Effects of growth temperature and winter duration on leaf longevity were compared between a spring ephemeral, Gagea lutea, and a forest summergreen forb, Maianthemum dilatatum. The plants were grown at day/night temperatures of 25/20 degrees C and 15/10 degrees C after a chilling treatment for variable periods at 2 degrees C. The temperature regime of 25/20 degrees C was much higher than the mean air temperatures for both species in their native habitats. Warm temperature of 25/20 degrees C and/or long chilling treatment shortened leaf longevity in G. lutea, but not in M. dilatatum. The response of G. lutea was consistent with that reported for other spring ephemerals. Air temperature increases as the vegetative season progresses. The decrease in leaf longevity in G. lutea under warm temperature condition ensures leaf senescence in summer, an unfavorable season for its growth. This also implies that early leaf senescence could occur in years with early summers. Warm spring temperatures have been shown to accelerate the leafing-out of forest trees. The decrease in leaf longevity due to warm temperature helps synchronize the period of leaf senescence roughly with the time of the forest canopy leaf-out. Prolonged winter due to late snowmelt has been shown to shorten the vegetative period for spring ephemerals. The decrease in leaf longevity due to long chilling treatment would correspond with this shortened vegetative period.
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http://dx.doi.org/10.1007/s10265-008-0173-9 | DOI Listing |
J Environ Manage
December 2024
School of Earth Ocean and Climate Sciences, Indian Institute of Technology Bhubaneswar, Argul, Khorda, Odisha, India.
This study assessed the influence of anthropogenic short-term nutrient enrichment (hereafter enriched) effects on seagrass population dynamics (recruitment, growth rate and mortality), morphometric traits, productivity, and leaf biodiversity assemblages in the islands of Andaman and Nicobar (ANI) of India and contrasted these findings with away from these enriched areas (hereafter pristine). Seagrass (Thalassia hemprichii and Cymodocea rotundata), and sediment samples were collected in the dry season (October-May) of ANI. Reconstruction techniques, an indirect measurement of plant growth was used to derive leaf plastochrone interval (PI), i.
View Article and Find Full Text PDFActa Trop
December 2024
Departamento de Ecología, Genética y Evolución, Facultad de Ciencias Exactas y Naturales, Instituto IEGEBA (CONICET-UBA), Universidad de Buenos Aires, Ciudad Universitaria, Pabellón 2, 4to piso. Laboratorio 54. C1428EHA, Buenos Aires, Argentina.
The performance of Aedes aegypti was evaluated under natural winter nutritional and thermal conditions in the temperate region of Argentina. Immature stages were reared using leaf litter as a food source. The rearing was structured in three cohorts, the first started in late-fall, the second in early-winter and the last in mid-winter, and in each cohort two treatments were arranged according to solar exposure (sun and shade).
View Article and Find Full Text PDFPlant Physiol Biochem
December 2024
Institute of Ecology and Environmental Sciences of Paris (iEES Paris), Univ Paris Est Creteil, CNRS, INRAE, IRD, IEES, F-94010, Creteil, France. Electronic address:
Current background tropospheric ozone (O) concentrations have significant adverse effects on wheat. O generally induces oxidative damages and premature leaf senescence leading to important yield losses. As leaf protein degradation and recycling is involved in both maintaining cell longevity during abiotic stresses and performing efficient nitrogen remobilization during senescence, we aimed to identify proteases involved in acidic endoproteolytic activities during natural and O-induced leaf senescence in wheat.
View Article and Find Full Text PDFEcotoxicology
December 2024
Departamento de Entomologia, Universidade Federal de Viçosa, Viçosa, MG, Brazil.
Agricultural insecticide usage presents a complex challenge, particularly when addressing hidden targets such as concealed pest species. Typically, insecticide spraying targets either the host plant or the soil substrate, reaching the target when the pests move or feed, yet their vulnerability when concealed remains low. This study delves into the often-obscure effects of insecticides on hidden herbivore species, focusing specifically on the diamide insecticide chlorantraniliprole and its impact on the concealed insect herbivore, the coffee leaf miner Leucoptera coffeella (Guérin-Mèneville & Perrottet) (Lepidoptera: Lyonetidae).
View Article and Find Full Text PDFProc Natl Acad Sci U S A
November 2024
Tianjin Key Laboratory of Protein Sciences, Department of Plant Biology and Ecology, College of Life Sciences, Nankai University, Tianjin 300071, China.
Ethylene is widely recognized as a positive regulator of leaf senescence. However, how plants coordinate the biosynthesis of ethylene to meet the requirements of senescence progression has not been determined. The rate-limiting enzyme in the ethylene biosynthesis pathway is ACC synthase.
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