scholarly journals Mechanism of Water Stress-Induced Xylem Embolism

1988 ◽  
Vol 88 (3) ◽  
pp. 581-587 ◽  
Author(s):  
John S. Sperry ◽  
Melvin T. Tyree
Keyword(s):  
Water Stress ◽  
Xylem Embolism

scholarly journals Root Severance at Harvest Increases Embolism and Decreases Sap Flow of Field-grown Acer rubrum L.

HortScience ◽  
2000 ◽  
Vol 35 (5) ◽  
pp. 833-836 ◽  
Author(s):  
Patricia R. Knight ◽  
J. Roger Harris ◽  
Jody K. Fanelli
Keyword(s):  
Water Stress ◽  
Stomatal Conductance ◽  
Sap Flow ◽  
Water Status ◽  
Acer Rubrum ◽  
Red Maple ◽  
Flow Sensors ◽  
Xylem Embolism ◽  
Sap Flow Sensors ◽  
Old Trees

Root severance during field harvesting alters the water status of a tree, resulting in water stress and reduced post-transplant growth. Two experiments, using Acer rubrum L. (red maple), determined the influence of root severance at harvest on sap flow and xylem embolism. Trees 1.5–1.8 m tall (4 years old) were utilized in the first experiment, and trees 1.2–1.5 m tall (2 years old) were utilized in the second. Sap flow sensors were installed on the 4-year-old trees prior to root severance and remained on the trees until 1 week after harvest. Within 1 day after root severance sap flow was reduced and remained lower than nontransplanted (control) trees for the remainder of the experiment. Leaf stomatal conductance (Cs) of transplanted trees 1 week after root severance was lower than that of control trees, but leaf water potentials (ψ) were similar. In the second experiment, sap flow was reduced relative to control trees within 2 h after root severance. Although Cs was reduced 4 hours after root severance, ψ was not. Embolism increased within 24 hours of root severance. These results indicate that root severance quickly induces increased levels of embolism, which is associated with reduced sap flow.

Water-stress-induced xylem embolism in three species of conifers

1990 ◽  
Vol 13 (5) ◽  
pp. 427-436 ◽  
Author(s):  
J. S. SPERRY ◽  
M. T. TYREE
Keyword(s):  
Water Stress ◽  
Xylem Embolism

scholarly journals Xylem embolism in leaves does not occur with open stomata: evidence from direct observations using the optical visualization technique

2019 ◽  
Vol 71 (3) ◽  
pp. 1151-1159 ◽  
Author(s):  
Danielle Creek ◽  
Laurent J Lamarque ◽  
José M Torres-Ruiz ◽  
Camille Parise ◽  
Regis Burlett ◽  
...  
Keyword(s):  
Water Stress ◽  
Stomatal Closure ◽  
Safety Margin ◽  
Carbon Assimilation ◽  
Xylem Embolism ◽  
Growth And Survival ◽  
Direct Observations ◽  
Optical Visualization ◽  
Embolism Resistance ◽  
The One

Abstract Drought represents a major abiotic constraint to plant growth and survival. On the one hand, plants keep stomata open for efficient carbon assimilation while, on the other hand, they close them to prevent permanent hydraulic impairment from xylem embolism. The order of occurrence of these two processes (stomatal closure and the onset of leaf embolism) during plant dehydration has remained controversial, largely due to methodological limitations. However, the newly developed optical visualization method now allows concurrent monitoring of stomatal behaviour and leaf embolism formation in intact plants. We used this new approach directly by dehydrating intact saplings of three contrasting tree species and indirectly by conducting a literature survey across a greater range of plant taxa. Our results indicate that increasing water stress generates the onset of leaf embolism consistently after stomatal closure, and that the lag time between these processes (i.e. the safety margin) rises with increasing embolism resistance. This suggests that during water stress, embolism-mediated declines in leaf hydraulic conductivity are unlikely to act as a signal for stomatal down-regulation. Instead, these species converge towards a strategy of closing stomata early to prevent water loss and delay catastrophic xylem dysfunction.

scholarly journals Soil water-holding capacity mediates hydraulic and hormonal signals of near-isohydric and near-anisohydric Vitis cultivars in potted grapevines

2014 ◽  
Vol 41 (11) ◽  
pp. 1119 ◽  
Author(s):  
Sara Tramontini ◽  
Johanna Döring ◽  
Marco Vitali ◽  
Alessandra Ferrandino ◽  
Manfred Stoll ◽  
...  
Keyword(s):  
Water Stress ◽  
Soil Water ◽  
Stomatal Closure ◽  
Vitis Vinifera L ◽  
Cabernet Sauvignon ◽  
Xylem Embolism ◽  
Early Stress ◽  
Growing Conditions ◽  
Response To Water ◽  
Water Holding

