Carrot plastid terminal oxidase gene ( DcPTOX ) responds early to chilling and harbors intronic pre-miRNAs related to plant disease defense

Photosynthetic Pigments Content in Emmer Wheat Plants as Criteria of Productivity in Traditional and Organic Farming Technology

Background. Estimation of chlorophyll and carotenoid content is an informative way to obtain ideas about the plants photosynthetic process and is an indirect method for assessing the productivity of plant crops, including cereals. As the worldwide interest at now for traditional and natural foods is growing, in the work we used one of the oldest grain crops – emmer wheat (Triticum dicoccum (Schrank.) Schuebl.) which was cultivated in traditional and organic farming system. Objective. The study aim was to determine the role of chlorophyll and carotenoids in the emmer wheat productivity formation by traditional and organic farming technology under different pre-sowing seed treatment systems. Methods. Field experiment was establishment during 2019–2021 on low-humus, hard-loam chernozems, the condition of which meets the “virgin land” criterion. The emmer wheat cultivation in organic technology was carried out in crop rotation: winter rye (green manure crop) – mustard (to improve the field phytosanitary condition and soil organic matter indicators) – emmer wheat. Two variants of pre-sowing seed treatment were studied: irradiation with ultraviolet light of the C range (100–280 nm) and seed treatment with 1r Seed Treatment humic preparation. The pre-sowing seed treatment in the traditional technology of the emmer wheat cultivation was carried out by the UV-C irradiation. In organic technology both UV-C irradiation and treatment with 1r Seed Treatment humic preparation of natural origin were used. Statistical data processing was performed by methods of descriptive statistics, regression and analysis of variance by the program Statistica 10.0. The experimental data significance was evaluated by using multifactor analysis of variance (ANOVA) to calculate the least significant difference (LSD05). Results. It was found the use of UV-C seeds irradiation in organic and traditional cultivation technologies leads to increase in the chlorophyll a (Chl a) content by 9.2 % and chlorophyll b (Chl b) content by 14.5 % in plants grown by organic technology, however to decrease in carotenoid content (Ct) by 14.9 %. The increase in the photosynthetic pigments content by UV-C seeds irradiation lead to yield increase from 4.26 t/ha by the traditional technology to 5.17 t/ha by the organic technology, ie by 21.4 %. In organic technology based on the comparison of the photosynthetic apparatus main indicators of the emmer wheat and yield, the most effective method for seed treatment was determined. It was established that at result of 1r Seed Treatment humic preparation application in pre-sowing seed treatment, the Chl a concentration decreased by 2.4 %, the Chl b and Ct concentration increased by 5 and 25.5 %, respectively, compared with plants grown from UV-C irradiated seeds. When 1r Seed Treatment was used for pre-sowing treatment yield was 5.58 t/ha, while at UV-C seed treatment – 5.17 t/ha, ie, the yield increase was 8 %. An inverse correlation between the ratio of the photosynthetic pigments Chl a/Chl b content and the emmer wheat yield was determined. Conclusions. According to the study results, it can be assumed that the introduction of organic farming technology with pre-sowing seed treatment by the 1r Seed Treatment humic preparation can increase the emmer wheat yield by 31% compared to the traditional technology. Thus, the photosynthetic pigments content and their ratio can be the effectiveness indicators of the implemented agricultural technologies.

The Morpho-Physio-Biochemical Attributes of Urban Trees for Resilience in Regional Ecosystems in Cities: A Mini-Review

Increased urbanization means human beings become the dominant species and reduction in canopy cover. Globally, urban trees grow under challenging and complex circumstances with urbanization trends of increasing anthropogenic carbon dioxide (CO2) emissions, high temperature and drought stress. This study aims to provide a better understanding of urban trees’ morpho-physio-biochemical attributes that can support sustainable urban greening programs and urban climate change mitigation policies. Globally, urban dwellers’ population is on the rise and spreading to suburban areas over time with an increase in domestic CO2 emissions. Uncertainty and less information on urban tree diversification and resistance to abiotic stress may create deterioration of ecosystem resilience over time. This review uses general parameters for urban tree physiology studies and employs three approaches for evaluating ecosystem resilience based on urban stress resistance in relation to trees’ morphological, physiological and biochemical attributes. Due to the lack of a research model of ecosystem resilience and urban stress resistance of trees, this review demonstrates that the model concept supports future urban tree physiology research needs. In particular, it is necessary to develop integral methodologies and an urban tree research concept to assess how main and combined effects of drought and/or climate changes affect indigenous and exotic trees that are commonly grown in cities.

Effect of Long-Term of He-Ne Laser Light Irradiation on Selected Physiological Processes of Triticale

In agriculture, the bio-stimulating properties of laser light increase the yielding capacity of crop species. The experiment aimed to determine the pre-sowing effect of irradiation time with laser He-Ne red light of triticale grains (×Triticosecale Wittm. ex A.Camus) on germination and selected morphological and physiological parameters of seedlings and plants grown from them. The highest values of germination indexes were found for grains irradiated with laser for 3 h. In relation to the control, the elongation growth of seedlings was stimulated in grains irradiated with light for 3 h and inhibited for 24 h. The values of the fresh and dry mass of seedlings changed depending on the exposure time. He-Ne light did not significantly affect the degree of destabilization of seedling cell membranes. Biometric analysis of plants grown from irradiated grains showed different reactions of triticale organs to the irradiation time. Red light clearly stimulated the increase in the value of organ mass. Chlorophyll content in leaves was higher in plants grown from grains irradiated for 3 h. Photosynthetic activity did not change significantly relative to the control. The fluorescence emission indexes were mostly lower than in the control, which indicated a positive effect of the laser. In general, the red light of the laser stimulated the morphology and physiology of seedlings and plants, although, for some features, long exposure to red light caused a slight reduction effect.

