Biochemical and functional characteristics of the photosynthetic apparatus in vegetative buds and mature needles of Norway spruce (Picea abies L. Karst.)

The biochemical characteristics and functioning of the photosynthetic apparatus in two developmental stages of spruce needles (vegetative buds and mature needles) were compared. Biochemical analysis included quantification of the photosynthetic pigments and immunodetection of the NAPDH-protochlorophyllide oxidoreductase (POR). Photosynthetic performance was monitored as the oxygen production at different light levels applied. Two POR isoforms were detected in buds while only one isoform was present in mature needles. The POR polypeptides in buds were expressed at different levels: the polypeptide of lower molecular mass had a level that was more enhanced than that of higher molecular mass. The most intensive POR signal was observed in mature needles. Concentrations of chlorophylls and carotenoids that were higher in mature needles than in vegetative buds were in accordance with observed POR expression. This reflected on the photosynthetic activity of the investigated organs. Although the chloroplasts in vegetative buds revealed the capability of photosynthesising, the compensation of respiration was not observed even at the highest light level (1100 molPHOTONS m–2s–1) applied. In contrast, mature needles ompensated for respiration successfully at low light level (30 molPHOTONS m–2s–1). Our study showed that chloroplasts in vegetative buds are photosynthetically competent, but limited by their molecular and biochemical background

The effect of 2,4-D on the photosynthetic apparatus in cotyledons of spruce (Picea abies L. Karst.) seedlings grown in the dark

Growth regulating substance, 2,4-dichlorophenoxyacetic acid (2,4-D) is widely used in plant cell cultures and also in agriculture as a herbicide. The effect of 2,4-D on photosynthetic pigment content and chloroplast ultrastructure in spruce seedlings grown in the dark was studied. Seedlings were grown for 16 days in the dark at room temperature in Petri dishes moistened either with tap water (control) or 4.5, 45 and 450 μM 2,4-D. The lowest concentration (4.5 μM) of 2,4-D induced both chlorophyll and carotenoid biosynthesis as compared to the control treatment. There were no statistically significant differences in any of the measured parameters between the control and the 45 μM 2,4-D treatment. A herbicidal concentration of 2,4-D (450 μM) induced a decline in chlorophyll content, while carotenoids were not significantly influenced. In contrast to the low concentration treatments, a herbicidal concentration of 2,4-D caused extensive changes in chloroplast shape and ultrastructure

The annual changes of chloroplast pigments content in current- and previous-year needles of Norway spruce (Picea abies L. Karst.) exposed to cement dust pollution

Chloroplast pigments were shown to be very sensitive to various environmental influences. Changes in chlorophyll and carotenoid content were investigated in Norway spruce needles exposed to alkaline dust emitted by the cement industry. Pigments were extracted from current-year and previous-year needles and quantified spectrophotometrically. In both needle generations all measured pigments were reduced in dust-exposed needles compared to needles harvested from areas not polluted by cement dust. This was due to deceleration of the biosynthetic processes rather than degradation of pigments. Chlorophyll b content appeared to be more sensitive than chlorophyll a in current-year needles while in previous-year needles chlorophyll a was more affected. Total carotenoids needed a longer period of time to reach nearly the same level as in controls. The progression of pigment decline in previous-year needles appeared not to be dramatically accelerated. It might thus be concluded that the spruce needles had sufficient biosynthetic capacity to prevent irreversible damage by cement dust

Utjecaj promijenjene mineralne ishrane na iglice Pančićeve omorike (Picea omorika Pančić) – istraživanje pojedinačnog slučaja

A widespread conifer forest decline in Europe and North America has been expressed through various combinations of symptoms. In our study, unspecific biochemical indicators and histological findings were compared with visually assessed damage symptoms in order to get a detailed diagnosis of a single declining Picea omorika Pančić tree. By measuring the content of photosynthetic pigments and proteins as well as total guaiacol peroxidase activity we confirmed an altered physiological state of the investigated tree. Histological analysis showed specific patterns of decline for Mg and K deficient trees.Sveprisutno propadanje šuma u Europi i sjevernoj Americi manifestira se kao kombinacija različitih simptoma. U provedenom istraživanju usporedili smo nespecifične biokemijske indikatore i histološke nalaze s vizualnom procjenom oštećenja, a s ciljem postavljanja detaljne dijagnoze propadanja jednog stabla Pančićeve omorike (Picea omorika Pančić). Odre|ivanjem sadržaja fotosintetskih pigmenata, proteina i aktivnosti ukupnih gvajacilnih peroksidaza potvr|ena je promjena fiziološkog statusa biljke. Histološke analize pokazale su specifičnosti karakteristične za stabla deficijentna magnezijem i kalijem

