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Waterlogging Signalling and Tolerance in Plants

:	Stefano Mancuso, Sergey Shabala
:	Stefano Mancuso, Sergey Shabala
:	Waterlogging Signalling and Tolerance in Plants
:	Springer-Verlag
:	9783642103056
:	1
:	CHF 198.80
:

:	Botanik
:	English

:	294
:	Wasserzeichen
:	PC/MAC/eReader/Tablet
:	PDF

In the last half century, because of the raising world population and because of the many environmental issues posed by the industrialization, the amount of arable land per person has declined from 0.32 ha in 1961-1963 to 0.21 ha in 1997-1999 and is expected to drop further to 0.16 ha by 2030 and therefore is a severe menace to food security (FAO 2006). At the same time, about 12 million ha of irrigated land in the developing world has lost its productivity due to waterlogging and salinity. Waterlogging is a major problem for plant cultivation in many regions of the world. The reasons are in part due to climatic change that leads to the increased number of precipitations of great intensity, in part to land degradation. Considering India alone, the total area suffering from waterlogging is estimated to be about 3.3 million ha (Bhattacharya 1992), the major causes of waterlogging include super- ous irrigation supplies, seepage losses from canal, impeded sub-surface drainage, and lack of proper land development. In addition, many irrigated areas are s- jected to yield decline because of waterlogging due to inadequate drainage systems. Worldwide, it has been estimated that at least one-tenth of the irrigated cropland suffers from waterlogging.

	Preface	5
	Contents	8
	Chapter 1: Oxygen Transport in Waterlogged Plants	19
	Introduction	20
	O2 Transport in Plants: Some Basic Physics, and Modelling of O2 Diffusion	21
	A Survey of Methods to Study O2 Transport and Related Parameters in Higher Plants	23
	Anatomical Adaptations to Flooding Stress: Barriers to Radial Oxygen Loss	26
	Anatomical Adaptations to Flooding Stress: Formation of Aerenchyma	27
	Mechanisms of O2 Transport in Plants	29
	O2 Transport in Plants: Ecological Implications	34
	Open Questions and Directions of Further Research	34
	References	35
	Chapter 2: Waterlogging and Plant Nutrient Uptake	39
	Introduction	39
	Effects of Hypoxia on Nutrient Uptake	42
	Physiological Effects of Hypoxia Change Root Elongation Rate, k, and Maximal Nutrient Uptake Rate, Imax	42
	Waterlogging Leads to Changes in the Availability, Cli, and the Effective Diffusion Coefficient, De, of Some of the Nutrients	44
	In Waterlogged Conditions, Some Plant Species Show More Root Hair Development, Longer and Thinner Roots and Increased Levels o	45
	Waterlogging Decrease Evaporation and Bulk Water Flow, Vo	46
	In Response to Waterlogging the Kinetics of Root Transport Systems, km and Imax, Can Be Modified	47
	Summary and Concluding Remarks	47
	References	48
	Chapter 3: Strategies for Adaptation to Waterlogging and Hypoxia in Nitrogen Fixing Nodules of Legumes	52
	Introduction: The Oxygen Diffusion BarrierOxygen Diffusion Barrier in Nodules	53
	Nodule Morphology and the Gas Diffusion Barrier	53
	Modulation of the Gas Diffusion Barrier	55
	Control of the Gas Diffusion Barrier in Response to Sub-Ambient O2 and Flooding	55
	Mechanism of Regulation of the Gas Diffusion Barrier in Response to pO2	56
	Developmental and Morphological Adaptations of Nitrogen-Fixing Nodules to Low Oxygen Stress	58
	Secondary AerenchymaSecondary Aerenchyma Formation	58
	The Inner CortexInner Cortex and Infected ZoneInfected Zone	59
	Influence of Adaptive Changes on Nitrogen Fixation Under Altered Rhizosphere pO2 Conditions	60
	Strategies of Adaptation: Flood-Tolerant Legumes and Oxygen Diffusion	61
	Tropical Wetland Legumeswetland legumes	61
	Nodulation of Submerged Stems and Roots: Increased Porosity Mechanisms	62
	Aerial Nodulation of Stems and Adventitious Roots: Avoidance Mechanisms	63
	Lotus uliginosus: A Temperate Wetland Legume	64
	Strategies of Adaptation: Alternate Nodulationnodulation Pathways for Flooding Tolerant Legumes	65
	Intercellular-Based Mechanism of Nodulation: The Lateral Root Boundary Pathway	65
	Sesbania rostrata: A Model Legume for Aquatic Nodulation	66
	Summary and Concluding Remarks	68
	References	70
	Chapter 4: Oxygen Transport in the Sapwood of Trees	75
	Brief Anatomy of a Woody Stem	76
	Atmosphere Inside a Stem: Gas Composition and its Effects on Respiration	77
	Gas Transport and Diffusion	80
	Radial and Axial Oxygen Transport to Sapwood	82
	Sapwood Respiration	84
	References	87
	Chapter 5: pH Signaling During Anoxia	91
	Introduction	91
	pH, Signal and Regulator	93
	pH as Systemic Signal	94
	The Nature of pH Transmission	95
	What is the Information?	95
	Anoxic Energy Crisis and pH Regulation	97
	The Davis-Roberts-Hypothesis: Aspects of pH Signaling	97
	Cytoplasmic Acidification, ATP and Membrane Potential	98
	Cytoplasmic pH (Change), An Error Signal?	99
	pH Interactions Between the (Major) Compartments During Anoxia	100
	The pH Trans-Tonoplast pH Gradient	100
	Cytoplasm and Apoplast	102
	The Apoplast Under Anoxia	102
	Anoxia Tolerance and pH	103
	pH as a Stress Signal - Avoidance of Cytoplasmic Acidosis	104
	pH as Signal for Gene Activation	105
	pH Signaling and Oxygen Sensing	106
	Conclusions	106
	References	107
	Chapter 6: Programmed Cell Death and Aerenchyma Formation Under Hypoxia	111
	Introduction	112
	Description of Aerenchyma Formation: Induced and Constitutive	114
	Evidence for PCD During Lysigenous Aerenchyma Formation	115
	Description of the Sequence of Events Leading to Induced Lysigenous Aerenchymalysigenous aerenchyma Formation	116
	Stimuli for Lysigenous Aerenchyma Development (Low Oxygen, Cytosolic Free Calciumfree calcium, Ethyl