ULTRASTRUCTURAL CHANGES IN CHLOROPLASTS OF AUTUMN LEAVES

1971 ◽  
Vol 13 (3) ◽  
pp. 550-559 ◽  
Author(s):  
Mark E. Stearns ◽  
E. B. Wagenaar
Keyword(s):  
Populus Tremuloides ◽  
Ultrastructural Changes ◽  
Starch Granules ◽  
Membrane Structures ◽  
Mesophyll Cells ◽  
Stroma Lamellae ◽  
Typical Summer ◽  
Palisade Cells ◽  
Acer Ginnala ◽  
Rhus Typhina

The phenomenon of aging of leaves in autumn was studied in three deciduous trees, viz. Acer ginnala Maxim., Populus tremuloides Michx. and Rhus typhina L. The leaves were collected at three stages of development: at maximum summer development, at early senescence, and at a full senescence. Electron microscope studies of fully matured leaves generally showed lens-shaped chloroplasts fairly uniform in shape and size with extensive granalamellae, large starch granules and a few small lipid globules. Green, partly senescent leaves had somewhat smaller chloroplasts with large lipid globules within the reduced stroma-lamellae; virtually no starch granules were present. Fully senescent, brightly coloured, autumn leaves showed a definite decrease in size and number of chloroplasts. These plastids had lost their typical summer structure, were small and cylindrical, and contained densely packed globules that replaced the membrane structures. The presence of the carotenoids in these globules probably contributed to the autumn pigmentation of the leaves. Not all leaf cells followed the above described pattern of senescence at the same rate. The chloroplasts of palisade cells degraded earlier than those in the mesophyll cells.

scholarly journals Ultrastructural and Surface Features of Apple Leaves following White Apple Leafhopper Feeding

HortScience ◽  
1996 ◽  
Vol 31 (2) ◽  
pp. 249-251
Author(s):  
Robert M. Welker ◽  
Richard P. Marini ◽  
Douglas G. Pfeiffer
Keyword(s):  
Cell Injury ◽  
Stomatal Density ◽  
Starch Granules ◽  
Feeding Damage ◽  
Abaxial Epidermis ◽  
Mesophyll Cells ◽  
Spongy Mesophyll ◽  
Transmission Electron ◽  
Feeding Area ◽  
Palisade Cells

White apple leafhopper (WALH; Typhlocyba pomaria McAtee) feeding damage on apple (Malus domestica Borkh.) leaves was examined with scanning and transmission electron microscopy. WALH created feeding holes in the (lower) abaxial epidermis, with no visible exterior evidence of cell injury to the adaxial (upper) epidermis. Feeding holes were located in areas of the leaf with high stomatal density and were near stomata. Groups of cells in the palisade layers were empty or contained coagulated cell contents. Adjacent, apparently noninjured, palisade cells contained an abundance of starch granules, possibly indicating that photoassimilate export was impaired. Spongy mesophyll cells abaxial to the feeding area were left intact as were the epidermal cells adaxial to the feeding area. External views of either epidermis and internal leaf views of injured cells indicated no cell wall collapse.

Effect of chlorsulfuron on assimilate transport: ultrastructural implications

Weed Science ◽  
1997 ◽  
Vol 45 (4) ◽  
pp. 470-473 ◽  
Author(s):  
Songmun Kim ◽  
Sangsop Han ◽  
William H. Vanden Born
Keyword(s):  
Cell Damage ◽  
Assimilate Transport ◽  
Ultrastructural Changes ◽  
Starch Granules ◽  
Mesophyll Cells ◽  
Companion Cells

To determine if cell damage could account for chlorsulfuron inhibition of assimilate transport, the ultrastructure of companion cells and surrounding mesophyll cells was examined following chlorsulfuron treatment. Six hours after treatment of canola leaves, thylakoids in companion cells were swollen and chloroplast structures in mesophyll cells were disorganized. Three days after treatment, the treated leaves contained more starch granules in companion cells than corresponding control leaves, presumably as a result of reduced assimilate export. We conclude that the inhibition of assimilate export in chlorsulfuron-treated canola leaves is associated, at least in part, with the ultrastructural changes described, particularly those in companion cells.

