scholarly journals Reflectance continuum removal spectral index tracking the xanthophyll cycle photoprotective reactions in Norway spruce needles

2012 ◽  
Vol 39 (12) ◽  
pp. 987 ◽  
Author(s):  
Daniel Kováč ◽  
Martin Navrátil ◽  
Zbynĕk Malenovský ◽  
Michal Štroch ◽  
Vladimír Špunda ◽  
...  
Keyword(s):  
Norway Spruce ◽  
Spectral Index ◽  
Xanthophyll Cycle ◽  
High Irradiance ◽  
Carotenoid Content ◽  
Photon Flux ◽  
Dynamic Changes ◽  
Xanthophyll Cycle Pigments ◽  
Temperature Regimes ◽  
Band Depth

This laboratory experiment tested the ability of the spectral index called ‘area under curve normalised to maximal band depth’ (ANMB) to track dynamic changes in the xanthophyll cycle of Norway spruce (Picea abies (L.) Karsten) needles. Four-year-old spruce seedlings were gradually acclimated to different photosynthetic photon flux densities (PPFDs) and air temperature regimes. The measurements were conducted at the end of each acclimation period lasting for 11 days. A significant decline in the chlorophylls to carotenoids ratio and the increase of the amount of xanthophyll cycle pigments indicated a higher need for carotenoid-mediated photoprotection in spruce leaves acclimated to high PPFD conditions. Similarly, the photochemical reflectance index (PRI) changed from positive to negative values after changing light conditions from low to high intensity as a consequence of the increase in carotenoid content. Systematic responses of PRI to the de-epoxidation state of xanthophyll cycle pigments (DEPS) were, however, observed only during high temperature treatments and after the exposition of needles to high irradiance. The ANMB index computed from needle reflectance between 507 and 556 nm was able to track dynamic changes in DEPS without any influence induced by changing the content of leaf photosynthetic pigments (chlorophylls, carotenoids).

Effects of Temperature on Leaf Expansion in Sunflower

1982 ◽  
Vol 9 (2) ◽  
pp. 209 ◽  
Author(s):  
HM Rawson ◽  
JH Hindmarsh
Keyword(s):  
Field Studies ◽  
Leaf Expansion ◽  
Photon Flux ◽  
Photon Flux Density ◽  
Leaf Position ◽  
Leaf Emergence ◽  
Temperature Regimes ◽  
Effects Of Temperature ◽  
Increasing Temperature ◽  
Relative Change

Five commercial cultivars of sunflower were grown in cabinets at three temperature regimes, 32/22, 27/17 and 22/12°C, and with 15-h and 11-h photoperiods, and expansion of leaves 5-15 was followed. Leaves appeared faster with increasing temperature (0.022 leaves day-1 °C-1) and with increasing daylength. Areas of individual leaves increased linearly up the plant profile and, although final area per leaf (Amax) decreased with increasing temperature, the relative change was similar for each leaf position. Cultivars maintained their ranking for Amax across temperatures, and these rankings agreed with those in previous field studies. Within each temperature regime, both the expansion rate of leaves and the duration of expansion increased with leaf position. As temperature increased, leaves grew for shorter periods with a change of 1.04 days °C-1, but under the photon flux density used (500 �mol m-2 s-1, or about 25% full sunlight) expansion rates were greatest at the lowest temperature. Expansion rates were only one-third of those in field studies at comparable temperatures, but durations were similar. Cultivars that achieved the largest Amax did so via faster rates of expansion and not via longer durations: only one cultivar differed from the mean (20 days) duration of leaf expansion. All cultivars reached floral initiation progressively earlier with extension of photoperiod from 10 to 15 h, with the change for the most sensitive cultivars being 8 days and for the least sensitive 5 days. Rates of leaf emergence were linked with this sensitivity.

scholarly journals Glutathione and zeaxanthin formation during high light stress in foliose lichens

2008 ◽  
Vol 53 (No. 8) ◽  
pp. 340-344 ◽  
Author(s):  
J. Štepigová ◽  
H. Vráblíková ◽  
J. Lang ◽  
K. Večeřová ◽  
M. Barták
Keyword(s):  
Xanthophyll Cycle ◽  
Light Exposure ◽  
Light Stress ◽  
High Light ◽  
Short Term ◽  
Xanthophyll Cycle Pigments ◽  
High Light Stress ◽  
Fluorescence Label ◽  
Thiol Binding ◽  
Pure Acetone

In the presented study, we describe techniques for glutathione and pigment determination in lichens used in our laboratory. Glutathione and xanthophyll cycle pigments, especially zeaxanthin, are important antioxidants protecting plants against various stresses. In our laboratory, the high light stress in lichens has been intensively studied for several years. We extract glutathione in HCl and determine it by thiol-binding fluorescence label monobromobimane. For pigment determination, homogenized lichen thalli are extracted with pure acetone. According to our results, the total amount of glutathione decreases after a short-term high light exposure, while the amount of zeaxanthin increases.

Changes in light spectra modify secondary compound concentrations and BVOC emissions of Norway spruce seedlings

2020 ◽  
Author(s):  
Minna Kivimäenpää ◽  
Virpi Virjamo ◽  
Rajendra Prasad Ghimire ◽  
Jarmo Holopainen ◽  
Riitta Julkunen-Tiitto ◽  
...  
Keyword(s):  
Norway Spruce ◽  
Blue Light ◽  
White Light ◽  
Carbon Allocation ◽  
Light Emitting Diode ◽  
Abiotic Stress Tolerance ◽  
Photon Flux ◽  
Emission Rates ◽  
Light Emitting ◽  
Light Spectra

Our objective was to study how changes in the light spectra affects growth, carbohydrate, chlorophyll, carotenoid, terpene, alkaloid and phenolic concentrations, and BVOC (biogenic volatile organic compound) emissions of Norway spruce (Picea abies) seedlings. This study was conducted during the growth of the third needle generation in plant growth chambers. Two light spectra with the main difference in proportion of blue light (400-500 nm) and equal photon flux densities were provided by LED (light-emitting diode) lamps: 1) control (white light + 12 % blue light) and 2) increased blue light (+B) (white light + 45% blue light). The +B treatment increased needle concentrations of total flavonoids and acetophenones. The major changes in the phenolic profile were an accumulation of astragalin derivatives and the aglycone of picein. +B decreased concentrations of the main alkaloid compound, epidihydropinidine, and it’s precursor, 2-methyl-6-propyl-1,6-piperideine, emission rates of limonene, myrcene and total monoterpenes, and concentrations of a few terpenoid compounds, mainly in stems. Growth, needle carbohydrates and pigments were not affected. The results suggest that supplemental blue light shifts carbon allocation between secondary metabolism routes, from alkaloid and terpenoid synthesis to flavonoid and acetophenone synthesis. The changes may affect herbivory and abiotic stress tolerance of Norway spruce.

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