High Plant Productivity Research Articles

Effects of temporal heterogeneity in nutrient supply on intra- and inter-genet competition of a clonal herb

Nutrients are often released heterogeneously over time (e.g., in pulses) in natural habitats. Different genotypes of the same plant species may vary in their responses to temporal nutrient heterogeneity so that temporal nutrient heterogeneity may influence intraspecific interactions. To test effects of temporal nutrient heterogeneity on intra-genet (competition between ramets of the same genotype) and inter-genet competition (competition between ramets of different genotypes), we conducted a greenhouse experiment with five genotypes of the clonal herb Hydrocotyle vulgaris. We grew one ramet (no competition), two ramets of the same genotype or two ramets of different genotypes in a pot and supplied the pot with the same total amount of nutrients either homogeneously or heterogeneously. Results showed that temporal nutrient heterogeneity affected the growth and biomass allocation of some genotypes, but had no impact on those of other genotypes of H. vulgaris. These suggested that responses to temporal nutrient heterogeneity were different between genotypes of H. vulgaris. Temporal nutrient heterogeneity had little effect on intra-genet competition of H. vulgaris likely because ramets of the same genotype did not differ in their responses to temporal nutrient heterogeneity. However, temporal nutrient heterogeneity increased the competitive ability of the genotype of H. vulgaris with higher plant productivity. We conclude that temporal nutrient heterogeneity can influence intraspecific interactions of the clonal plant H. vulgaris by altering inter-genet competition, and this effect may further change population dynamics of the plant.

The shifting mosaic of ice-wedge degradation and stabilization in response to infrastructure and climate change, Prudhoe Bay Oilfield, Alaska, USA

We studied processes of ice-wedge degradation and stabilization at three sites adjacent to road infrastructure in the Prudhoe Bay Oilfield, Alaska, USA. We examined climatic, environmental, and subsurface conditions and evaluated vulnerability of ice wedges to thermokarst in undisturbed and road-affected areas. Vulnerability of ice wedges strongly depends on the structure and thickness of soil layers above ice wedges, including the active, transient, and intermediate layers. In comparison with the undisturbed area, sites adjacent to the roads had smaller average thicknesses of the protective intermediate layer (4 cm vs. 9 cm), and this layer was absent above almost 60% of ice wedges (vs. ∼45% in undisturbed areas). Despite the strong influence of infrastructure, ice-wedge degradation is a reversible process. Deepening of troughs during ice-wedge degradation leads to a substantial increase in mean annual ground temperatures but not in thaw depths. Thus, stabilization of ice wedges in the areas of cold continuous permafrost can occur despite accumulation of snow and water in the troughs. Although thermokarst is usually more severe in flooded areas, higher plant productivity, more litter, and mineral material (including road dust) accumulating in the troughs contribute to formation of the intermediate layer, which protects ice wedges from further melting.

Seagrass meadows mixed with calcareous algae have higher plant productivity and sedimentary blue carbon storage.

Seagrass meadows capture and store large amounts of carbon in the sediment beneath, thereby serving as efficient sinks of atmospheric CO2. Carbon sequestration levels may however differ greatly among meadows depending on, among other factors, the plant community composition. Tropical seagrass meadows are often intermixed with macroalgae, many of which are calcareous, which may compete with seagrass for nutrients, light, and space. While the photosynthetic CO2 uptake by both seagrasses and calcareous algae may increase the overall calcification in the system (by increasing the calcium carbonate saturation state, Ω), the calcification process of calcareous algae may lead to a release of CO2, thereby affecting both productivity and calcification, and eventually also the meadows’ carbon storage. This study estimated how plant productivity, CaCO3 production, and sediment carbon levels were affected by plant community composition (seagrass and calcareous algae) in a tropical seagrass‐dominated embayment (Zanzibar, Tanzania). Overall, the patterns of variability in productivity differed between the plant types, with net areal biomass productivity being highest in meadows containing both seagrass and calcareous algae. Low and moderate densities of calcareous algae enhanced seagrass biomass growth, while the presence of seagrass reduced the productivity of calcareous algae but increased their CaCO3 content. Sedimentary carbon levels were highest when seagrasses were mixed with low or moderate cover of calcareous algae. The findings show that plant community composition can be an important driver for ecosystem productivity and blue carbon sequestration.

