Cytological changes in palisade cells of developing sunflower leaves

Fagerberg, Wayne R.

doi:10.1007/bf01287813

Cited by 18 publications

(9 citation statements)

References 23 publications

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“…In the parenchyma of older leaf primordia the relative volume of nuclei was significantly lower than in the younger primordia, while the relative volume of plastids increased with age. In a study on the development of sunflower leaves similar changes were found by Fagerberg (1984), when he compared leaves with a length of 10 and 45 mm, respectively.…”

Section: Discussionmentioning

confidence: 51%

Ultrastructure of dormant buds of Salix sp. in early winter

Berggren

1985

Nordic Journal of Botany

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Berggren, B. 1985. Ultrastructure of dormant buds of Sulix sp. in early winter. -Nord. J. Bot. 5: 475-488. Copenhagen. ISSN 0107-055X.In the apex of dormant buds of Sulk a histological zonation comparable to that found in growing buds was observed. However, significant changes in relative volumes of cell components between dormant and growing buds were noted; the dormant buds had a lower volume density of vacuoles and higher relative volumes of mitochondria, plastids, lipid bodies, and starch grains than the growing buds. In the leaf primordia the relative volume of nuclei decreased with age, while the relative volume of plastids and mitochondria increased. The large central vacuole found in cells of e.g. the procambium and rib meristem in growing buds is split into many smaller ones during the winter. A high content of tannin and calcium oxalate crystals was noted in dormant buds. They also accumulate lipids and starch. Phytoferritin may appear in plastids.Stacked ER and concentric sheaths of E R around lipid bodies appear, probably as a consequence of either anaerobic conditions or water stress. Several indications of metabolic activities in the seemingly dormant buds were found; plasmatubules at the plasmalemma particularly in the procambium, sheaths of smooth E R around the plastids, electron opaque globules (probably calcium-binding sites), and vacuoles that seemed to be autophagic.

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Section: Discussionmentioning

confidence: 51%

Ultrastructure of dormant buds of Salix sp. in early winter

Berggren

1985

Nordic Journal of Botany

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“…Proliferating cells grow primarily by an increase in the cytoplasmic volume, whereas cells in the postmitotic phase expand primarily through an increase in the vacuolar volume (Fagerberg, 1984). Thus, it is telling that a reduction in the relative elongation rate was of similar magnitude in both the division and elongation-only zones (30%-40%), raising the question of whether this was due to the same mechanism.…”

Section: Relative Elongation Rate Is Related To Phosphorus Statusmentioning

confidence: 95%

Phosphorus Deficiency Decreases Cell Division and Elongation in Grass Leaves

et al. 2006

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Leaf growth in monocotyledons results from the flux of newly born cells out of the division zone and into the adjacent elongation-only zone, where cells reach their final length. We used a kinematic method to analyze the effect of phosphorus nutrition status on cell division and elongation parameters in the epidermis of Lolium perenne. Phosphorus deficiency reduced the leaf elongation rate by 39% due to decreases in the cell production rate (219%) and final cell length (220%). The former was solely due to a lower average cell division rate (0.028 versus 0.046 cell cell 21 h 21 ) and, thus, a lengthened average cell cycle duration (25 versus 15 h). The number of division cycles of the initial cell progeny (five to six) and, as a result, the number of meristematic cells (32-64) and division zone length were independent of phosphorus status. Accordingly, low-phosphorus cells maintained meristematic activity longer. Lack of effect of phosphorus deficiency on meristematic cell length implies that a lower division rate was matched to a lower elongation rate. Phosphorus deficiency did not affect the elongation-only zone length, thus leading to longer cell elongation duration (99 versus 75 h). However, the substantially reduced postmitotic average relative elongation rate (0.045 versus 0.064 mm mm 21 h 21) resulted in shorter mature cells. In summary, phosphorus deficiency did not affect the general controls of cell morphogenesis, but, by slowing down the rates of cell division and expansion, it slowed down its pace.

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“…It still is an open question whether catalase is the structural (crystallized) component of cores and whether cores with different ultrastructures vary in protein composition. The function of cores in plant peroxisomes is not understood but a matter of speculation (Cronshaw 1965, Marinos 1965, Jensen and Valdovinos 1967, O'Brien and Thimann 1967, Fagerberg 1984, Tenberge and Eising 1995, Eising et al 1996. Knowledge of crystalline inclusions of plant peroxisomes is fragmentary mainly because no studies have ever been conducted on purified cores.…”

Section: Introductionmentioning

confidence: 98%

Purification and immuno-electron microscopical characterization of crystalline inclusions from plant peroxisomes

et al. 1997

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Summary. This paper describes the first purification method for crystalline inclusions (cores) from plant peroxisomes and an ultrastructural characterization of these isolated cores. 5-day-old sunflower (Helianthus annuus L.) cotyledon fractious which were highly enriched in cores showed negligible activity of the matrix enzyme glycolate oxidase but high catalase activity. As proven by electron microscopy, crystalline particles were surrounded neither by matrix material nor by membranes. Their geometrical outlines and ultrastructure were identical to those of cores in tissue sections, as was their reactivity with three different polyclonal catalase antibodies in the immunogold technique. Three-dimensional reconstruction, based on the geometrical outlines and ultrastructure of sectioned isolated cores from sunflower, suggested that they were quadrangular blocks. Ultrastructural analysis revealed an even periodic arrangement of repeating units which are probably cubes with 20 nm long edges. Isolated peroxisomal cores from potato (Solanum tuberosum L.) tubers had outlines which suggested that they were even rhomboidal prisms. They showed a granular ultrastructure without any repeating units and contained catalase, demonstrated by immunogold labelling and enzyme activity measurement. The results presented here suggested the hypothesis that the structural elements in plant peroxisomal cores are made of enzymatically active catalase, although the substructure may vary from species to species.

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Cytological changes in palisade cells of developing sunflower leaves

Cited by 18 publications

References 23 publications

Ultrastructure of dormant buds of Salix sp. in early winter

Ultrastructure of dormant buds of Salix sp. in early winter

Phosphorus Deficiency Decreases Cell Division and Elongation in Grass Leaves

Purification and immuno-electron microscopical characterization of crystalline inclusions from plant peroxisomes

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