The effects of continuous soil hypoxia on stomatal conductance (g^ and net photosynthetic rate (P^) ů* seedlings of Taxodium disíichum, Quercus lyrata, and Q. falcata var. pagodaefolia were studied under controlled environment. Soil oxygen deficiency induced significant stomatal closure and reduction of in oak species within 1-3 d. This response pattem continued resulting in average daily values of g^ reduced 85 and 40 % within 14 d in g. falcata and Q. lyrata as compared to control plants, respectively. Ehiring the same period Pn reduced 96 and 71 % in 0. falcata and Q. lyrata as compared to control plants, respectively. In T. distichum, however, gg and Pff were reduced 18 and 33 % by day 8. Significant recoveiy of gg and was noted in T. distichum. By day 14, gg had recovered to 91 % and to 92 % of control plants. In oak species, however, remained significantly lower than in control plants without any apparent recovery. The regain of photosynthetic activity and stomatal functioning in flood-tolerant species appears to be an important flood- tolerance characteristic allowing these species to fimction under flooded soil.
We characterize the existence of the L 1 solutions of the truncated moments problem in several real variables on unbounded supports by the existence of the maximum of certain concave Lagrangian functions. A natural regularity assumption on the support is required.
The physics of the two types of resonances characterizing the dynamical structure of the asteroidal belt are presented. In the case of mean motion resonances, the frequency of Jupiter´s rotation about the Sun determines the various resonance frequencies. For secular resonances, the resonance frequencies corxespond to eigenfrequencies of the system of differential equations descríbing the motions of nodal and apsidal lines of planetary orbits. Both
types of resonances are related to gaps in the asteroidal belt. The computing theories for the formation of these gaps are reviewed. The secular resonances gained considerable interest because of their alleged role as source of Earth-crossing objects like Apollo asteroids and meteorites. Recent numerical model calculations on secular resonances are reviewed under this aspect.
We introduce the notion of order weakly sequentially continuous lattice operations of a Banach lattice, use it to generalize a result regarding the characterization of order weakly compact operators, and establish its converse. Also, we derive some interesting consequences.