The role of plasma membrane aquaporins (PIPs) in water relations of Arabidopsis was studied by examining plants with reduced expression of PIP1 and PIP2 aquaporins, produced by crossing two different antisense lines. Compared with controls, the double antisense (dAS) plants had reduced amounts of PIP1 and PIP2 aquaporins, and the osmotic hydraulic conductivity of isolated root and leaf protopla...

Chloroplasts may contract under natural conditions and give up water to the rest of the cell, thus indicating changes in metabolism or constitution. Such contractions may be produced experimentally. In Nitella the chloroplasts are ellipsoid bodies which, under natural conditions, may contract to spheres with a loss of volume. This may be brought about by lead acetate, ferric chloride, and digit...

In the tomato plant water flows through primary xylem in accordance with Poiseuille's law. This relation and the analogy between Poiseuille's and Ohm's law were employed to calculate rates of flow and differences in pressure within vascular bundles when transpiration rates from individual leaves were known. The resistance of vascular bundles to flow was calculated from a modification of Poiseui...

Leaf and whole plant-level functional traits were studied in five dominant woody savannah species from Central Brazil (Cerrado) to determine whether reduction of nutrient limitations in oligotrophic Cerrado soils affects carbon allocation, water relations and hydraulic architecture. Four treatments were used: control, N additions, P additions and N plus P additions. Fertilizers were applied twi...

The use of soil and irrigation water with a high content of soluble salts is a major limiting factor for crop productivity in the semi-arid areas of the world. While important physiological insights about the mechanisms of salt tolerance in plants have been gained, the transfer of such knowledge into crop improvement has been limited. The identification and exploitation of soil microorganisms (...

The water relations of Picea abies in a healthy stand with green trees only and a declining stand with trees showing different stages of needle yellowing were investigated in northern Bavaria. The present study is based on observations of trees differing in their nutritional status but apparently green on both sites in order to identify changes in the response pattern which might be caused by a...