Ultrastructure and Senescence in an Achloroplastic Mutant of Hordeum vulgare L. cv. Dyan

1992 ◽  
Vol 50 (1) ◽  
pp. 844-845
Author(s):  
R.H.M. Cross ◽  
C.E.J. Botha ◽  
A.K. Cowan ◽  
B.J. Hartley
Keyword(s):  
Cell Wall ◽  
Hordeum Vulgare ◽  
Leaf Tissue ◽  
Ultrastructural Changes ◽  
Hordeum Vulgare L ◽  
Mesophyll Cells ◽  
Lethal Mutant ◽  
Cytoplasmic Matrix ◽  
Close Proximity ◽  
Pinocytotic Vesicles

Senescence is an ordered degenerative process leading to death of individual cells, organs and organisms. The detection of a conditional lethal mutant (achloroplastic) of Hordeum vulgare has enabled us to investigate ultrastructural changes occurring in leaf tissue during foliar senescence.Examination of the tonoplast structure in six and 14 day-old mutant tissue revealed a progressive degeneration and disappearance of the membrane, apparently starting by day six in the vicinity of the mitochondria associated with the degenerating proplastid (Fig. 1.) where neither of the plastid membrane leaflets is evident (arrows, Fig. 1.). At this stage there was evidence that the mitochondrial membranes were undergoing retrogressive changes, coupled with disorganization of cristae (Fig. 2.). Proplastids (P) lack definitive prolamellar bodies. The cytoplasmic matrix is largely agranular, with few endoplasmic reticulum (ER) cisternae or polyribosomal aggregates. Interestingly, large numbers of actively-budding dictysomes, associated with pinocytotic vesicles, were observed in close proximity to the plasmalemma of mesophyll cells (Fig. 3.). By day 14 however, mesophyll cells showed almost complete breakdown of subcellular organelle structure (Fig. 4.), and further evidence for the breakdown of the tonoplast. The final stage of senescence is characterized by the solubilization of the cell wall due to expression and activity of polygalacturonase and/or cellulose. The presence of dictyosomes with associated pinocytotic vesicles formed from the mature face, in close proximity to both the plasmalemma and the cell wall, would appear to support the model proposed by Christopherson for the secretion of cellulase. This pathway of synthesis is typical for secretory glycoproteins.

Ultrastructural Changes of the Tissue Thromboplastin after Intravenous Injection in Rabbits

1978 ◽  
Vol 39 (01) ◽  
pp. 201-209 ◽  
Author(s):  
Hiroshi Hasegawa ◽  
Hiroshi Nagata ◽  
Makoto Murao
Keyword(s):  
Intravenous Injection ◽  
Vascular Endothelium ◽  
Model Experiment ◽  
Venous Return ◽  
Ultrastructural Changes ◽  
Membrane Structures ◽  
Tissue Thromboplastin ◽  
Short Time ◽  
Sheet Membrane

SummaryAttempts were made to demonstrate ultrastructural changes of the tissue thromboplastin after intravenous injection, as a model experiment on the pulmonary microthrombi formation induced by the tissue thromboplastin circulating from venous return.Concentrically arranged membrane structures of the injected thromboplastin disappeared in extremely short time after the injection of the thromboplastin in rabbits. The long sheet membrane of the injected thromboplastin was frequently seen as adhered to the vascular endothelium or to the surface of blood corpuscles. Furthermore, fibrin fibres were formed in contact with the long sheet membrane of the thromboplastin. Membrane structures were not found anywhere in the control rabbits.

scholarly journals FINE STRUCTURAL CHANGES IN PROPLASTIDS DURING PHOTODESTRUCTION OF PIGMENTS

1964 ◽  
Vol 22 (2) ◽  
pp. 443-451 ◽  
Author(s):  
Shimon Klein ◽  
Lawrence Bogorad
Keyword(s):  
Fine Structure ◽  
Levulinic Acid ◽  
Structural Changes ◽  
Prolamellar Body ◽  
Membrane Structures ◽  
Lamellar Structures ◽  
Amino Levulinic Acid ◽  
Stroma Lamellae ◽  
Green Pigments ◽  
Bean Leaves

Etiolated bean leaves supplied δ-amino-levulinic acid in the dark synthesize large amounts of protochlorophyllide which is not converted to chlorophyllide upon illumination of the leaves. The fine structure of the proplastids is not affected by the treatment. When leaves containing "inactive" protochlorophyllide are exposed to light of 700 ft-c for 3 hours, they lose practically all their green pigments. During this period large stacks of closed membrane structures are built up in the region of the prolamellar body. These lamellar structures remain even when no or only traces of pigment are left in the leaves. In untreated control leaves the pigment content remained constant during similar illumination and the structural changes in the plastids consisted of a rearrangement of the vesicles from the prolamellar bodies into strands dispersed through the stroma; lamellae and grana formation occurred later.

