Photosynthesis is a highly integrated and regulated process which sensitive to any change in environmental conditions, because it needs balance the light energy absorbed by photosystems with consumed metabolic sinks of plant. Low temperatures exacerbate an imbalance between source sink, thus requiring adjustments photosynthesis maintain flow. itself functions as sensor this through redox state photosynthetic electron‐transport components regulates photophysical, photochemical processes...

In evergreen conifers, where the foliage amount changes little with season, accurate detection of underlying "photosynthetic phenology" from satellite remote sensing has been difficult, presenting challenges for global models ecosystem carbon uptake. Here, we report a close correspondence between seasonally changing foliar pigment levels, expressed as chlorophyll/carotenoid ratios, and photosynthetic activity, leading to "chlorophyll/carotenoid index" (CCI) that tracks photosynthesis at...

Abstract During winter and early spring, evergreen boreal conifers are severely stressed because light energy cannot be used when photosynthesis is pre‐empted by low ambient temperatures. To study photosynthetic performance dynamics in a severe climate, seasonal changes pigments, chloroplast proteins photochemical efficiency were studied Scots pine forest near Zotino, Central Siberia. In winter, downregulation of involved loss chlorophylls, twofold increase xanthophyll cycle pigments...

The ability of plants to sequester carbon is highly variable over the course year and reflects seasonal variation in photosynthetic efficiency. This most prominent during autumn, when leaves deciduous tree species such as sugar maple (Acer saccharum Marsh.) undergo senescence, which associated with downregulation photosynthesis a change leaf color. remote sensing color by spectral reflectance measurements digital repeat images increasingly used improve models growing season length...

Summary Phenology is an important indicator of environmental variation and climate change impacts on tree responses. In conifers, monitoring phenology photosynthesis through remote sensing has been unreliable, because needle foliage varies little throughout the year. This challenging for modelling ecosystem carbon uptake enhanced breeding (genomic selection) forest health. Here, we demonstrate that drone‐based carotenoid‐sensitive spectral indices, such as Chl/carotenoid index (CCI), can be...

Summary Photosynthetic phenology is an important indicator of annual gross primary productivity (GPP). Assessing photosynthetic remotely difficult for evergreen conifers as they remain green year‐round. Carotenoid‐based vegetation indices such the photochemical reflectance index (PRI) and chlorophyll/carotenoid (CCI) are promising tools to track invisible photosynthesis by assessing carotenoid pigment dynamics. PRI, CCI near‐infrared (NIR V ) may act proxies efficiency ( ɛ ), parameter in...

Abstract Monitoring early tree physiological responses to drought is key understanding progressive impacts of on forests and identifying resilient species. We combined drone‐based multispectral remote sensing with measurements physiology environmental parameters over two growing seasons in a 100‐y‐old Pinus sylvestris forest subject 17‐y precipitation manipulation. Our goal was determine if photochemical reflectance index (PRI) captures stress whether are affected by long‐term acclimation....

In the past, role of light as an energy source was largely ignored in research focused on cold acclimation and freezing tolerance plants. However, is energy-requiring process. We summarize illustrating that photoautrophs diverse cyanobacteria (Plectonema boryanum), green algae (Chlorella vulgaris, Dunaliella salina, Chlamydomonas raudensis), crop plants (Triticum aestivum L., Secale cereale Brassica napus L.), conifers (Pinus banksiana) L.) tailor structure function photosynthetic apparatus...

Douglas fir (Pseudotsuga menziesii) is a conifer species that stores large amounts of terpenoids, mainly monoterpenoids in resin ducts various tissues. The effects drought on stored leaf terpenoid concentrations trees are scarcely studied and published data partially controversial, since reduced, unaffected or elevated contents due to have been reported. Even less known the effect root terpenoids. In present work, we investigated reduced water availability content roots needles seedlings....