Utjecaj promijenjene mineralne ishrane na iglice Pančićeve omorike (Picea omorika Pančić) – istraživanje pojedinačnog slučaja

A widespread conifer forest decline in Europe and North America has been expressed through various combinations of symptoms. In our study, unspecific biochemical indicators and histological findings were compared with visually assessed damage symptoms in order to get a detailed diagnosis of a single declining Picea omorika Pančić tree. By measuring the content of photosynthetic pigments and proteins as well as total guaiacol peroxidase activity we confirmed an altered physiological state of the investigated tree. Histological analysis showed specific patterns of decline for Mg and K deficient trees.Sveprisutno propadanje šuma u Europi i sjevernoj Americi manifestira se kao kombinacija različitih simptoma. U provedenom istraživanju usporedili smo nespecifične biokemijske indikatore i histološke nalaze s vizualnom procjenom oštećenja, a s ciljem postavljanja detaljne dijagnoze propadanja jednog stabla Pančićeve omorike (Picea omorika Pančić). Odre|ivanjem sadržaja fotosintetskih pigmenata, proteina i aktivnosti ukupnih gvajacilnih peroksidaza potvr|ena je promjena fiziološkog statusa biljke. Histološke analize pokazale su specifičnosti karakteristične za stabla deficijentna magnezijem i kalijem

Utjecaj temperature pohranjivanja na aktivnost ukupnih peroksidaza u nepročišćenom ekstraktu iglica smreke (Picea abies L. Karst.)

Peroxidases are enzymes with numerous functions in plant cells and are, therefore, interesting objects of current biochemical research. The purpose of this work was to investigate the effect of 30 days storage at different temperatures on the peroxidase activity in crude extracts from one-year old needles of Picea abies L. Karst. Total peroxidase activity was detected in the extract reaction with guaiacol and H2O2. Colour product was quantified by absorbance measurement at 470 nm. Measurements were performed daily in the first 10 days, and on the 12th, 14th, 16th, 18th and 30th day of the experiment. Extracts stored for 30 days were subjected to polyacrylamide gel electrophoresis, incubated with peroxidase substrates, and the resulting bands were quantified. Three different dependences on storage temperature were noticed. Extracts kept at –196 °C and –20 °C displayed no change in activity, samples kept at +24 °C and +37 °C decreased the activity, while those kept at +4 °C manifested a considerable rise in activity. Electropherogram analysis revealed two isoenzymes, with total activities resembling those obtained spectrophotometrically. There was no difference in isoenzyme appearance between samples. Recommendations regarding enzyme extract storage are given.Peroksidaze su enzimi s brojnim funkcijama u biljnim stanicama. Stoga su ovi enzimi zanimljiv predmet suvremenih biokemijskih istraživanja. Svrha ovoga rada bila je ispitati utjecaj pohranjivanja kroz 30 dana pri različitim temperaturama na aktivnost ukupnih peroksidaza u nepročišćenom ekstraktu iz jednogodišnjih iglica smreke. Aktivnost ukupnih peroksidaza određivana je reakcijom proteinskoga ekstrakta s gvajakolom i H2O2. Količina obojenoga produkta proporcionalna je apsorbanciji na 470 nm. Mjerenja su vršena svaki dan prvih 10 dana, a nakon toga u slijedeće dane pokusa: 12., 14., 16., 18. i 30. Ekstrakti pohranjeni 30 dana bili su podvrgnuti nativnoj elektroforezi na poliakrilamidnome gelu te inkubirani sa supstratima peroksidaza, a intenzitet obojenja vrpci kvantitativno je određen. Uočene su tri različite ovisnosti o temperaturi pohranjivanja. Ekstrakti čuvani na –196 °C i –20 °C nisu promijenili aktivnost, uzorcima čuvanim na +24 °C i +37 °C aktivnost se smanjila, dok se onima čuvanim na +4 °C povećala. Analiza elektroferograma pokazala je postojanje dva izoenzima, pri čemu je zbroj njihovih pojedinačnih aktivnosti za svaku temperaturu pohranjivanja sličan onoj izmjerenoj spektrofotometrijski. Nije bilo razlike u broju i udjelu izoenzima između uzoraka. Preporuča se određ eni način pohranjivanja enzimskoga ekstrakta iz iglica smreke.