THE INHERITANCE AND HISTOLOGY OF A CHLOROPHYLL-DEFICIENT CHARACTER IN MEDICAGO SATIVA L.

1961 ◽  
Vol 39 (4) ◽  
pp. 847-853 ◽  
Author(s):  
W. R. Childers ◽  
H. A. McLennan
Keyword(s):  
Recessive Gene ◽  
Single Recessive Gene ◽  
Mesophyll Cells ◽  
Genetic Studies ◽  
Continuous Layer ◽  
Mesophyll Tissue ◽  
Plant Stage ◽  
Chlorophyll Production ◽  
Medicago Sativa L ◽  
Palisade Cells

Further support for tetrasomic inheritance in alfalfa was shown from genetic studies of a chlorophyll-deficient seedling character. The character was determined by a single recessive gene for which the symbol Viridis-1 or v1 is proposed. At the mature-plant stage, low and intermediate classes for chlorophyll production were observed. Histological examination and chlorophyll analyses confirmed this classification. The low-chlorophyll-producing class was characterized by a lack of plastids in the leaf blades although some plastids occurred in mesophyll tissue around the midrib. The intermediate chlorophyll-deficient class was characterized by yellowish-green leaf blades, associated with colorless palisade cells that overlay a single continuous layer of mesophyll cells in which the plastids were well developed.

Histopathological and ultrastructural comparison of Stemphylium sarcinaeforme and S. botryosum on red clover foliage

1978 ◽  
Vol 56 (17) ◽  
pp. 2097-2108 ◽  
Author(s):  
Verna J. Higgins ◽  
G. L. Lazarovits
Keyword(s):  
Cell Walls ◽  
Light And Electron Microscopy ◽  
Red Clover ◽  
Epidermal Cells ◽  
Blue Staining ◽  
Mesophyll Cells ◽  
Toluidine Blue Staining ◽  
Different Types ◽  
Wall Appositions ◽  
Palisade Cells

As part of a continuing study of non-host resistance, red clover leaves inoculated with the clover pathogen Stemphylium sarcinaeforme, or the closely related alfalfa pathogen S. botryosum, were examined by light and electron microscopy to compare the events occurring in the initial stages of infection. Stemphylium botryosum penetrated leaves primarily via the stomata with resultant death of the guard cells and with varying effects on adjacent epidermal cells. Appressoria were frequently formed, and although they rarely resulted in successful penetrations, the contacted epidermal cells were often markedly affected as judged by toluidine blue staining. Growth of hyphae was intercellular but very limited in its extent. At some infection sites, one to several mesophyll cells underwent extensive plasmolysis and cytoplasmic disruption. Less severely affected mesophyll cells contained large lipid bodies, abundant rough endoplasmic reticulum, and Golgi vesicles and had wall appositions at points of contact with necrotic cells or with hyphae. Stemphylium sarcinaeforme generally penetrated between or directly through the epidermal cells, causing death of the contacted cells. Hyphae grew intercellularly or intracellularly in the palisade tissue and hyphal elongation was considerably more rapid than that of S. botryosum. Palisade cells adjacent to, or containing, the hyphae underwent several different types of cytoplasmic deterioration. Mesophyll cells surrounding these areas showed the same features as comparable cells in tissue infected by S. botryosum. In tissue infected by either fungus, the exterior of host cell walls was coated with a layer of extracellular material.

Ultrastructural observations on guard cells of Vicia faba and Allium porrum

1972 ◽  
Vol 50 (6) ◽  
pp. 1405-1413 ◽  
Author(s):  
W. G. Allaway ◽  
George Setterfield
Keyword(s):  
Vicia Faba ◽  
Small Groups ◽  
Guard Cell ◽  
Cell Walls ◽  
Guard Cells ◽  
Cell Physiology ◽  
Allium Porrum ◽  
Starch Granules ◽  
Mesophyll Cells ◽  
Guard Cell Chloroplasts

