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- Author or Editor: Gerald A. Berkowitz' x
The objective of this research was to develop an effective antitranspirant formulation for reducing transplant shock (transitory water stress) in bell pepper (Capsicm annuum L.) seedlings. A formulation with a paraffin wax emulsion (Folicote at 5%) and a spreader/sticker type surfactant (Biofilm at 0.5%) was effective as an antitranspirant. This formulation was less phytotoxic than other formulations tested. Application of the formulation led to increased leaf water potential (Ψ w) i in transplanted seedlings for several days as compared with untreated transplants. When this, (relatively) nonphytotoxic formulation was used in a field study for 1 year, increased seedling Ψ w during a period of imposed water stress led to less leaf abscission and increased plant growth throughout the growing season. Chemical names used: alkylarylpolyethoxyethanol (Biofilm).
Understanding the factors influencing the performance of Kentucky bluegrass (Poa pratensis L.) cultivars under summer stress is necessary for developing criteria for identifying resistant germplasm. The objectives of this study were to evaluate two Kentucky bluegrass cultivars for leaf water (ψl) and osmotic potential (ψπ), stomatal resistance (Rs), leaf: air temperature differential (ΔT) and determine the relationship of these parameters to drought and heat tolerance. Stress-resistant (`Midnight') and susceptible (`Nugget') cultivars were evaluated in a field study during 1993 and 1994 under moisture-limiting conditions. Leaf water potential for `Nugget' was higher than for `Midnight' in 1993 and similar in 1994. `Midnight' had lower ψπ than `Nugget' during the evaluation period in 1994. `Midnight' maintained more open stomata (lower Rs) and lower ΔT than `Nugget' at the end of the dry down period when `Nugget' was showing visual signs of stress. `Midnight' and `Nugget' had similar root weight at the 0- to 45-cm depth zone in 1994. Lower basal osmotic potential (i.e., higher solute concentration) may be the physiological mechanism allowing larger stomatal aperture in `Midnight'. Greater transpirational cooling in `Midnight' relative to `Nugget' was correlated with higher turf quality for `Midnight'.
Abstract
Osmotic priming effects on stand establishment and yield were evaluated for ‘Forest Green’ parsley (Petroselinum crispum Mill.) seed sown on three dates in the field. Stand establishment occurred under progressively higher temperatures for early, middle, and late plantings. Seed priming enhanced early seeded stands 78% at one site and 76% at a second site in comparison with untreated seed. This priming effect on seedling establishment for the earliest planting led to a 67% increase in early yield (96 days from seeding) and a 28% yield increase over untreated seed at a later harvest. Stands of primed seed sown at later dates were enhanced to a lesser extent and yields were not affected by osmotic priming.
Abstract
‘Forest Green’ parsley ( Petroselinum crispum L.) seeds were leached for 3 days in aerated water at 25°C and then primed in aerated polyethylene glycol (PEG) 8000 solutions for 4.5 days at 25°. Priming improved earliness of germination at all temperatures of the tests (5°, 15°, 20°, and 25°), with the largest improvement at the coolest temperature. Uniformity of germination, as measured by the mean time between 25% and 75% germination, was not significantly affected by priming. Primed seeds germinated significantly faster than unprimed seeds when water stress was applied by low osmotic potentials (PEG solutions, -0.25, -0.5, or -0.75 MPa, were substituted for water). The latter result supports the hypothesis that priming induces the development of low cellular osmotic potentials. The priming effect was not lost during 8 months of storage, indicating a good treatment longevity.