Seasonal changes in the pigment composition of needles of representatives of the genus spruce in the Nizhny Novgorod region

Изучали таксационные показатели лесных культур лиственницы Сукачева, заложенных в 1986 г. на юго-западной границе естественного распространения вида в Сергачском межрайонном лесничестве Нижегородской области. Координаты первого участка N 55.541378, E 45.471119; второго – N 55.541388, E 45.471125. Получена оценка эффективности их создания в указанном регионе. Методологической основой рабочих методик служил принцип единственного логического различия. Работа выполнялась полевым стационарным методом. Характеристика культур лиственницы давалась по результатам натурного обследования. Пробные площади закладывали в соответствии с действующим отраслевым стандартом. Подтверждена благоприятность лесорастительных условиях для естественного произрастания лиственницы Сукачева и широкие возможности интродукции близкородственных видов. Обнаружена неодинаковая изменчивость таксационных показателей. В частности, по диаметру ствола и его высоте она незначительна и отнесена преимущественно к низкому уровню: на первом участке 14,21% и 11,34%; на втором – 17,11 и 9,16% соответственно. По другим признакам изменчивость выше (чаще средний и повышенный уровень) и в ряде случаев достигает высокого (объем ствола) и очень высокого (коэффициент асимметрии кроны) уровня. Зафиксированы существенные различия между участками лесных культур по большинству таксационных показателей, подтвержденные дисперсионным анализом. Эффект их влияния на общий фон фенотипической дисперсии неодинаков. По диаметру ствола он минимален и составил 6,68±1,37%. Наибольшие оценки получены по расстоянию до первого живого сучка – 30,42±1,05%. Определено, что лесные культуры лиственницы Сукачева, созданные в Нижегородской области, достигая к возрасту 34 высоты 14 – 15 м, формируют насаждения первого класса бонитета. We studied the taxation indicators of forest crops of Sukhdev larch, laid in 1986 on the south-western border of the natural distribution of the species in the Sergachsky interdistrict forestry of the Nizhny Novgorod region. The coordinates of the first section are N 55.541378, E 45.471119; the second section is N 55.541388, E 45.471125. An assessment of the effectiveness of their creation in the specified region was obtained. The methodological basis of the working methods was the principle of the only logical difference. The work was carried out by the field stationary method. The characteristics of larch crops were given based on the results of a field survey. The test areas were laid in accordance with the current industry standard. The favorable forest conditions for the natural growth of Sukachev larch and the wide opportunities for the introduction of closely related species were confirmed. Unequal variability of taxation indicators was found. In particular, in terms of trunk diameter and height, it is insignificant and is mainly attributed to the low level: in the first section, 14.21% and 11.34%; in the second-17.11 and 9.16%, respectively. According to other signs, the variability is higher (more often the average and increased level) and in some cases reaches a high (trunk volume) and very high (crown asymmetry coefficient) level. Significant differences between forest crop plots were recorded in most of the taxation indicators, which were confirmed by the analysis of variance. The effect of their influence on the general background of the phenotypic variance is not the same. By the diameter of the trunk, it is minimal and amounted to 6.68±1.37%. The highest estimates were obtained for the distance to the first live knot – 30.42±1.05%. It is determined that the forest cultures of Sukachev larch, created in the Nizhny Novgorod region, reaching a height of 14-15 m by the age of 34, form plantings of the first class of bonitet.

Population structure of geographical cultures of European spruce in the estimates of the pigment composition of needles

