Xylem anatomy and function have large implications for plant growth as well as survival during drought, but the impact of nutrient limitation on xylem is not fully understood. This study examines the pygmy forest in California, a plant community that experiences negligible water stress but is severely stunted by low‐nutrient and acidic soil, to investigate how nutrient limitation affects xylem function. Thirteen key anatomical and hydraulic traits of stems of four species were compared between pygmy forest plants and nearby conspecifics growing on richer soil. Resistance to cavitation (P50), a critical trait for predicting survival during drought, had highly species‐specific responses: in one species, pygmy plants had a 26% decrease in cavitation resistance compared to higher‐nutrient conspecifics, while in another species, pygmy plants had a 56% increase in cavitation resistance. Other traits responded to nutrient limitation more consistently: pygmy plants had smaller xylem conduits and higher leaf‐specific conductivity ( Edaphic stress, even in the absence of water stress, altered xylem structure and thus had substantial impacts on water transport. Importantly, nutrient limitation shifted cavitation resistance in a species‐specific and unpredictable manner; this finding has implications for the assessment of cavitation resistance in other natural systems.
Understanding the genetic and physiological basis of abiotic stress tolerance under field conditions is key to varietal crop improvement in the face of climate variability. Here, we investigate dynamic physiological responses to water stress In conjunction with an ecophysiological process‐based model, heterogeneous data (plant hydraulic traits, spatially‐distributed soil texture, soil water content and canopy temperature) were used to examine hydraulic characteristics of cotton, evaluate their consequences on whole plant performance under drought, and explore potential genotype × environment effects. Cotton was found to have R‐shaped hydraulic vulnerability curves (VCs), which were consistent under drought stress initiated at flowering. Stem VCs, expressed as percent loss of conductivity, differed across genotypes, whereas root VCs did not. Simulation results demonstrated how plant physiological stress can depend on the interaction between soil properties and irrigation management, which in turn affect genotypic rankings of transpiration in a time‐dependent manner. Our study shows how a process‐based modeling framework can be used to link genotypic variation in hydraulic traits to differential acclimating behaviors under drought.
- PAR ID:
- 10368321
- Publisher / Repository:
- Wiley-Blackwell
- Date Published:
- Journal Name:
- New Phytologist
- Volume:
- 228
- Issue:
- 3
- ISSN:
- 0028-646X
- Page Range / eLocation ID:
- p. 898-909
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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