and biochemical properties with increasing plant height from seedlings to emergent trees were investigated in five dipterocarp species in a Malaysian tropical rain forest. Canopy openness increased significantly with tree height. Photosynthetic properties, such as photosynthetic capacity at light saturation, light compensation point, maximum rate...

The present study aims to investigate the differences in leaf pigment content and the photosynthetic characteristics under natural and low light intensities between the Chinese native Physocarpus amurensis Maxim and the imported Physocarpus opulifolius "Diabolo" from North America. We aim to discuss the responses and the adaptive mechanism of these two cultivars of Physocarpus to a low light en...

Seasonal drought can severely impact leaf photosynthetic capacity. This is particularly important for Mediterranean forests, where precipitation is expected to decrease as a consequence of climate change. Impacts of increased drought on the photosynthetic capacity of the evergreen Quercus ilex were studied for two years in a mature forest submitted to long-term throughfall exclusion. Gas exchan...