The aim of the present review was to reconsider basic information about various functional aspects related to plant water content and provide evidence that the usefulness of measuring absolute water content in plant sciences is undervalued. First, general questions about water status in plants as well as methods for determining water content and their associated problems were discussed. After a brief overview of the structural organization of water in plant tissues, attention was paid to the water content of different parts of plants. Looking at the influence of environmental factors on plant water status, the differences caused by air humidity, mineral supply, biotic effects, salinity, and specific life forms (clonal and succulent plants) were analyzed. Finally, it was concluded that the expression of absolute water content on a dry biomass basis makes easily noticeable functional sense, but the physiological meaning and ecological significance of the drastic differences in plant water content need to be further elucidated.

Crop wild relatives represent a valuable resource for the breeding of new crop varieties suitable for sustainable productivity in conditions of climate change. The aim of the present study was to assess salt tolerance of several wild accessions of T. fragiferum from habitats with different salinity levels in controlled conditions. Decrease of plant biomass and changes in partitioning between different organs was a characteristic response of plants with increasing substrate salinity, but these responses were genotype-specific. In several accessions, salinity stimulated reproductive development. The major differences in salinity responses between various T. fragiferum genotypes were at the level of dry biomass accumulation as well as water accumulation in plant tissues, resulting in relatively more similar effect on fresh mass. Na⁺ and Cl⁻ accumulation capacity were organ-specific, with leaf petioles accumulating more, followed by leaf blades and stolons. Responses of mineral nutrition clearly were both genotype- and organ-specific, but several elements showed a relatively general pattern, such as increase in Zn concentration in all plant parts, and decrease in Ca and Mg concentration. Alterations in mineralome possibly reflect a reprogramming of the metabolism to adapt to changes in growth, morphology and ion accumulation resulting from effect of NaCl. High intraspecies morphological and physiological variability in responses of T. fragiferum accessions to salinity allow to describe them as ecotypes.

Eryngium maritimum is a coastal plant of the Apiaceae family. This species is threat­ened in several countries where it reaches the northern limits of its distribution area. Existing populations in the Baltic Region and Scandinavia are potentially affected by the low efficiency of its generative reproduction. We studied physiological aspects of its germination and dormancy breaking requirements using seeds collected from two Latvian populations. Seeds were subjected to cold and warm stratification and treatment with gibberellic acid. We monitored the development of seed embryos throughout the process of stratification at different temperatures and built a size-class structure of embryo development within a batch of seeds to visualize the developmental progress and to compare different treatments. The final germination percentage and germination rate increased after cold stratification at 5 °C in seeds germinated at 25/10 °C. Maximum germination was achieved after four months of cold stratification. Treatment with gibberellic acid had a similar dormancy breaking effect that was enhanced by previous warm stratification. The relative size of embryos increased during cold stratification, although this increase was not uniform. We conclude that in seeds of E. maritimum, embryo growth during stratification is required before germination can start and that growth is enhanced by warm stratification. Breaking the physiological component of seed dormancy requires cold stratification that can be substituted by treatment with gibberellic acid. We suggest that germination characteristics of seeds and the structure of embryo development within seeds in a particular population may reflect the state of the plant population itself and provide valuable information for research on the biology of this species.