Grapevine (Vitis vinifera L.) expresses different responses to water stress, depending not only on genotype, but also on the influence of vineyard growing conditions or seasonality. Our aim was to analyse the effects on drought response of two grapevine cultivars growing on two soils, one water draining (WD) containing sand 80% volume and the other water retaining (WR), with no sand. Under these two different water-holding capacities Syrah, displaying a near-anisohydric response to water stress, and Cabernet Sauvignon (on the contrary, near-isohydric) were submitted to water stress in a pot trial. Xylem embolism contributed to plant adaptation to soil water deprivation: in both cultivars during late phases of water stress, however, in Syrah, already at moderate early stress levels. By contrast, Syrah showed a less effective stomatal control of drought than Cabernet Sauvignon. The abscisic acid (ABA) influenced tightly the stomatal conductance of Cabernet Sauvignon on both pot soils. In the near-anisohydric variety Syrah an ABA-related stomatal closure was induced in WR soil to maintain high levels of water potential, showing that a soil-related hormonal root-to-shoot signal causing stomatal closure superimposes on the putatively variety-induced anisohydric response to water stress.

Biscogniauxia (Hypoxylon) Canker or Dieback in Trees

EDIS ◽  
2017 ◽  
Vol 2017 (6) ◽  
Author(s):  
Claudia Paez ◽  
Jason A. Smith
Keyword(s):  
Water Stress ◽  
Tree Species ◽  
Soil Compaction ◽  
Urban Areas ◽  
Root Disease ◽  
Poor Health ◽  
Green Spaces ◽  
Opportunistic Pathogens ◽  
Wide Range ◽  
Quercus Spp

Biscogniauxia canker or dieback (formerly called Hypoxylon canker or dieback) is a common contributor to poor health and decay in a wide range of tree species (Balbalian & Henn 2014). This disease is caused by several species of fungi in the genus Biscogniauxia (formerly Hypoxylon). B. atropunctata or B. mediterranea are usually the species found on Quercus spp. and other hosts in Florida, affecting trees growing in many different habitats, such as forests, parks, green spaces and urban areas (McBride & Appel, 2009).  Typically, species of Biscogniauxia are opportunistic pathogens that do not affect healthy and vigorous trees; some species are more virulent than others. However, once they infect trees under stress (water stress, root disease, soil compaction, construction damage etc.) they can quickly colonize the host. Once a tree is infected and fruiting structures of the fungus are evident, the tree is not likely to survive especially if the infection is in the tree's trunk (Anderson et al., 1995).

Citrus Irrigation Management

EDIS ◽  
2017 ◽  
Vol 2017 (5) ◽  
Author(s):  
Davie Mayeso Kadyampakeni ◽  
Kelly T. Morgan ◽  
Mongi Zekri ◽  
Rhuanito Ferrarezi ◽  
Arnold Schumann ◽  
...  
Keyword(s):  
Water Stress ◽  
Physiological Activity ◽  
Irrigation Management ◽  
Fruit Size ◽  
Irrigation Scheduling ◽  
Leaf Expansion ◽  
Tree Canopy ◽  
Limiting Factor ◽  
Irrigation Frequency ◽  
Citrus Production

Water is a limiting factor in Florida citrus production during the majority of the year because of the low water holding capacity of sandy soils resulting from low clay and the non-uniform distribution of the rainfall. In Florida, the major portion of rainfall comes in June through September. However, rainfall is scarce during the dry period from February through May, which coincides with the critical stages of bloom, leaf expansion, fruit set, and fruit enlargement. Irrigation is practiced to provide water when rainfall is not sufficient or timely to meet water needs. Proper irrigation scheduling is the application of water to crops only when needed and only in the amounts needed; that is, determining when to irrigate and how much water to apply. With proper irrigation scheduling, yield will not be limited by water stress. With citrus greening (HLB), irrigation scheduling is becoming more important and critical and growers cannot afford water stress or water excess. Any degree of water stress or imbalance can produce a deleterious change in physiological activity of growth and production of citrus trees.  The number of fruit, fruit size, and tree canopy are reduced and premature fruit drop is increased with water stress.  Extension growth in shoots and roots and leaf expansion are all negatively impacted by water stress. Other benefits of proper irrigation scheduling include reduced loss of nutrients from leaching as a result of excess water applications and reduced pollution of groundwater or surface waters from the leaching of nutrients. Recent studies have shown that for HLB-affected trees, irrigation frequency should increase and irrigation amounts should decrease to minimize water stress from drought stress or water excess, while ensuring optimal water availability in the rootzone at all times.

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