Ultrastructural Modifications in Cotyledonous Leaves of<i>Ricinus Communis</i>L. During Aging

Fabbri, Fernando; Palandri, Mariarosa

doi:10.1080/00087114.1970.10796403

Cited by 7 publications

(5 citation statements)

References 27 publications

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“…The cytological changes described here, in the mesophyll tissue that is remote from the major vein, resemble closely those associated with senescence (Barton 1966;Fabri and Palandri 1970;Ragetli et al 1970) and are compatible with either the plugging (Vieira da Silva et al 1974) or the toxin (Goodman 1972; Strobe1 and Hess 1968) theory of wilt induction. The cytological changes described here, in the mesophyll tissue that is remote from the major vein, resemble closely those associated with senescence (Barton 1966;Fabri and Palandri 1970;Ragetli et al 1970) and are compatible with either the plugging (Vieira da Silva et al 1974) or the toxin (Goodman 1972; Strobe1 and Hess 1968) theory of wilt induction.…”

Section: Discussionsupporting

confidence: 64%

Ultrastructure of wilt syndrome caused by Verticillium dahliae. II. In sunflower leaves

Robb¹,

Busch²,

Brisson³

et al. 1975

Can. J. Bot.

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Ultrastructural changes occurred in sunflower leaves that were infected by Verticillium dahliae Kleb. during the appearance of foliar symptoms. Early in symptom development major degenerative changes took place in the leaf mesophyll tissue particularly in the vicinity of the xylem of the major veins. During these early stages vessel wall breakdown occurred in the vicinity of the fungus, but this degradation was not accompanied by swelling. Occlusion of the vessel elements by fungus, fibrillar material, or electron-dense plugs was not significant until late in disease development. Comparison of these observations with those that were made in a previous parallel study of Verticillium-infected chrysanthemum suggested that the ultrastructural changes induced by the fungus in the two hosts are similar but that the timing is different. In chrysanthemum, degenerative changes in the mesophyll are not extensive until after chlorosis, but vessel blockage is advanced before wilting is noticeable. The significance of this difference in the development of foliar symptoms is discussed in relation to the plugging and toxin theories of wilt induction in fungus-caused vascular diseases.

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Section: Discussionsupporting

confidence: 64%

Ultrastructure of wilt syndrome caused by Verticillium dahliae. II. In sunflower leaves

Robb¹,

Busch²,

Brisson³

et al. 1975

Can. J. Bot.

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“…The unusual plastids found beneath the pustules in 13-day-old rust-infected flax have some close analogies with plastids found in normal senescing tissues (7,46). In addition, the thylakoid membrane configurations show some similarities to those found in the plastids of virescent barley mutants (34), chromoplasts in daffodils (30), and chromoplasts in Valencia oranges (53).…”

Section: Discussionmentioning

confidence: 83%

“…It may be that each represents a genetically distinct organelle which responds differently to the same conditions. Alternatively, the types enumerated may be related developmentally as has been proposed for plastids in ripening fruits (16,49), and in senescing cotyledons (7). No evidence was obtained in favor of such a single developmental sequence in rust-infected tissues though it cannot be ruled out since such a process inay occur in an irregular fashion.…”

Section: Discussionmentioning

confidence: 88%

“…tissue cultures of Acer pseudopIatanus (6); in abscission zones (22,23); in TMV-infected tobacco (19,24,40); in crown gall tissue (28); and in detached senescing leaves (36). The occurrence of the crystalline lattice in microbodies is not a common feature of senescing tissues (7,36). Rather the frequency of occurrence of crystals tends to diminish with age (7).…”

Section: Discussionmentioning

confidence: 98%

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Ultrastructural changes in rust-infected tissues of flax and sunflower

Coffey¹,

Palevitz²,

Allen³

1972

Can. J. Bot.

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Similar changes occurred in the ultrastructure of host cell organelles in the rust-infected tissues of both flax and sunflower. Up to the onset of sporulation at 8 days after inoculation the only major alteration in cell structure was a marked tendency for the cell organelles to be aggregated around the intracellular fungal haustorium and an accumulation of starch in the plastids. During sporulation, however, some striking changes occurred in the structure of plastids, mitochondria, and microbodies. Eleven days after inoculation, in a zone of host tissue adjacent to the rust pustule, the plastids no longer contained starch and varied in structure even within a single cell. Some were similar to normal chloroplasts, others had larger grana, and some bore a close resemblance to chromoplasts. In sunflower, but not in flax, mitochondria contained atypical plate-like cristae in addition to the usual vesiculate type. The micro-bodies of both plant species all contained crystalline cores in contrast to earlier stages in the disease where crystals were only occasionally detected. The plastids were also altered considerably in another zone of tissue situated beneath the rust pustule. In some plastids the thylakoids extended along their long axis, forming several large grana, and in others the large grana were interconnected by lamellae arranged in a vesicular or tubular configuration. Frequently the starch grains in these plastids were broken down into small rosettes of darkly staining particles with an appearance similar to that of animal glycogen.

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“…In Tillandsia, parallel to the aging process, as suggested by some ultrastructural features observed also by FABBRI and PALANDRI (1970) in Ricinus communis L., there is the occurrence of material in the thinnest nectariferous slits and inside the cavities formed by detachment of cell walls. This indicates the beginning of a different occlusion mechanism in the nectary which involves the deposition of a substance besides the joining of cell walls.…”

Section: Discussionmentioning

confidence: 98%

Anatomic and Ultrastructural Study of the Septal Nectary in SomeTillandsia(Bromeliaceae) Species

Fiordi

Palandri

1982

Caryologia

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There is, however, a particular aspect in Tillandsia worth underlining, that is the mechanism by which the occlusion of the nectariferous slits is attained once the epithelium has become inactive. This mechanism does not only involve the approaching of the epithelium tangential cell walls, which at this stage are considerably thick, but it is due mainly to the production of a cementing substance made of acid polysaccharides.

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Ultrastructural Modifications in Cotyledonous Leaves ofRicinus CommunisL. During Aging

Cited by 7 publications

References 27 publications

Ultrastructure of wilt syndrome caused by Verticillium dahliae. II. In sunflower leaves

Ultrastructure of wilt syndrome caused by Verticillium dahliae. II. In sunflower leaves

Ultrastructural changes in rust-infected tissues of flax and sunflower

Anatomic and Ultrastructural Study of the Septal Nectary in SomeTillandsia(Bromeliaceae) Species

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