Discriminant analysis is an important method in multivariable statistic analysis to show what type an individual should belong to. Based on actual field photosynthetic value set obtained from our research platform, North East China Transect (NECT), a new approach, developed from the concept and principle of discriminant analysts, was proposed to distinguish C3 and C4 plants. Indices related to plant photosynthetic capacity measured by an LCA4 photosynthesis system were selected to build the discriminant model which is based on four related parameters: net photosynthetic rate, transpiration rate, stomatal conductance, and difference in temperature between leaf surface and atmosphere. Compared with other approaches, the present one is fast, straightforward, and efficient. and H. P. Tang, X. S. Zhang.
Ability of detergents digitonin (Dg), Triton X-IOO (TX), sodium dodecylsulphate (SDS), cetylpyridinium chloride (CPC), and Zwittergents 3-12 (Z-12), 3-14 (Z-14), and 3-16 (Z-16) to fragment unstacked thylakoid membranes was tested in French beán (Phaseolus vulgaris L.) leaves differing in age. The power of selected detergents to initiate fragmentation did not differ with different Chemical structure and molecular size of detergents, but it was controlled more probably by their molecular charge and shape. Unfavourable was the presence of positive charge and the absence of alkyl chain in detergent molecule. Membrane fragments obtained after the action of individual detergents on agranal thylakoids were separated on a Percoll gradient. Separated fractions were characterized by their chlorophyll (Chl) content, Chl a/b and Chl/protein ratios, position of absorption maximum (A^gx) i” spectral region and ratios of intensities of fluorescence emission bands. Since separation of no Chl-protein was achieved, no priority of detergent binding to any membrane component occurred under the conditions ušed. Fractions of similar density, products of the action of low concentrations of different detergents on the chloroplasts from leaves of the same age, differed in their characteristics. Low concentrations of detergents fragmented agranal membranes in a pattem which changed during leaf ontogeny. Only Z-16 had an increased capacity to extract proteins from membrane; this was probably promoted by the presence of 16-C alkyl chain.