Ecotypic variation in forage nutrient value of a dominant grassland species,
Despite myriad examples of local adaptation, the phenotypes and genetic variants underlying such adaptive differentiation are seldom known. Recent work on freezing tolerance and local adaptation in ecotypes of
We examined the consequences of a naturally occurring loss‐of‐function (
Freezing tolerance was lower in the Italian (11%) compared to the Swedish (72%) ecotype, and all four experimental
We identified 10 genes that are at least partially regulated by
- NSF-PAR ID:
- 10458095
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- American Journal of Botany
- Volume:
- 107
- Issue:
- 2
- ISSN:
- 0002-9122
- Page Range / eLocation ID:
- p. 250-261
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Abstract Andropogon gerardii Vitman (big bluestem), was quantified across a longitudinal precipitation gradient of theUS Great Plains. Ecotypic variation ofA. gerardii has been documented across this gradient, but the extent to which forage nutrient value differs among ecotypes is poorly known. Seven indicators of forage nutrient value (neutral detergent fiber [NDF ], acid detergent fiber [ADF ],in‐vitro dry matter digestibility [IVDMD ], crude protein [CP ], crude fat [CF ], ash content) and relative feed value [RFV ] were examined in 12 populations representing four ecotypes corresponding with distinct climate regions: eastern Colorado, central Kansas, eastern Kansas and southern Illinois. Vegetative material ofA. gerardii was collected from each population in July 2010. A greenhouse study tested the effect of watering regime on seedlings of the ecotypes from three of the precipitation regions grown under controlled conditions. Forage nutrient value indicators nitrogen andCP increased, andADF decreased east to west, whileIVDMD decreased across the gradient corresponding with less annual precipitation. The greenhouse experiment showed that sampling before and after water treatment affected forage nutrient value measurements, with the exception ofNDF andCF . Nutrient value was most related to soil moisture and phenology, with smaller differences among ecotypes. Nutrient value of populations from the southern Illinois ecotype changed the least in response to variation in soil moisture. The southern Illinois ecotype will likely maintain forge nutrient value under variable precipitation projected to occur with climate change better than the ecotypes from more westerly parts of the range ofA. gerardii . -
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Premise Light is critical in the ability of plants to accumulate chlorophyll. When exposed to far‐red (
FR ) light and then grown in white light in the absence of sucrose, wild‐type seedlings fail to green in a response known as theFR block of greening (BOG ). This response is controlled by phytochrome A through repression of protochlorophyllide reductase‐encoding (POR ) genes byFR light coupled with irreversible plastid damage. Sigma (SIG ) factors are nuclear‐encoded proteins that contribute to plant greening and plastid development through regulating gene transcription in chloroplasts and impacting retrograde signaling from the plastid to nucleus.SIG s are regulated by phytochromes, and the expression of someSIG factors is reduced in phytochrome mutant lines, includingphyA . Given the association of phyA with theFR BOG and its regulation ofSIG factors, we investigated the potential regulatory role ofSIG factors in theFR BOG response.Methods We examined
FR BOG responses insig mutants, phytochrome‐deficient lines, and mutant lines for several phy‐associated factors. We quantified chlorophyll levels and examined expression of keyBOG ‐associated genes.Results Among six
sig mutants, only thesig6 mutant significantly accumulated chlorophyll afterFR BOG treatment, similar to thephyA mutant.SIG 6 appears to control protochlorophyllide accumulation by contributing to the regulation of tetrapyrrole biosynthesis associated with glutamyl‐tRNA reductase (HEMA 1) function, select phytochrome‐interacting factor genes (PIF4 andPIF6 ), andPENTA1 , which regulatesPORA mRNA translation afterFR exposure.Conclusions Regulation of
SIG6 plays a significant role in plant responses toFR exposure during theBOG response. -
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Premise Environmental sex determination (
ESD ) is a rare sex determination system in which individuals may switch sex expression throughout their lifetimes in response to environmental factors. In sexually stable species, individuals usually bear more female flowers if the plants are larger, have greater access to limiting resources, or are in better condition. Research regarding sexually plastic species withESD and how resources correlate with sex expression is limited. Furthermore, most research investigates resources at the population level, failing to account for resources available to individuals for growth, maintenance, or reproduction.Methods Acer pensylvanicum is a species that is known to switch sex. Using twig samples collected during 2014–2016 in December and May, we analyzed resource status in the form of stored nonstructural carbohydrates (NSC s) and compared this with expressed sex.Results We found that females had higher sugar concentrations than males. Furthermore, males changing expression to female had higher sugar concentrations during the prior winter than did males remaining male. We found that size was not a key predictor: neither male nor female‐flowering individuals increased
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Abstract Objective Previously, we found that diet‐induced
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HH cy, using pressure myography. Gap junction (Cx37, Cx40, Cx43),NOS (eNOS ,nNOS ,iNOS ), and potassium channel (IK 1) protein expression were measured with immunoblots, and connexinmRNA s with real‐timePCR . Contribution ofnNOS +iNOS to vasomotor responses was assessed using the drug TRIM.Results Myoendothelial feedback was significantly (
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