Stomata of Vicia faba and Allium porrum were examined in thin section with the electron microscope. Guard cells contained numerous mitochondria, few plastids, and relatively small vacuoles traversed by many strands of cytoplasm. Spherosomes were often observed but were variable in occurrence. Endoplasmic reticulum and dictyosomes were present, although not well developed. Scattered microtubules were present at the periphery of the cells. Microbodies were very rarely observed in guard cells and no plasmodesmata were ever seen in the guard cell walls. Plastids were small and irregular in outline in guard cells of both species. Guard cell plastids of V. faba contained abundant large starch granules. In both species thylakoids were few and grana were small in comparison with mesophyll plastids. The inner of the two bounding membranes of guard cell chloroplasts was extensively invaginated, forming a peripheral reticulum. This was not observed in mesophyll plastids of these species. Small groups of microtubule-like structures were often observed in V. faba guard cell plastids; microtubule-like structures were less frequent in A. porrum plastids, and were not in groups. The structures described are compared with those of other epidermal cells and mesophyll cells, and are discussed in relation to guard cell physiology.

Degeneration of leaf cells resulting from starvation after excision. I. Electron microscopic observations

1970 ◽  
Vol 48 (11) ◽  
pp. 1913-1922 ◽  
Author(s):  
H. W. J. Ragetli ◽  
M. Weintraub ◽  
Esther Lo
Keyword(s):  
Nuclear Membrane ◽  
Nuclear Material ◽  
Ultrastructural Changes ◽  
Cell Aging ◽  
Starvation Stress ◽  
Electron Microscopic ◽  
Nicotiana Glutinosa ◽  
Mesophyll Cells ◽  
Unequal Distribution ◽  
3 Dimensional

Mesophyll cells of Nicotiana glutinosa exposed to starvation in the light after leaf excision showed the following major changes: vacuolation of the cytoplast; rearrangement of chloroplast and nuclear material; accumulation of cytoplasmic crystals and of starch; evagination and increased perforation of the nuclear membrane; and lysis of the tonoplast. Rearrangement of chloroplast material resulted in extended, 3-dimensional arrays (pseudocrystalline bodies), composed of electron-dense globules 85–100 Å in diameter. The ultrastructural degeneration of cells within a leaf was unsynchronized, and the sequence of degenerative intracellular events was not fixed. These observations are compatible with an unequal distribution of "essential" metabolites among those cells. Cells suffering from starvation stress showed ultrastructural changes not observed in cells of aging attached leaves and vice versa. Thus, starvation stress does not merely accelerate the process of cell-aging, as it operates in attached leaves.

scholarly journals Paclobutrazol-induced Leaf, Stem, and Root Anatomical Modifications in Potato

HortScience ◽  
2005 ◽  
Vol 40 (5) ◽  
pp. 1343-1346 ◽  
Author(s):  
Tekalign Tsegaw ◽  
S. Hammes ◽  
J. Robbertse
Keyword(s):  
Foliar Spray ◽  
Potato Cultivar ◽  
Root Diameter ◽  
Vascular Bundles ◽  
Starch Granules ◽  
Cortical Cells ◽  
Mesophyll Cells ◽  
Spongy Mesophyll ◽  
Dark Green ◽  
Epicuticular Wax Layer

Potato (Solanum tuberosum L.) treatment with paclobutrazol resulted in short and compact plants having dark green and thicker leaves, and wider stem and root diameters. Investigating the underlying anatomical modifications in response to the treatment was the objective of the study. Plants of potato cultivar BP 1 were treated with 0, 45.0, 67.5, and 90.0 mg paclobutrazol per plant as a foliar spray. A month after treatment leaf, stem and root materials were taken from the control and plants treated with 67.5 mg paclobutrazol, and histological observations were made using light microscope. Leaves of treated plants showed an increased chlorophyll a and b contents, thicker epicuticular wax layer, elongated and thicker epidermal, palisade and spongy mesophyll cells. paclobutrazol increased stem diameter by about 58% due to induction of thicker cortex, larger vascular bundles, and wider pith diameter associated with larger pith cells. Widening the cortex and the induction of more secondary xylem vessels in response to paclobutrazol treatment increased the root diameter by about 52%. Paclobutrazol treatment remarkably increased the accumulation of starch granules in the stem pith cells and cortical cells of the stem and root. This study is similar to the other relevant studies in reporting an increased leaf thickness, and stem and root diameters; however, most of the underlying anatomical modifications described above have not been reported previously.

Sign in / Sign up

Export Citation Format

Share Document