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  • Author or Editor: Julian C. Crane x
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Abstract

We found in light and scanning electron microscopic studies of buds of the pistillate ‘Kerman’ pistachio (Pistacia vera L.) that about 12 months elapsed from the time of inflorescence differentiation until the opening of individual flowers. Growth of the rachis and its lateral branches occurred from April to June; sepal differentiation, from late May to mid June; pistil initiation, from early October to March; and carpel development, from late March to early April. Cessation of the development of the inflorescence buds during July, August, and early September appears to be unrelated to nut growth and development, as buds were inactive during that period in both bearing and nonbearing trees.

Open Access

Abstract

Markedly different curves of growth of the pistachio nut were obtained when increases in cross-diameter, fresh weight and dry weight were plotted. The dry weight data indicated that carbohydrates are not involved in abscission of inflorescence buds and resulting alternate bearing, as previously reported.

The predominant sugar in the kernel was sucrose, followed in decreasing order by glucose, fructose, and inositol (a sugar alcohol). Total sugars reached a peak of 43.3% of the dry weight early in development of the kernel, but then decreased to 7% at nut maturity. Concomitantly, crude fat increased from a low of 3.2% early in kernel development to a maximum of 40.1% at maturity.

Open Access

Abstract

Alternate bearing in the pistachio, in contrast to other tree fruit species, is caused by abscission of abundant inflorescence buds during the heavy crop year. Bud abscission was found to increase as the number of nuts per branch increased. Branch girdling between the developing nuts on 1-year-old wood and the inflorescence buds on current wood reduced bud abscission to practically the same extent as that resulting from removing the young nuts from the branches. Application of para-chlorophenoxyacetic acid delayed but did not alter the degree of bud abscission. The greater the crop load in 1970, the shorter the shoot growth in length in 1971.

Open Access

Abstract

In contrast to other fruit tree species that produce flower buds in limited quantity at the same time a heavy crop is being produced, the pistachio (Pistacia vera L.) produces abundant inflorescence buds which, for the most part, abscise during the summer. Thus, alternate bearing in the pistachio is effected by a unique mechanism. Evidence is presented which suggests that the abscission of the inflorescence buds is the result of assimilate depletion when a heavy crop is produced.

Open Access

Abstract

Olive oil application during an approximate 10-day period following the time at which all drupelets within ‘Mission’ fig fruits had turned red was effective in stimulating fruit growth and maturity. Olive oil was found to yield ethylene, particularly when exposed to solar irradiation, and it is this degradation product that undoubtedly is the stimulative agent.

Open Access

Abstract

Respiration rate of whole ‘Kerman’ pistachio (Pistacia vera L.) fruit increased progressively during seed growth and development and gradually declined after the completion of seed growth. Blank (seedless) fruit, on the other hand, respired at a constant rate which was 5 to 6 times lower than that of fruit with seeds. There was no indication of a climacteric peak in respiration of fruit with seeds. Ethylene evolution from seeded fruit was not significantly different from that of blank fruit. Constant low levels of ethylene were maintained throughout the period of shell and hull dehiscence, as well as fruit maturation, indicating that this hormone is probably not involved in those processes.

Open Access

Abstract

Five to 6 weeks elapsed between full bloom and zygote division of ‘Kerman’ pistachio (Pistacia vera L.). Various patterns of cell division in the proembryo, after transverse division in the zygote, brought about formation of a globular to heart-shaped embryo in the following 3–4 weeks. Cell enlargement in the cotyledons during the subsequent 4–5 weeks contributed mainly to final embryo size. The transition from free-nuclear to cellular endosperm was not limited to a definite stage of embryo development. The endosperm was almost digested by the time the embryo reached its ultimate size.

Open Access

Abstract

The levels of gibberellin-like substances in developing fruits and in developing inflorescence buds appear to have no relationship to abscission of the latter and consequent alternate bearing in pistachio (Pistacia vera L.).

Open Access

Abstract

Ethephon did not increase shell dehiscence in pistachio, Pistacia vera L., and caused excessive gum exudation from the trunk and framework branches and severe flower bud abscission.

Open Access

Abstract

Maleic hydrazide (MH) was readily translocated in the apricot tree, as indicated by inhibition of shoot growth and seed abortion in the fruits. However, cambial activity was undisturbed, and trunk growth proceeded normally.

Open Access