Ecophysiological Analysis of Mangrove Seedlings Kandelia obovata Exposed to Natural Low Temperature at Near 30°N

In this study, mangrove seedlings Kandelia obovata were firstly introduced to Zhoushan in Eastern China at 29° 93′ N from Xuwen in South China at 20° 34′ N in April 2016. In order to analyze ecophysiological differences of K. obovata seedlings domesticated in Zhoushan, the growth status and antioxidant system of K. obovata exposed to natural low temperature were studied through situ measurements. The results showed that K. obovata seedlings introduced artificially to Zhoushan grew slowly when subjected to natural cold stress. The chlorophyll contents exhibited a decreased tendency. In addition, 2-butanol and 2,3-butanediol were firstly found in K. obovata after being moved to Zhoushan, which are specific substances produced by K. obovata under low-temperature stress. Moreover, there was a synergistic competition mechanism in the antioxidant enzyme system in K. obovata, in which superoxide dismutase (SOD) would convert oxygen radicals to hydrogen peroxide, and then catalase (CAT) and peroxidase (POD) could work together to remove hydrogen peroxide. This study provides a foundation for better understanding of the response of mangroves to natural low temperature at high latitudes.

Tissue specific disruption of photosynthetic electron transport rate in pigeonpea (Cajanus cajan L.) under elevated temperature

Nutritional rich pigeonpea (Cajanus cajan [L.]), a perennial shrub member of family Fabaceae is the sixth most important grain legume of the world. Continuous rise of temperature and current global climate scenario limits plant growth and performance but photosynthetic machineries are adversely affected. The aim of this study was the analysis of tissue specific photosynthetic pigments and photosynthetic electron transport rate under elevated temperature. Two different stages of both leaf (young and mature), and pod (young and mature) were chosen, and photosynthetic pigment and J-I-P tests were measured. Leaves and pods were detached and incubated in normal temperature (25°C) for 24 h in two different condition one light irradiance (100 µmol m^-2 s^-1) and another darkness as control, and treated with high temperature 45°C for 24 h and repeated previous measurements were taken. Tissue specific photosynthetic pigments variation were observed; J-I-P parameters clearly revealed that elevated temperature has greater influence on photosystem II (PSII) electron transport than photosystem I (PSI), and significant changes were observed in pods than leaves. Young tissues were adversely affected by elevated temperature. In addition, the J-I-P tests and energy pipeline model indicated that PSI electron transport rate of leaves and pods appeared to be more thermo-tolerance than those in PSII. Only a minor drop in pigments pool and photosynthetic performance was observed after 24 h of darkness. O-J-I-P transients can be used as a sensitive, nondestructive method for measuring heat stress damage and a special tool for investigating action sites of high temperature stress. Findings of this study will contribute to basic understanding of photosynthetic performance, and to screen potential thermo-tolerant genotypes of pigeonpea to sustain in either current scenario of climate change or/and erratic future climatic conditions.

Response of Chlorophyll, Carotenoid and SPAD-502 Measurement to Salinity and Nutrient Stress in Wheat (Triticum aestivum L.)

Abiotic stress can alter key physiological constituents and functions in green plants. Improving the capacity to monitor this response in a non-destructive manner is of considerable interest, as it would offer a direct means of initiating timely corrective action. Given the vital role that plant pigments play in the photosynthetic process and general plant physiological condition, their accurate estimation would provide a means to monitor plant health and indirectly determine stress response. The aim of this work is to evaluate the response of leaf chlorophyll and carotenoid (Ct) content in wheat (Triticum aestivum L.) to changes in varying application levels of soil salinity and fertilizer applied over a complete growth cycle. The study also seeks to establish and analyze relationships between measurements from a SPAD-502 instrument and the leaf pigments, as extracted at the anthesis stage. A greenhouse pot experiment was conducted in triplicate by employing distinct treatments of both soil salinity and fertilizer dose at three levels. Results showed that higher doses of fertilizer increased the content of leaf pigments across all levels of soil salinity. Likewise, increasing the level of soil salinity significantly increased the chlorophyll and Ct content per leaf area at all levels of applied fertilizer. However, as an adaptation process and defense mechanism under salinity stress, leaves were found to be thicker and narrower. Thus, on a per-plant basis, increasing salinity significantly reduced the chlorophyll (Chlt) and Ct produced under each fertilizer treatment. In addition, interaction effects of soil salinity and fertilizer application on the photosynthetic pigment content were found to be significant, as the higher amounts of fertilizer augmented the detrimental effects of salinity. A strong positive (R2 = 0.93) and statistically significant (p < 0.001) relationship between SPAD-502 values and Chlt and between SPAD-502 values and Ct content (R2 = 0.85) was determined based on a large (n = 277) dataset. We demonstrate that the SPAD-502 readings and plant photosynthetic pigment content per-leaf area are profoundly affected by salinity and nutrient stress, but that the general form of their relationship remains largely unaffected by the stress. As such, a generalized regression model can be used for Chlt and Ct estimation, even across a range of salinity and fertilizer gradients.