Conifers and broadleaf species: stomatal sensitivity differs in western Oregon

Increasing stomatal closure was exhibited by two conifer and six broadleaf species as vapor pressure deficit increased. Conifers were more sensitive to high vapor pressure deficit than were the broadleaved species. One shrub, snowbrush (Ceanothusvelutinus Dougl. ex Hook.), exhibited no stomatal closure as vapor pressure deficit increased. These traits, when interpreted in terms of known soil moisture depletion patterns, help explain why broadleaved species initially colonize disturbed areas in western Oregon, but are later replaced by long-lived conifers.

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Stomatal closure induced by high vapor pressure deficit limited midday photosynthesis at the canopy top of Fagus crenata Blume on Naeba mountain in Japan

Trees ◽

10.1007/s00468-004-0327-x ◽

2004 ◽

Vol 18 (5) ◽

Cited By ~ 19

Author(s):

Atsuhiro Iio ◽

Hisakazu Fukasawa ◽

Yachiho Nose ◽

Yoshitaka Kakubari

Keyword(s):

Vapor Pressure ◽

Vapor Pressure Deficit ◽

Stomatal Closure ◽

Fagus Crenata ◽

High Vapor Pressure ◽

Fagus Crenata Blume ◽

High Vapor

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Land–atmosphere feedbacks exacerbate concurrent soil drought and atmospheric aridity

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1904955116 ◽

2019 ◽

Vol 116 (38) ◽

pp. 18848-18853 ◽

Cited By ~ 34

Author(s):

Sha Zhou ◽

A. Park Williams ◽

Alexis M. Berg ◽

Benjamin I. Cook ◽

Yao Zhang ◽

...

Keyword(s):

Soil Moisture ◽

Vapor Pressure ◽

High Probability ◽

Vapor Pressure Deficit ◽

Cmip5 Models ◽

Soil Drought ◽

Global Land ◽

High Vapor ◽

Mean Climate ◽

Negative Coupling

Compound extremes such as cooccurring soil drought (low soil moisture) and atmospheric aridity (high vapor pressure deficit) can be disastrous for natural and societal systems. Soil drought and atmospheric aridity are 2 main physiological stressors driving widespread vegetation mortality and reduced terrestrial carbon uptake. Here, we empirically demonstrate that strong negative coupling between soil moisture and vapor pressure deficit occurs globally, indicating high probability of cooccurring soil drought and atmospheric aridity. Using the Global Land Atmosphere Coupling Experiment (GLACE)-CMIP5 experiment, we further show that concurrent soil drought and atmospheric aridity are greatly exacerbated by land–atmosphere feedbacks. The feedback of soil drought on the atmosphere is largely responsible for enabling atmospheric aridity extremes. In addition, the soil moisture–precipitation feedback acts to amplify precipitation and soil moisture deficits in most regions. CMIP5 models further show that the frequency of concurrent soil drought and atmospheric aridity enhanced by land–atmosphere feedbacks is projected to increase in the 21st century. Importantly, land–atmosphere feedbacks will greatly increase the intensity of both soil drought and atmospheric aridity beyond that expected from changes in mean climate alone.

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Mucilage Polysaccharide Composition and Exudation in Maize From Contrasting Climatic Regions

Frontiers in Plant Science ◽

10.3389/fpls.2020.587610 ◽

2020 ◽

Vol 11 ◽

Author(s):

Meisam Nazari ◽

Sophie Riebeling ◽

Callum C. Banfield ◽

Asegidew Akale ◽

Margherita Crosta ◽

...

Keyword(s):

Vapor Pressure ◽

Vapor Pressure Deficit ◽

Genetic Material ◽

Root Tips ◽

High Vapor Pressure ◽

Climatic Regions ◽

Randomized Field Experiment ◽

Neutral Sugars ◽

High Vapor ◽

Polysaccharide Composition

Mucilage, a gelatinous substance comprising mostly polysaccharides, is exuded by maize nodal and underground root tips. Although mucilage provides several benefits for rhizosphere functions, studies on the variation in mucilage amounts and its polysaccharide composition between genotypes are still lacking. In this study, eight maize (Zea mays L.) genotypes from different globally distributed agroecological zones were grown under identical abiotic conditions in a randomized field experiment. Mucilage exudation amount, neutral sugars and uronic acids were quantified. Galactose (∼39–42%), fucose (∼22–30%), mannose (∼11–14%), and arabinose (∼8–11%) were the major neutral sugars in nodal root mucilage. Xylose (∼1–4%), and glucose (∼1–4%) occurred only in minor proportions. Glucuronic acid (∼3–5%) was the only uronic acid detected. The polysaccharide composition differed significantly between maize genotypes. Mucilage exudation was 135 and 125% higher in the Indian (900 M Gold) and Kenyan (DH 02) genotypes than in the central European genotypes, respectively. Mucilage exudation was positively associated with the vapor pressure deficit of the genotypes’ agroecological zone. The results indicate that selection for environments with high vapor pressure deficit may favor higher mucilage exudation, possibly because mucilage can delay the onset of hydraulic failure during periods of high vapor pressure deficit. Genotypes from semi-arid climates might offer sources of genetic material for beneficial mucilage traits.

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