• An earlier onset of photosynthesis in spring for boreal forest trees is predicted as the climate warms, yet importance soil vs air temperatures recovery remains to be determined. Effects various soil- and air-temperature conditions on Scots pine (Pinus sylvestris) seedlings were assessed under controlled environmental conditions. Using winter-acclimated seedlings, photosynthetic responses followed after transfer different simulated Recovery rates electron transport net CO2 uptake slower...

Temperature and daylength act as environmental signals that determine the length of growing season in boreal evergreen conifers. Climate change might affect seasonal development these trees, they will experience naturally decreasing during autumn, while at same time warmer air temperature maintain photosynthesis respiration. We characterized down-regulation photosynthetic gas exchange mechanisms involved dissipation energy Jack pine (Pinus banksiana) controlled environments a simulated...

Leaf reflectance spectral measurements are an emerging non-invasive technique that can be used to derive the photochemical index (PRI) assess physiological state of plants from leaf ecosystem level. Changes in PRI associated with changes xanthophyll cycle activity and provide estimate effective quantum efficiency (ΦII) during growing season. However, we hypothesised correlation between ΦII might poor when is primed for sustained thermal dissipation light energy absorbed. To test our...

Drought is a major environmental stress affecting growth and vitality of forest ecosystems. In the present study, foliar nitrogen (N) carbon (C) metabolism two Douglas fir (Pseudotsuga menziesii) provenances with assumed different drought tolerance were investigated. We worked 1-year-old seedlings interior provenance Fehr Lake (FEHR) originating from dry environment coastal Snoqualmie (SNO) more humid origin. Total C N, structural N concentrations soluble protein, total amino acids (TAAs)...

We studied the influence of two irradiances on cold acclimation and recovery photosynthesis in Scots pine (Pinus sylvestris L.) seedlings to assess mechanisms for quenching excess energy captured by photosynthetic apparatus. A shift temperature from 20 5 degrees C caused a greater decrease activity, measured chlorophyll fluorescence oxygen evolution, plants exposed moderate light (350 micromol m(-2) s(-1)) than shaded (50 s(-1)). In response shift, maximal photochemical efficiency...

Photosynthesis in evergreen conifers is characterized by down-regulation autumn and rapid up-regulation spring. This seasonal pattern largely driven temperature, but the light environment also plays a role. In overwintering Scots pine (Pinus sylvestris L.) trees, PSII less down-regulated recovers faster from winter stress shaded needles than exposed to full sunlight. Because effect of on acclimation has not been quantitatively studied under field conditions, we used rate constants for...

In evergreen conifers, the winter down-regulation of photosynthesis and its recovery during spring are result a reorganization chloroplast adjustments energy-quenching mechanisms. These phenological changes may remain undetected by remote sensing, as conifers retain green foliage periods photosynthetic down-regulation. The aim was to assess if timing characteristics accurately monitored photochemical reflectance index (PRI) in conifer Pinus strobus. studied using chlorophyll fluorescence,...

The photochemical reflectance index (PRI) is a proxy for the activity of photoprotective xanthophyll cycle and photosynthetic light use efficiency (LUE) in plants. Evergreen conifers downregulate photosynthesis autumn response to low temperature shorter photoperiod, dynamic cycle-mediated non-photochemical quenching (NPQ) replaced by sustained NPQ. We hypothesized that this shift cycle-dependent energy partitioning during cause variations PRI–LUE relationship. In order test our hypothesis,...

Local adaptation and phenotypic plasticity are important components of plant responses to variations in environmental conditions. While local has been widely studied trees, little is known about gene expression adult trees response ever changing conditions natural habitats. Here we investigate needle tissue between two Douglas-fir provenances represented by 25 using deep RNA sequencing (RNA-Seq).

Abstract Diurnal patterns of photosynthesis were studied in July and April populations Cladophora glomerata (L.) Kütz. from open shaded sites. Summer samples exposed to full sunlight showed decreased efficiency photosystem II at noon, only slight differences found between that had grown or Electron transport rate was limited highest fluence rates shade plants, non‐photochemical quenching (NPQ) revealed faster regulation Daily course de‐epoxidation not linearly correlated with the NPQ. The...