Изучали содержание и соотношение пластидных пигментов в хвое представителей разных популяций ели европейской, введенных в состав географических культур на территории Нижегородской области. Применяли спектрофотометрический метод выявления количественных оценок пигментного состава листового аппарата с обеспечением принципа единственного логического различия и основных требований к организации опыта. Проведены натурные обследования насаждений и лабораторные анализы биологических проб. Выявлены различия между представителями удаленных друг от друга популяций ели европейской при их совместном выращивании в составе географических культур по комплексу показателей пигментного состава однолетней хвои. Наибольшее содержание хлорофилла-а (3,25±0,06 мг/г) отмечено у семенного потомства популяций из Псковской области, что в 1,26 раза превосходит соответствующий минимум (2,57±0,04 мг/г), зафиксированный у представителей популяций из Калининградской области. Зафиксированы сходные масштабы соотношения оценок содержания хлорофилла-b, притом что максимальные значения (1,37±0,05 мг/г и 1,37±0,06 мг/г) наблюдались у происхождений из Костромской и Карельской областей, а минимальные (1,07±0,03 мг/г и 1,09±0,03 мг/г) – у представителей популяций из Архангельской и Калининградской областей. Подтверждена существенность различий между популяциями ели европейской по всем рассматриваемым показателям пигментного состава. Обнаружено сходство в сложении трех группировок популяций, возникших при выполнении факторного и кластерного анализа. Коэффициенты плотности кластера (средняя евклидова дистанция его сложения) каждой их них составили: 6,258 единиц евклидовой дистанции (у первой); 4,374 ед. (у второй); 7,818 ед. (у третьей) и 6,150 ед. (общая средняя дистанция). Среднее межкластерное расстояние при этом достигло 20,414 ед., что принципиально больше величин внутрикластерных дистанций и позволяет признать корректным выделение кластеров. Обоснован устойчивый характер соотношения популяций ели европейской, имеющих различное географическое происхождение, по пигментному составу хвои. The content and ratio of plastid pigments in the conifers of representatives of different populations of Norway spruce introduced into the geographic test-cultures in the Nizhny Novgorod region were studied. A spectrophotometric method was used to identify quantitative estimates of the pigment composition of the leaf apparatus, ensuring the principle of a single logical difference and the basic requirements for the organization of the experiment. Field surveys of plantings and laboratory analyses of biological samples were carried out. The differences between representatives of Norway spruce populations that are remote from each other were revealed when they were grown together as part of geographical crops according to the complex of indicators of the pigment composition of annual needles. The highest content of chlorophyll-a (3.25±0.06 mg/g) was observed in the seed offspring of populations from the Pskov region, which is 1.26 times higher than the corresponding minimum (2.57±0.04 mg/g) recorded in representatives of populations from the Kaliningrad region. Similar scales of the ratio of estimates of the content of chlorophyll-b were recorded, despite the fact that the maximum values (1.37±0.05 mg/g and 1.37±0.06 mg/g) were observed in the origin from the Kostroma and Karelian regions, and the minimum values (1.07±0.03 mg/g and 1.09±0.03 mg/g) were observed in representatives of populations from the Arkhangelsk and Kaliningrad regions. The significance of differences between the populations of Norway spruce in all the considered indicators of pigment composition was confirmed. A similarity was found in the addition of three groups of populations that arose during factor and cluster analysis. The cluster density coefficients (the average Euclidean distance of its addition) of each of them were: 6,258 units of the Euclidean distance (for the first one); 4,374 units. (in the second); 7,818 units. (at the third) and 6,150 units. (total average distance). The average inter-cluster distance at the same time reached 20,414 units, which is fundamentally greater than the values of intra-cluster distances and allows us to recognize the correct allocation of clusters. The stable nature of the ratio of populations of Norway spruce with different geographical origin, according to the pigment composition of needles, is justified.

Retrieval of Phytoplankton Pigment Composition from Their In Vivo Absorption Spectra

Algal pigment composition is an indicator of phytoplankton community structure that can be estimated from optical observations. Assessing the potential capability to retrieve different types of pigments from phytoplankton absorption is critical for further applications. This study investigated the performance of three models and the utility of hyperspectral in vivo phytoplankton absorption spectra for retrieving pigment composition using a large database (n = 1392). Models based on chlorophyll-a (Chl-a model), Gaussian decomposition (Gaussian model), and partial least squares (PLS) regression (PLS model) were compared. Both the Gaussian model and the PLS model were applied to hyperspectral phytoplankton absorption data. Statistical analysis revealed the advantages and limitations of each model. The Chl-a model performed well for chlorophyll-c (Chl-c), diadinoxanthin, fucoxanthin, photosynthetic carotenoids (PSC), and photoprotective carotenoids (PPC), with a median absolute percent difference for cross-validation (MAPDCV) < 58%. The Gaussian model yielded good results for predicting Chl-a, Chl-c, PSC, and PPC (MAPDCV < 43%). The performance of the PLS model was comparable to that of the Chl-a model, and it exhibited improved retrievals of chlorophyll-b, alloxanthin, peridinin, and zeaxanthin. Additional work undertaken with the PLS model revealed the prospects of hyperspectral-resolution data and spectral derivative analyses for retrieving marker pigment concentrations. This study demonstrated the applicability of in situ hyperspectral phytoplankton absorption data for retrieving pigment composition and provided useful insights regarding the development of bio-optical algorithms from hyperspectral and satellite-based ocean-colour observations.

