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Embryo dormancy of Taxus baccata var. fastigiata is eliminated when cultured continuously in nutritive liquid medium. An equivalent percentage of germination is obtained when the embryos are transferred to agar medium after 8 days of liquid culture. There is no morphological development of the embryo during the period in the liquid medium. But we have ascertained that water-soluble germination inhibitors present in the embryo are leached out into the medium, permitting germination. Germination is totally absent when the embryos are cultured continuously in distilled water, alone or with minerals; incidental in sucrose solution; and maximal when the medium contains sucrose and Ca2+ or K+ ions. The extent of germination on agar medium depends upon the composition of the liquid medium in which the embryos are cultured for the initial 8 days. But this preliminary culture in the liquid medium does not always remove the endogenous inhibitors, irrespective of its composition. This can be achieved only in the presence of sucrose; and this process can be made more effective by the addition of Ca2+ ions. [ABSTRACT FROM AUTHOR]

Germination Heterogeneity of Rumex crispus L. seeds: Occurrence and Attempt at Interpretation. Rumex crispus L. seeds, harvested without taking into account localization of mother plants or seed position on single plants differ in their response to unfavourable conditions inductive of dormancy as a function of their weight. During induction, application of potassium or GA3 prevents or reduces the entry into dormancy, suggesting that the observed heterogeneity is due to nutritional variations of the seeds in relation to their position on the mother plant. [ABSTRACT FROM AUTHOR]

Indoleacetic acid, tryptophan and indole promote growth of pith tissues of tumorous Nicotiana glauca x N. langsdorffii amphidiploïd hybrid, but only indoleacetic acid gives the potentiality of continuous development to the tumorous tissues after some days of contact on a medium without growth substances. In combination with 6-benzylaminopurine, tryptophan and especially indole are promoting substances like auxin for the non-tumorous pith tissues of tobacco, and allow a considerable organogenesis. [ABSTRACT FROM AUTHOR]

Starch and soluble sugars in leaves of Aster tripoIium L. and Cochlearia anglica L. Effect of NaCl. - The limbs or foliar disk of Aster tripolium L. and Cochlearia anglica L. synthetize starch when exposed to light at 25°C and in the presence if glucose or saccharose together with 0.25 to 0.61 % of NaCl. [ABSTRACT FROM AUTHOR]

The aim of this work was to determine the effect of DMSO on the uptake and translocation of potassium and phosphorus applied on corn and bean leaves. Radioactive isotopes 42K and 32P were used in most of the experiments. The results obtained reveal that DMSO (0.5% and above) increases the penetration of potassium applied as nitrate or chloride, but seems to have no effect on the penetration of 32 when applied as different phosphates. [ABSTRACT FROM AUTHOR]