A meta-analysis of the effects of frugivory (endozoochory) on seed germination: role of seed size and kind of dormancy

Heretofore, no study has determined how germination of ingested seeds is affected by the kind (class) of dormancy nor by seed dormancy x seed size interaction. Thus, we aimed to determine the effects of seed size, kind of dormancy and their interaction on germination of defecated seeds using a meta-analysis. We collected data for 366 plant species in 97 plant families from 76 publications. In general, gut passage significantly increased germination percentage of defecated seeds by 5% compared with that of control seeds. Germination percentages of non-dormant, physiologically dormant, and morphologically/morphophysiologically dormant seeds (all water-permeable) significantly decreased after gut passage by 40, 18, and 14%, respectively, compared with control seeds (non-gut-passed). Changes in germination percentage of seeds with physical dormancy (water-impermeable) were positive, and gut passage increased germination by 69% compared with control seeds. Germination of small seeds decreased 8% after gut passage, whereas germination of both medium and large seeds increased by 18%. However, changes in germination percentage differed between categories of seed size in each class of dormancy. In physically dormant seeds, germination of all seed sizes improved after gut passage, and the magnitude of increase was higher for large than for medium and small seeds. Thus, gut passage increased germination of medium-size water-permeable seeds (physiologically dormant and morphologically/morphophysiologically dormant) more than it did for large and small seeds. However, gut-passage decreased or did not change the germination percentage of non-dormant seeds. Seed size and kind of dormancy should be included in studies on the effect of gut passage on germination.     

Assessment of thermal dehydration using the human eye: What is the potential?

Human hydration assessment is a key component for the prevention and proper treatment of heat-related fluid and electrolyte imbalances within military, sports and clinical medicine communities. Despite the availability of many different methods for assessing hydration status, the need for a valid method or technology that is simple, rapid, non-invasive, universal (detects both hypertonic and isotonic hypovolaemia) and is applicable for static (single point in time) and dynamic (change across time) hydration assessment is widely acknowledged. The eye is one candidate body region that might afford such a measure given the intricate balance between ocular dynamics (tear and aqueous humor formation) and blood (plasma osmolality and volume), which is considered the criterion measure for hydration assessment. The aim of this review is to introduce and discuss the potential for using ocular measurements for non-invasive hydration assessment, including tear fluid osmolarity (Tosm), non-invasive tear break-up time (NITBUT) and intraocular pressure (IOP). There is a relevant physiological basis for testing the merit of ocular measures for human hydration assessment and recent data indicate that Tosm and IOP may have utility. Further investigations are warranted to determine the degree to which ocular measures can act as accurate and reliable non-invasive hydration status markers.