Compensatory Growth in Coleus Shoots

Jacobs, William P.; Bullwinkel, Bob

doi:10.1002/j.1537-2197.1953.tb06497.x

Cited by 39 publications

(16 citation statements)

References 18 publications

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“…In C. blumei, the application of IAA to the petiolar stump of young leaves, in the presence of the apical leaves, replaced a large part of their basipetal effect on stem elongation (17). In the acropetal direction auxin had a general retardation effect (3).…”

Section: Discussionmentioning

confidence: 99%

Role of Auxin and Gibberellin in Differentiation of Primary Phloem Fibers

Aloni

1979

Plant Physiol.

107

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The hypothesis that auxin and gibberellic acid (GA3) control the differentiation of primary phloem fibers is confirmed for the stem of Coleus blumei Benth. Indoleacetic acid (IAA) alone sufficed to cause the differentiation of a few primary phloem fibers. In long term experiments auxin induced a considerable number of fibers in mature internodes. GA3 by itself did not exert any effect on fiber differentiation. Combinations of IAA with GA3 completely replaced the role of the leaves in primary phloem fiber differentiation qualitatively and quantitatively. Although the combined effect of the two growth hormones diminished considerably with increasing distance from the source of induction, auxin with GA3 or IAA alone induced fibers in a few internodes below the application site. When various combinations of both hormones were applied, high concentrations of IAA stimulated rapid differentiation of fibers with thick secondary walls, while high levels of GA3 resulted in long fibers with thin walls. The size of the primary phloem fibers correlated with the dimensions of the differentiating internode, thereby providing evidence that both growth regulators figure in the control of stem extension. High IAA/low GA3 concentrations have an inhibitory effect on internode elongation, whereas low IAA/high GA3 concentrations promote maximal stem elongation.In Coleus, the primary phloem fiber initials differentiate in the vascular bundles in the periphery of the primary sieve elements. The single nucleus of the fiber initial divides several times and cytokinesis occurs by the formation of septa (24,25). Primary phloem fiber differentiation is dependent on stimuli originating in the leaves (2, 5, 31). The stimuli for fiber differentiation flow in a strictly polar fashion from the leaves to the root (2). Leaves induce fiber differentiation in several internodes below them. Young Coleus leaves yield shorter fibers than those which differentiate under mature leaves, indicating that more than one stimulus is involved in the induction process (5).Some of the polar phenomena occurring during plant development and regeneration are attributable to the polar movement of auxins. Recently, plant hormones other than auxins have been demonstrated to move in a polar fashion through the plant tissues (18,20,21,26). Gibberellic acid which has been shown to move with basipetal polarity through sections cut from young petioles of the Princeton clone of Coleus blumei (18,20) is known to affect primary phloem fiber differentiation (9,34,36,37).In an attempt to understand the mechanism that determines and controls the polar differentiation of primary phloem fibers with sieve and vessel elements in the vascular bundles, a working hypothesis was set up as follows. Knowing that the polar movement of IAA through an organized tissue induces the differentia-' Supported in part by the Lady Davis Fellowship Trust. tion of a vascular bundle which consists of sieve tubes or sieve tubes and vessels (15,23,38), it was hypothesized that when an additional p...

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Section: Discussionmentioning

confidence: 99%

Role of Auxin and Gibberellin in Differentiation of Primary Phloem Fibers

Aloni

1979

Plant Physiol.

107

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“…This effect was not seen in randomly selected seeds (21.7 ± 1.97) mg (data not given, cf. Jacobs and Bullwinkel, 1953;Jacobs and Suthers, 1974). Thus the life stages, unlike biomass per se, appear to be less susceptible to energy partitioning inherent to environment-induced variation.…”

Section: Energy Partitioningmentioning

confidence: 99%

Respiration hastens maturation and lowers yield in rice

Sitaramam

Bhate

Kamalraj

et al. 2008

Physiol Mol Biol Plants

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Role of respiration in plant growth remains an enigma. Growth of meristematic cells, which are not photosynthetic, is entirely driven by endogenous respiration. Does respiration determine growth and size or does it merely burn off the carbon depleting the biomass? We show here that respiration of the germinating rice seed, which is contributed largely by the meristematic cells of the embryo, quantitatively correlates with the dynamics of much of plant growth, starting with the time for germination to the time for flowering and yield. Seed respiration appears to define the quantitative phenotype that contributes to yield via growth dynamics that could be discerned even in commercial varieties, which are biased towards higher yield, despite considerable susceptibility of the dynamics to environmental perturbations. Intrinsic variation, irreducible despite stringent growth conditions, required independent validation of relevant physiological variables both by critical sampling design and by constructing dendrograms for the interrelationships between variables that yield high consensus. More importantly, seed respiration, by mediating the generation clock time via variable time for maturation as seen in rice, directly offers the plausible basis for the phenotypic variation, a major ecological stratagem in a variable environment with uncertain water availability. Faster respiring rice plants appear to complete growth dynamics sooner, mature faster, resulting in a smaller plant with lower yield. Counter to the common allometric views, respiration appears to determine size in the rice plant, and offers a valid physiological means, within the limits of intrinsic variation, to help parental selection in breeding.

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“…For grain yield, there is only a basipetal compensatory relationship between functional earshoots and nonfunctional earshoots; however, this compensatory relationship does not come into play unless one or more of the functional earshoots fail to develop as has also been discussed in other plants by Jacobs and Bullwinkel (1953). In my experiment, there was no removal of the top ear, but I attempted to compensate for the in hibitory effect of apical dominance by the top ear by application of growth regulators.…”

Section: Effect Of Hormones On Third Ear Developmentmentioning

confidence: 84%

The effect of hormones and chemical growth regulators on ear development and grain yield of nonprolific corn (Zea mays L.)

Khosravi

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Compensatory Growth in Coleus Shoots

Cited by 39 publications

References 18 publications

Role of Auxin and Gibberellin in Differentiation of Primary Phloem Fibers

Role of Auxin and Gibberellin in Differentiation of Primary Phloem Fibers

Respiration hastens maturation and lowers yield in rice

The effect of hormones and chemical growth regulators on ear development and grain yield of nonprolific corn (Zea mays L.)

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