The water potential (Ψ) of the sweet cherry fruit and its two components, osmotic potential (Ψ Π ) and turgor (Ψ P ) (where Ψ = Ψ Π + Ψ P ), are likely to be important factors affecting fruit cracking. First, fruit Ψ affects the rate of water
Eckhard Grimm and Moritz Knoche
Jinmin Fu, Bingru Huang, and Jack Fry
for tall fescue subjected to the 20% ETo irrigation level and lower at 20 d after treatment began for the 60% ETo irrigated level ( Table 1 ). Osmotic potential was lower in the 20% or 60% ETo treatment compared with the well-watered control on all
W.G. Yang and D.M. Glenn
The osmotic potential and development of apple and peach floral and vegetative buds and tissue were determined pre- and post-bloom. Apple and peach floral and vegetative buds were removed pre-bloom and the osmotic potential and bud development measured pre- and post-bloom. The osmotic potential of vegetative and floral buds was related to the phenology of bud development. Developing buds had a lower (more negative) osmotic potential than dormant buds. Removal of peach floral buds lowered osmotic potential and increased vegetative bud development and early leaf growth rate. Removal of peach vegetative buds, however, reduced fruit bud development, fruit growth, and embryo survival. Osmotic potential was an index of sink activity during the pre- and post-bloom stages of development.
Dougles D. Archbold
Absolute and relative fruit growth rates (AGR and RGR) of 5 cultivars were calculated from the oven-dry weights of fruits harvested periodically throughout the growing season. Both AGR and RGR were higher for larger fruit of different cultivars with similar days to maturity, and for summer- versus fall-ripening cultivars. Seasonal variability in AGR and RGR was observed, Apple fruit cortex disks were incubated in 14C-sorbitol solutions in vitro to determine if uptake rates at the cellular level varied between cultivars. Rates of sorbitol accumulation, expressed es μg sorbitol per mg dry weight cortex tissue, declined as the season progressed. Within a cuitivar, uptake rates were not relatad to fruit size, nor were differences found between cortex tissue samples from competing fruit on a spur. Sorbitol uptake rates were significantly lower for the more slowly-growing cultivar. The osmotic potential of the expressed cortex sap, sampled on several dates, was consistently lower for the more rapidly-growing cultivar. Thus, inherent differences in fruit growth rates among cultivars may be due to variation in regulation of osmotic potential.
Yehoshua Saranga, Y.-H. Kim, and Jules Janick
Effects of reduced osmotic potential on somatic embryos of celery (Apium graveolens L.) were studied in an attempt to understand and improve their tolerance to partial desiccation. Embryos responded similarly to application of high osmoticum (384 mOs/kg H2O vs. 190 mOs/kg H2O in the control), achieved either by manipulation of sucrose or polyethylene glycol concentrations (PEG). Treatments of high osmotic concentration applied during the last 2 days of the embryo production cycle increased embryo survival and conversion after partial desiccation. The most striking effect of the high osmotic concentrations was the 4-fold increase in proline, while a 2-fold increase was obtained with 1 μm ABA alone. Application of high osmotica decreased reducing sugars, increased sucrose, but did not affect starch content of embryos; of these responses, only the change in sucrose was similar to that induced by ABA. Osmotic treatments did not affect total fatty acid content in the embryos compared to the 2-fold increase induced by ABA. Chemical name used: abscisic acid (ABA).
Sanliang Gu, Lailiang Cheng, and Leslie H. Fuchigami
`Early Girl' tomato plants (Lycopersicon esculentum Mill.) were grown in a medium containing peatmoss and perlite (60%:40% by volume). The medium was drenched with 0% or 5% GLK-8924 antitranspirant. Half of the plants were flushed daily with 250 mL water (leaching), and the other half were subirrigated by capillarity. The solution osmotic potential of the medium was reduced significantly by 5% GLK 8924 treatment, then recovered gradually to the control level after 3 days with leaching or 10 days without leaching. Leaf stomatal conductance, transpiration rate, and plant growth were depressed by the antitranspirant application, and the depression was alleviated by leaching. Neither antitranspirant GLK-8924 treatment nor leaching influenced leaf abscisic acid (ABA) content. The effect of the antitranspirant on leaf gas exchange and plant growth was highly related to the reduction in the solution osmotic potential of the medium, but not to leaf ABA content. Younger leaves had higher stomatal conductance and transpiration rate but lower ABA content than older leaves in general.
D. Joseph Eakes, Robert D. Wright, and John R. Seiler
Abbreviations: EC, electrical conductivity; MSC, moisture stress conditioning; P L , leaf turgor potential; PV, pressure-volume; RWC, relative leaf water content; SWC, symplastic water content; ψ L , leaf water potential; π 100 , π 0 osmotic
Sachiko Kawamura, Kyoko Ida, Masako Osawa, and Takashi Ikeda
measured water status. We analyzed sugar contents by high-performance liquid chromatography (HPLC), and water status [water potential, osmotic potential (ψ S ) = osmotic pressure, turgor pressure] with an isopiestic thermocouple psychrometer, and measured
Nadia Jiménez-Peña, Luis A. Valdez-Aguilar, Ana M. Castillo-González, María T. Colinas-León, Andrew D. Cartmill, and Donita L. Cartmill
measured as osmotic potential (ψ S ) –0.051, –0.076, and –0.101 MPa. The response to the mixtures is represented in an equilateral triangle ( Fig. 1 ) on which each vertex corresponds to one component. On the sides of the triangle, there are the binary
Michela Centinari, Maria S. Smith, and Jason P. Londo
apex) was assessed on a five-point scale as in Fuller et al. (2003) , where 0 = no visible injury, 1 = slight, 2 = moderate, 3 = severe, and 4 = complete kill. Osmotic potential measurement. In Mar. 2015, buds were forced from stored ‘Albariño