Plant density and manure application affected yield and essential oil composition of Bakhtiari savory (Satureja bachtiarica Bunge.)

The use of soil amendments and cultivated techniques are effective strategies in improving plant yield. Bakhtiari savory (Satureja bachtiarica Bunge.) is an endemic medicinal plant of Iran with various medicinal purposes. To observe the effect of cattle manure (30 t ha−1) and plant density (high plant density, HPD: 80,000; medium plant density, MPD: 40,000, and low plant density, LPD: 26,666 plants ha−1), an experiment was accomplished as split plot with three replicates during 2018 and 2019 on plant yield, nutrients concentration, essential oil (EO) yield and composition, and also stomatal properties of Bakhtiari savory in the dryland farming conditions. The maximum plant weight was observed with manure application at HPD plant density in the second year. The greatest concentrations of N, Ca, and Mg were obtained in the plans treated with manure application and HPD. The increase of plant density led to decreased EO content and increased EO yield. The highest EO yield was observed in second-year plants supplied with manure at HPD. The GC and GC/MS analysis showed that the main constitutes of Bakhtiari savory EO were p-cymene (18.6–43%), carvacrol (32.3–59.3%), γ-terpinene (5–14.3%), thymol (0.6–17.8%), and linalool (2–4.3%), representing different concentrations under the manure and plant densities. Leaf stomatal density and length at LPD was lower compared with HPD and MPD, while increased density of EO glands was obtained at LPD. To sum up, cattle manure and HPD can result in higher plant production.

ВПЛИВ СИСТЕМ ОБРОБІТКУ ГРУНТУ ТА УДОБРЕННЯ ІЗ ВИКОРИСТАННЯМ ПОБІЧНОЇ ПРОДУКЦІЇ НА ПРОДУКТИВНІСТЬ ПШЕНИЦІ ОЗИМОЇ В ЗАХІДНОМУ ПОЛІССІ УКРАЇНИ

The peculiarities of influence of tillage and fertilization systems with use of by-products on the winter wheat productivity were established by research, which was conducted on dark gray podzolic soil the in a four-field short-term crop rotation (winter rape - winter wheat – maize – spring barley). We studied three tillage systems (nonmoldboard plowing to 20–22 cm, shallow tillage to 10–12 cm, and surface tillage to 6–8 cm) and fertilization system with the use of crop by-products on the background of mineral fertilizers N128P90K120 kg/ha of crop rotation area. The highest plant productivity was formed by moldboard plowing to 20–22 cm and shallow tillage to 10–12 cm in fertilization variants with straw and straw + Ecostern destructor, in this case, the thousand grain weight was 47.1 and 47.9 and 46.4 and 47.0 g, the of grain weight per spike – 2.1 and 2.2 and 1.9 and 2.0 g. And lowest plant productivity was under surface tillage to 6–8 cm and various fertilization systems, where the thousand grain weight was 45.2–45.6 g, and the grain weight per spike 1.8–1.9 g. At moldboard and non-moldboard plowing to 10–12 cm and using straw + destructor, it was observed that an gluten content in winter wheat grain increased to 23.5 and 22.7 %, and protein content – to 12.9–11.7 % compared to with surface tillage, where these figures were 21.5 and 9.5 %, respectively. It was found that the moldboard plowing to 20–22 cm and shallow tillage to 10–12 cm was effective at winter wheat cultivation, which formed a higher grain yield – 6.80 and 6.32 t/ha. It was clarified that surface tillage to 6–8 cm caused a decrease in grain yield by 1.45 t/ha compared to the moldboard plowing. On average, over the research years, there was an increase in yield by 0.36 and 0.45 t/ha due to the use of straw as a fertilizer separately and in combination with the Ecostern destructor. By comparison, in the variant without straw, the yield was 5.89 t/ha on average by a factor. Consequently, we established that for winter wheat cultivation in the Western Polissia of Ukraine, it is expedient to carry out the moldboard plowing to 20–22 cm and the non-moldboard plowing to 10–12 cm and to use fertilization system with straw + Ecostern destructor + N 10 kg (ammonium nitrate) per 1 ton of straw. Key words: winter wheat, tillage, fertilizers, yield, destructor.