Changes in Photosystem II Photochemistry in Senescing Maple Leaves

Biochemical and functional changes in photosystem II (PSII) were investigated during natural senescence of maple (Acer platanoides L.) leaves. Three different types of senescing leaves were used: early senescent green (G), yellow green (YG) and yellow (Y). The main goal of this study was to investigate the dynamics of degradation of major photosynthetic proteins (D1, LHCII and Rubisco LSU) and how this would reflect on PSII photochemistry. It was revealed that D1 and LSU degrade faster than LHCII. Such differential degradation dynamics influenced PSII photochemistry. A decrease in the maximum (Fv/Fm) and effective (ΔF/F\u27m) quantum yields of PSII as well as a decrease in its capability for O2 evolution were observed. Analysis of chlorophyll a fluorescence transient measurement (OJIP test) in senescent leaves showed striking decrease in performance index (PIABS), a measure of overall photosynthetic performance. Further, increased absorption, trapping and dissipation of excitation energy per reaction centre were found in senescent leaves. In addition, it was shown that a marked decrease in electron transport beyond the primary electron acceptor (QA) in Y leaves was due to reduced electron transfer ability from QA– to QB. It can be concluded that molecular and functional modifications of a certain fraction of reaction centres from active to dissipative might be considered an important regulatory mechanism in chloroplast electron-transport chain redox poise control during natural senescence of maple leaves

Photosynthetic Electron Transport and Superoxide Dismutase Activity during Natural Senescence of Maple Leaves

Natural senescence of maple (Acer pseudoplatanus L.) leaves was investigated. Three types of senescing leaves were used: green (G), yellow-green (YG) and yellow (Y) ones. Down regulation of photosynthetic performance was achieved due to significant degradation of total chlorophylls, decrease in maximum quantum yield of PSII (Fv/Fm) and relative electron transport rate (rel. ETR). Also, decrease in Rubisco LSU abundance as well as degradation of rbcL gene was shown in YG and Y leaves. Senescent leaves revealed significant increase in the capacity of PSII for oxygen evolution when expressed per chlorophyll unit. This was the most probable source of reactive oxygen species (ROS) excess. The level of SOD (superoxide dismutase) activity increased 3.5-fold in Y leaves in respect to G and YG leaves. The increase in ROS level as well as in SOD activity during natural senescence of maple leaves was associated with increased level of lipid peroxidation and protein carbonyl content

Simbolika sablje u Yoshikawinom romanu Musashi

In his masterpiece Musashi (1935), the author Eiji Yoshikawa depicts the birth of an ingenious swordsman and his spiritual evolution towards the final awakening (satori). While constructing the character of Miyamoto Musashi, Yoshikawa uses the elements of Zen Buddhist philosophy and describes Musashi\u27s progress on his way of enlightenment through a series of direct personal insights (kensho) that precede satori. The paper aims to discuss and analyze Musashi\u27s use of different types of swords that metaphorically suggest his personal and spiritual transformation from an untamed and uncultivated person to his ultimate enlightenment. Initially, Musashi fights with a wooden sword (bokken), which symbolizes his animalistic, rampant nature. As he progresses on the way of enlightenment, Musashi embraces the steel sword (katana), though he still uses bokken at times. The struggle between his wild and civilized nature culminates at the moment of kensho, when he starts fighting with two steel swords, which represents a true evolution that elevates him to the level of the Nietzschean Übermensch. The final birth of Musashi as a Rinzaian “man of no rank” is the moment of his ultimate awakening, symbolically depicted when he again reaches for the wooden sword. This act unmasks his true Buddhist nature, thus suggesting Musashi\u27s return to “oneself.

Changes in Photosystem II Photochemistry in Senescing Maple Leaves

Biochemical and functional changes in photosystem II (PSII) were investigated during natural senescence of maple (Acer platanoides L.) leaves. Three different types of senescing leaves were used: early senescent green (G), yellow green (YG) and yellow (Y). The main goal of this study was to investigate the dynamics of degradation of major photosynthetic proteins (D1, LHCII and Rubisco LSU) and how this would reflect on PSII photochemistry. It was revealed that D1 and LSU degrade faster than LHCII. Such differential degradation dynamics influenced PSII photochemistry. A decrease in the maximum (Fv/Fm) and effective (ΔF/F\u27m) quantum yields of PSII as well as a decrease in its capability for O2 evolution were observed. Analysis of chlorophyll a fluorescence transient measurement (OJIP test) in senescent leaves showed striking decrease in performance index (PIABS), a measure of overall photosynthetic performance. Further, increased absorption, trapping and dissipation of excitation energy per reaction centre were found in senescent leaves. In addition, it was shown that a marked decrease in electron transport beyond the primary electron acceptor (QA) in Y leaves was due to reduced electron transfer ability from QA– to QB. It can be concluded that molecular and functional modifications of a certain fraction of reaction centres from active to dissipative might be considered an important regulatory mechanism in chloroplast electron-transport chain redox poise control during natural senescence of maple leaves