Rapid changes in cell wall pectic polysaccharides are closely associated with early stages of aerenchyma formation, a spatially localized form of programmed cell death in roots of maize (<i>Zea mays</i>L.) promoted by ethylene

Gunawardena, Arunika H. L. A. N.; Pearce, D. M. E.; Jackson, Michael B.; Hawes, Chris; Evans, David

doi:10.1046/j.1365-3040.2001.00774.x

Cited by 110 publications

(76 citation statements)

References 31 publications

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“…When the hypersensitive response is induced by pathogen invasion, the protoplast dies, leaving collapsed or crushed primary cell walls behind . By contrast, cell walls must be degraded to form the extensive lysigenous air spaces in hypoxiainduced aerenchyma tissues in maize and rice roots (He et al, 1994;Gunawardena et al, 2001aGunawardena et al, , 2001bKozela and Regan, 2003). Based on the pitted appearance of lace plant cell walls in scanning electron micrographs and the thinned and broken appearance in light and electron micrographs, we hypothesize that cell wall degradation is an integral part of PCD during leaf perforation in lace plant.…”

Section: Degradation Of Cytoplasm Nucleus and Cell Wallsmentioning

confidence: 96%

“…Although the primary signals that initiate the PCD pathway have not been identified for any of these cases, they are presumably internal and respond to positional and temporal cues elaborated during plant development. By contrast, environmentally induced PCD, such as the development of lysigenous aerenchyma triggered by hypoxic stress (Gunawardena et al, 2001a(Gunawardena et al, , 2001b and the hypersensitive response triggered by pathogen invasion (Ryerson and Heath, 1996;Heath, 2000), is initiated in response to abiotic or biotic external signals.…”

Section: Introductionmentioning

confidence: 99%

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Programmed Cell Death Remodels Lace Plant Leaf Shape during Development[W]

2004

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Programmed cell death (PCD) functions in the developmental remodeling of leaf shape in higher plants, a process analogous to digit formation in the vertebrate limb. In this study, we provide a cytological characterization of the time course of events as PCD remodels young expanding leaves of the lace plant. Tonoplast rupture is the first PCD event in this system, indicated by alterations in cytoplasmic streaming, loss of anthocyanin color, and ultrastructural appearance. Nuclei become terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling positive soon afterward but do not become morphologically altered until late stages of PCD. Genomic DNA is fragmented, but not into internucleosomal units. Other cytoplasmic changes, such as shrinkage and degradation of organelles, occur later. This form of PCD resembles tracheary element differentiation in cytological execution but requires unique developmental regulation so that discrete panels of tissue located equidistantly between veins undergo PCD while surrounding cells do not.

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Section: Degradation Of Cytoplasm Nucleus and Cell Wallsmentioning

confidence: 96%

Section: Introductionmentioning

confidence: 99%

Programmed Cell Death Remodels Lace Plant Leaf Shape during Development[W]

2004

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“…These are further transported via dictyosome or in individual vesicles and discharge through plasmalemma either directly or deposite accumulations in the vicinity of plasma membrane. In addition to changes in esterified and de-esterified pectins (Gunawardena et al 2001b), the role of other wall degrading enzymes including expansins, cellulases, xyloglucan endo-transglycosylase and pectinases has also been reported (Jackson and Armstrong 1999). It is likely that there are differences in the sensitivity of cells to the stimuli initiating cell death, whether hypoxia or ethylene or in subsequent response pathways.…”

Section: Ultrastructural Changes During Lysigenous Aerenchyma Formationmentioning

confidence: 99%

Lysigenous aerenchyma formation involves non-apoptotic programmed cell death in rice (Oryza sativa L.) roots

