Formation of the primary protective layer and phellogen after leaf abscission in peach

Potted peach trees (Prunus persica (L.) Batsch cv. Loring) were mechanically defoliated and the influence of temperature on formation of the primary protective layer and phellogen generation in the leaf abscission region was examined histologically. Plants maintained at 7.5, 12.5, and 17.5 °C showed first indications of primary protective layer formation at 18, 9, and 6 days, respectively. Subsequent generation of phellogen and the appearance of the first phellem cell were observed at 30, 18, and 12 days, respectively. The primary protective layer formed approximately 700 μm proximal to the separation zone and was composed of cells with lignified walls and thin suberin linings.

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Failure criteria in thin film lubrication — influence of temperature on seizing, wear and reaction layer formation

Wear ◽

10.1016/0043-1648(76)90141-1 ◽

1976 ◽

Vol 36 (1) ◽

pp. 25-32 ◽

Cited By ~ 4

Author(s):

J. Föhl ◽

H. Uetz

Keyword(s):

Thin Film ◽

Reaction Layer ◽

Failure Criteria ◽

Layer Formation ◽

Thin Film Lubrication ◽

Influence Of Temperature ◽

Influence Of Temperature On ◽

Film Lubrication

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Peach Leaves Do Take Up Foliarly Applied Urea Nitrogen

HortScience ◽

10.21273/hortsci.32.3.498b ◽

1997 ◽

Vol 32 (3) ◽

pp. 498B-498

Author(s):

Richard C. Rosecrance ◽

Scott Johnson ◽

Steven A. Weinbaum

Keyword(s):

Prunus Persica ◽

Leaf Abscission ◽

N Content ◽

Urea Nitrogen ◽

Urea Uptake ◽

Leaf Surfaces ◽

Peach Trees ◽

Foliar Urea

The ability of peach leaves to absorbed and translocated foliarly applied 15N-urea in mature peach (Prunus persica) trees was determined. Urea uptake experiments were conducted in June, October, and November 1995. Peach leaves absorbed ≈80% of the urea within 48 hr of application in all three experiments based on urea rinsed from leaf surfaces. Similarly, leaf 15N content reached a peak 48 hr after application. Translocation of 15N out of leaves, however, was more rapid in October then November. In October, 24% of the 15N remained in the leaves 2 weeks after application, while, in November, 80% stayed in the leaves and fell to the orchard floor. Thus, applying urea in mid November did not allow enough time for the N to be transported out of the leaves before leaf abscission. Timing of foliar urea application is critical to maximize N transport into perennial tissues of peach trees. 15Nurea resorption out of leaves and into perennial tree parts (roots, trunk, current year wood, etc.) is discussed.

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189 BLOOM THINNING WITH ARMOTHIN®, AN AKZO SURFACTANT

HortScience ◽

10.21273/hortsci.29.5.456b ◽

1994 ◽

Vol 29 (5) ◽

pp. 456b-456

Author(s):

Dean R. Evert

Keyword(s):

Growth Regulators ◽

Tree Growth ◽

Prunus Persica ◽

Leaf Abscission ◽

Full Bloom ◽

The Third ◽

Wide Range ◽

Peach Trees ◽

Normal Variability

Armothin® thinned `Sentinel' fruit on peach trees (Prunus persica L.) in 1993. Thinning increased as Armothin® rate in the single spray increased from 1.5X, to 3.0% to 6.0% (v:v) and as the percentage of open blossoms increased from 30% to 61%. The 1.5 % rate of Armothin® thinned significantly only on the third date, and the 6.0% rate overthinned slightly on the third date. Minor discoloration developed on the expanding leaves of a few of trees but disappeared in a few days. No leaf abscission occurred on treated trees and tree growth was normal. Variability between trees treated alike probably reflects the variability in bloom when sprayed. According to Akzo, Armothin® prevents pollination by reacting with the surface of the receptive stigma. Spraying after full bloom should selectively prevent fertilization of the last blossoms to open without destroying the fertilized fruit. This possibility will be tested in 1994. Armothin®, which is a contact thinner, seems to avoid the problems associated with thinners that act as growth regulators and with nonselective caustic thinners. Because of its low phytotoxicity and wide range of effective rates, Armothin® has great potential as a chemical thinner.

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The effect of temperature on high-resolution TEM image contrast

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100139573 ◽

1995 ◽

Vol 53 ◽

pp. 640-641

Author(s):

T. Geipel ◽

W. Mader ◽

P. Pirouz

Keyword(s):

Form Factor ◽

Inelastic Scattering ◽

Accurate Method ◽

Waller Factor ◽

Effect Of Temperature ◽

Specimen Thickness ◽

Influence Of Temperature ◽

Debye Waller Factor ◽

Influence Of Temperature On ◽

Atomic Form Factor

Temperature affects both elastic and inelastic scattering of electrons in a crystal. The Debye-Waller factor, B, describes the influence of temperature on the elastic scattering of electrons, whereas the imaginary part of the (complex) atomic form factor, fc = fr + ifi, describes the influence of temperature on the inelastic scattering of electrons (i.e. absorption). In HRTEM simulations, two possible ways to include absorption are: (i) an approximate method in which absorption is described by a phenomenological constant, μ, i.e. fi; - μfr, with the real part of the atomic form factor, fr, obtained from Hartree-Fock calculations, (ii) a more accurate method in which the absorptive components, fi of the atomic form factor are explicitly calculated. In this contribution, the inclusion of both the Debye-Waller factor and absorption on HRTEM images of a (Oll)-oriented GaAs crystal are presented (using the EMS software.Fig. 1 shows the the amplitudes and phases of the dominant 111 beams as a function of the specimen thickness, t, for the cases when μ = 0 (i.e. no absorption, solid line) and μ = 0.1 (with absorption, dashed line).

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