Curvature thylakoid 1 proteins modulate prolamellar body morphology and promote organized thylakoid biogenesis in Arabidopsis thaliana

The term “de-etiolation” refers to the light-dependent differentiation of etioplasts to chloroplasts in angiosperms. The underlying process involves reorganization of prolamellar bodies (PLBs) and prothylakoids into thylakoids, with concurrent changes in protein, lipid, and pigment composition, which together lead to the assembly of active photosynthetic complexes. Despite the highly conserved structure of PLBs among land plants, the processes that mediate PLB maintenance and their disassembly during de-etiolation are poorly understood. Among chloroplast thylakoid membrane–localized proteins, to date, only Curvature thylakoid 1 (CURT1) proteins were shown to exhibit intrinsic membrane-bending capacity. Here, we show that CURT1 proteins, which play a critical role in grana margin architecture and thylakoid plasticity, also participate in de-etiolation and modulate PLB geometry and density. Lack of CURT1 proteins severely perturbs PLB organization and vesicle fusion, leading to reduced accumulation of the light-dependent enzyme protochlorophyllide oxidoreductase (LPOR) and a delay in the onset of photosynthesis. In contrast, overexpression of CURT1A induces excessive bending of PLB membranes, which upon illumination show retarded disassembly and concomitant overaccumulation of LPOR, though without affecting greening or the establishment of photosynthesis. We conclude that CURT1 proteins contribute to the maintenance of the paracrystalline PLB morphology and are necessary for efficient and organized thylakoid membrane maturation during de-etiolation.

Hereditary dependence of pigment composition in genus larch needles

The content and ratio of plastid pigments in the conifers of three species of the larch genus (Larix Mill.) were studied: Siberian larch (L. sibirica Ledeb.), Gmelin’s larch (L. Gmelinii (Rupr.) Rupr.), Sukachev’s larch (L. Sukaczewii Dylis). Their seed progeny is concentrated on a pilot site in the Sergachsky forestry of the Nizhny Novgorod region with geographical coordinates 55°32 ‘14,2” N 45°28’01,0” E and an absolute height of 160 m. The site is assigned to the zone of coniferous-broad-leaved forests (the third forest-growing zone) and is included in the area of coniferous-broad-leaved (mixed) forests of the European part of the Russian Federation. The content of chlorophyll a, chlorophyll b and carotenoids in the needles was determined by spectrophotometric method at wavelengths: 665 nm, 649 nm, 452,5 nm. Samples for research were prepared in accordance with the principle of a single logical difference and randomized sample formation. Phenotypic differences in the pigment composition of needles between representatives of these species were revealed. The pigment composition of Siberian larch is dominated by chlorophyll a (3,76 ± 0,12 mg/g), significantly less chlorophyll b (1,87 ± 0,07 mg/g) and even less carotenoids (0,59 ± 0,02 mg/g). The same is observed in the pigment composition of other larch species. The hereditary conditionality of the species specificity of Siberian larch, Gmelin’s larch and Sukachev’s larch was established for all the tested characteristics. The greatest influence (29,84 ± 1,61 %) on the formation of the total phenotypic dispersion was observed in the ratio of the content of chlorophyll-a to the content of carotenoids, the least (5,89 ± 2,16 %) — in the content of dry matter in the needles. Relatively high values were obtained for the proportion of carotenoids (26,74 ± 1,68 %) and the ratio of their content to the total of chlorophylls (26,39 ± 1,69 %). The studied species showed an unequal level of similarity or significant differences in the individual characteristics of the pigment composition of needles.

PsbS Dependence in Lipid and Pigment Composition in Rice Plants

Plants acclimate to fluctuations in light conditions by adjusting their photosynthetic apparatus. When the light intensity exceeds, an unbalanced excitation of the two photosystems occurs. It results in reduced photosynthetic efficiency. Photosystem II (PSII) is the most susceptible and dynamically regulated part of the light reactions in the thylakoid membrane. Non-photochemical quenching of chlorophyll fluorescence (NPQ) is one of the short-term photoprotective mechanisms, which consist of the number of components. The strongest NPQ component — qE is localized in the PSII antenna and induced in plants by lumen acidification, the activation of the pH sensor PsbS, and the conversion of the violaxanthin to zeaxanthin within the xanthophyll cycle. Here, I present data that characterizes the role of the PsbS protein in organization of PSII structural components in isolated PSII-enriched membranes. The preparations were isolated from wild-type (WT) and PsbS-less (PsbS-KO) mutant rice plant. Based on the obtained results, the PSII-enriched membranes from WT and PsbS-KO differ as in the level of lipids, also in carotenoids. I conclude that the PsbS-dependent changes in membrane fluidity in PsbS-KO mutant plants compensated with increased lipid level in mutant plants.