Joshi

Kumar

2011

Physiol Mol Biol Plants

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In waterlogged soil, deficiency of oxygen triggers development of aerenchyma in roots which facilitates gas diffusion between roots and the aerial environment. However, in contrast to other monocots, roots of rice (Oryza sativa L.) constitutively form aerenchyma even in aerobic conditions. The formation of cortical aerenchyma in roots is thought to occur by either lysigeny or schizogeny. Schizogenous aerenchyma is developed without cortical cell death. However, lysigenous gas-spaces are formed as a consequence of senescence of specific cells in primary cortex followed by their death due to autolysis. In the last stage of aerenchyma formation, a 'spoked wheel' arrangement is observed in the cortical region of root. Ultrastructural studies show that cell death is constitutive and no characteristic cell structural differentiation takes place in the dying cells with respect to surrounding cells. Cell collapse initiation occurs in the center of the cortical tissues which are characterized by shorter with radically enlarged diameter. Then, cell death proceeds by acidification of cytoplasm followed by rupturing of plasma membrane, loss of cellular contents and cell wall degradation, while cells nuclei remain intact. Dying cells releases a signal through symplast which initiates cell death in neighboring cells. During early stages, middle lamella-degenerating enzymes are synthesized in the rough endoplasmic reticulum which are transported through dictyosome and discharged through plasmalemma beneath the cell wall. In rice several features of root aerenchyma formation are analogous to a gene regulated developmental process called programmed cell death (PCD), for instance, specific cortical cell death, obligate production of aerenchyma under environmental stresses and early changes in nuclear structure which includes clumping of chromatin, fragmentation, disruption of nuclear membrane and apparent engulfment by the vacuole. These processes are followed by crenulation of plasma membrane, formation of electron-lucent regions in the cytoplasm, tonoplast disintegration, organellar swelling and disruption, loss of cytoplasmic contents, and collapse of cell. Many processes in lysing cells are structural features of apoptosis, but certain characteristics of apoptosis i.e., pycnosis of the nucleus, plasma membrane blebbing, and apoptotic bodies formation are still lacking and thus classified as non-apoptotic PCD. This review article, describes most recent observations alike to PCD involved in aerenchyma formation and their systematic distributions in rice roots.

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“…Chloroplast ultrastructure: Fresh leaves of chickpea collected were cut properly (2 mm), washed and then fixed in 2% para-formaldehyde, 1% glutaraldehyde, 0.1 M sodiun cacodylate buffer (pH 6.9) for 2 h at room temperature (Gunawardena et al, 2001). Leaf segments were washed in the buffer, and post-fixed in 1% aqueous osmium tetroxide for 1 h, before being stained in 0.5% uranyl acetate at 4°C overnight.…”

Section: Membrane Stability Indexmentioning

confidence: 99%

Bioregulators protected the leaf anatomy and photosynthetic machinery under water deficit stress in chickpea (Cicer arietinum L.)

Kumar

Singh

2016

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Water deficit is undoubtedly one of the most important environmental stresses limiting the productivity of chickpea around the world. Exogenous application of bioregulators has been found to be a novel technology for imparting stress tolerance in crop plants. This study evaluated the changes brought about by two bioregulators viz., thiourea (TU) and thidiazuron (TDZ) under water deficit stress in chickpea leaf anatomy, chloroplast ultrastructure and photosynthesis. The experiment was conducted using Pusa 362 (Desi type) chickpea variety. Imposed water deficit treatment decreased relative water content (RWC), membrane stability index (MSI) and photosynthetic rate (P N ). However, bioregulators application maintained higher RWC, MSI and P N under water deficit stress. Under imposed water stress, compact palisade layers of the mesophyll tissue were disrupted and cell size of the mesophyll cells displayed drastic reduction. Chloroplast, under water stress, displayed a number of grana with lose type of thylakoid, large increase in osmiophillic granules, reduction in the amount of starch granules and overall disruption of the thylakoid membrane. Foliar application of bioregulators maintained the integrity of mesophyll tissue and chloroplast structure thereby protected the chickpea plants from the detrimental effects of water deficit stress.

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Rapid changes in cell wall pectic polysaccharides are closely associated with early stages of aerenchyma formation, a spatially localized form of programmed cell death in roots of maize (Zea maysL.) promoted by ethylene

Abstract: ABSTRACT

Cited by 110 publications

References 31 publications

Programmed Cell Death Remodels Lace Plant Leaf Shape during Development[W]

Programmed Cell Death Remodels Lace Plant Leaf Shape during Development[W]

Lysigenous aerenchyma formation involves non-apoptotic programmed cell death in rice (Oryza sativa L.) roots

Bioregulators protected the leaf anatomy and photosynthetic machinery under water deficit stress in chickpea (Cicer arietinum L.)

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