Ultrastructural observations of soybean leaves affected by bacterial toxemia

1972 ◽  
Vol 50 (3) ◽  
pp. 529-531 ◽  
Author(s):  
J. Dueck ◽  
R. J. Zeyen ◽  
B. W. Kennedy

Soybean mesophyll cells from stunted and chlorotic trifoliolate leaf tissue affected by bacterial (Pseudomonas glycinea Coerper) induced toxemia, had dense cytoplasm, little vacuolation, chloroplasts with few lamellae, and little starch accumulation. Toxemia-affected cells exhibited no ultrastructural disruptions and resembled very young, healthy mesophyll cells. The main effect of the toxin appears to be a delay in mesophyll cell maturation rather than disruption at the ultrastructural level. Leaf mesophyll cells which had recovered from the bacterial toxemia appeared similar ultrastructurally to mature healthy cells, although they remained smaller.

2019 ◽  
Vol 70 (18) ◽  
pp. 4991-5002 ◽  
Author(s):  
Lukasz Kotula ◽  
Peta L Clode ◽  
Juan De La Cruz Jimenez ◽  
Timothy D Colmer

Abstract Salinity tolerance is associated with Na ‘exclusion’ from, or ‘tissue tolerance’ in, leaves. We investigated whether two contrasting chickpea genotypes, salt-tolerant Genesis836 and salt-sensitive Rupali, differ in leaf tissue tolerance to NaCl. We used X-ray microanalysis to evaluate cellular Na, Cl, and K concentrations in various cell types within leaflets and also in secretory trichomes of the two chickpea genotypes in relation to photosynthesis in control and saline conditions. TEM was used to assess the effects of salinity on the ultrastructure of chloroplasts. Genesis836 maintained net photosynthetic rates (A) for the 21 d of salinity treatment (60 mM NaCl), whereas A in Rupali substantially decreased after 11 d. Leaflet tissue [Na] was low in Genesis836 but had increased markedly in Rupali. In Genesis836, Na was accumulated in epidermal cells but was low in mesophyll cells, whereas in Rupali cellular [Na] was high in both cell types. The excessive accumulation of Na in mesophyll cells of Rupali corresponded to structural damage to the chloroplasts. Maintenance of photosynthesis and thus salinity tolerance in Genesis836 was associated with an ability to ‘exclude’ Na from leaflets and in particular from the photosynthetically active mesophyll cells, and to compartmentalize Na in epidermal cells.


Development ◽  
1998 ◽  
Vol 125 (10) ◽  
pp. 1815-1822 ◽  
Author(s):  
E.A. Kinsman ◽  
K.A. Pyke

Bundle sheath cells form a sheath around the entire vascular tissue in Arabidopsis leaves and constitute a distinct leaf cell type, as defined by their elongate morphology, their position adjacent to the vein and by differences in their chloroplast development compared to mesophyll cells. They constitute about 15% of chloroplast-containing cells in the leaf. In order to identify genes which play a role in the differential development of bundle sheath and mesophyll cell chloroplasts, a screen of reticulate leaf mutants of Arabidopsis was used to identify a new class of mutants termed dov (differential development of vascular-associated cells). The dov1 mutant clearly demonstrates a cell-specific difference in chloroplast development. Mutant leaves are highly reticulate with a green vascular pattern. The underlying bundle sheath cells always contain normal chloroplasts, whereas chloroplasts in mesophyll cells are abnormal, reduced in number per cell and seriously perturbed in morphology at the ultrastructural level. This demonstrates that differential chloroplast development occurs between the bundle sheath and mesophyll cells in the Arabidopsis leaf.


Biologia ◽  
2006 ◽  
Vol 61 (1) ◽  
Author(s):  
Nikola Ljubešić ◽  
Mihaela Britvec

AbstractThe structural changes in leaves of grapevine plants (Vitis vinifera L.) exposed to different ozone concentrations were investigated. Ozone fumigations were performed in open-top chambers at four different ozone levels (charcoal-filtered air (F), ambient air (N), ambient air + 25 mm3m−3 ozone (O-25) and ambient air + 50 mm3m−3 ozone (O-50)).The leaves of plants from chambers with increased ozone concentrations (O-25 and O-50) were significantly thicker than the controls (F), owing to increased thickness of the mesophyll layer. Observing O-50 leaves, it was found that the mesophyll cell wall displayed structural changes. In some places cell wall thickness increased up to 1 µm. We found callose deposits on the inner side of the cell walls of mesophyll cells. These data are in accord with the concept that the mesophyll cell wall acts as a barrier against the penetration of tropospheric ozone into the cells.


Author(s):  
R.H.M. Cross ◽  
C.E.J. Botha ◽  
A.K. Cowan ◽  
B.J. Hartley

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.


Tsitologiya ◽  
2018 ◽  
Vol 60 (2) ◽  
pp. 128-135 ◽  
Author(s):  
L. M. Babenko ◽  
◽  
N. N. Scherbatiuk ◽  
D. A. Klimchuk ◽  
I. V. Kosakovskaya ◽  
...  

2014 ◽  
Vol 18 (5-6) ◽  
pp. 775-784 ◽  
Author(s):  
Sang Joon Lee ◽  
Hyejeong Kim ◽  
Sungsook Ahn

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