Fuzzy logic based prediction of micronutrients demand for harumanis mango growth cycles

Harumanis is a famous green eating mango cultivar that has been commercially cultivated in Malaysia’s state of Perlis. A variety of nutrients are found in soil, all of which are necessary for plant growth. Micronutrients such as Nitrogen (N), Phosphorus (P), and Potassium (K) are essential for Harumanis mango (Mangifera Indica) to growth. The importance of soil fertility in achieving high plant productivity and quality cannot be overstated. It should be used in a moderate amount and in a balanced manner. Predicting appropriate nutrients and the right timing to satisfy the tree’s demands is critical. The aim of this study is to create for Harumanis mango a fuzzy logic-based system to analyse the results of soil tests for nitrogen (N), phosphorus (P), and potassium (K) in the Harumanis mango orchard. The interpreted data are used to estimate N-P-K nutrient levels and indicate the optimal fertilizer solution and application timing for each Harumanis growth stages. The system utilizes Fuzzy Logic Control (FLC) to predict the nutrients demand for Harumanis mango growth. Results shows the system able to calculate and predict values of required N-P-K fertilizer for optimal growth. Thus, assist farmers in predicting the proper amount of N-P-K to apply to Harumanis mango soil.

Integrating maintenance strategies in autonomous production control using a cost-based model

<p class="Abstract">Autonomous production control (APC) is able to deal with challenges, inter alia, high delivery accuracy, shorter planning horizons, increasing product and process complexity, and frequent changes. However, several state-of-the-art approaches do not consider maintenance factors contributing to operational and tactical decisions in production planning and control. The incomprehensiveness of the decision models and related decision support tools cause inefficiency in production planning and thus lead to a low acceptance in the manufacturing enterprises. To overcome this challenge, this paper presents a conceptual cost-based model for integrating different maintenance strategies in autonomous production control. The model provides relevant decision aspects and a cost function for different maintenance strategies using on a market-based approach. The present work thus makes a positive contribution to cope with the high demands on flexibility and response times in planning while at the same time ensuring high plant productivity.</p>

Carbon Storage on Different Species of Seagrass on Tourist Destination Areas: A Measure of Disturbed and Undisturbed Environments

Carbon absorption and storage, known as carbon sequestration, have reduced global warming through photosynthesis. Seagrass beds in coastal ecosystems have high plant productivity and are found to have the ability to reduce the effect of global warming due to the increase of CO2 in the atmosphere. Due to the anthropogenic effect, decreasing environmental quality, such as tourism, may affect seagrass diversity and growth, therefore its carbon contents. This study investigates the ability of seagrass species as carbon storage and their diversity in a common tourist destination area referred to as disturbed habitat, located at Sanur and an area that is less disturbed, referred to as undisturbed habitat. Samples were collected from 3 transects 50m in length that were placed on each site. Three plots, each measuring 0.5 x 0.5 m, were employed on each transect. The number of individuals of each species and the percent plant coverage were measured on each plot. Plant biomass and carbon content were extracted in the Lab and divided into below- and above-ground. The result shows that eight species were found at Sanur and only four from Samuh sites. On average, the percentage of plant coverage was higher at the Samuh site. Samuh site. The plant biomass and carbon storage were lower at Samuh than at the Sanur site. Species differences from each site affect the plant biomass, so the carbon content. Anthropogenic activities are not the only ones to determine the carbon storage of seagrass, but rather the species morphology.

Residual Effect of Cow Dung Fertilizer to Corn (Zea mays L.) Growth and Yield in Planting Period II in Marginal Land

Aims: The research aimed to study the potential of cow dung fertilizer residue in increasing the growth and yield of corn plant in planting period II on marginal dry land.
 Study Design: Singel factor design in Randomized block design.
 Place and Duration of Study: The research was conducted in Field Laboratory of the Faculty of Animal Husbandry, University of Halu Oleo, Kendari, Southeast Sulawesi, Indonesia. The study was conducted for four months.
 Methodology: Single factor design in Randomized block design was used in the research. consists of 6 treatment levels of cow manure residue that have been applied in the previous planting period (planting period I), namely: without cow manure (R0), using cow manure 2.5 t ha-1 (R1), 5 t ha-1 (R2), 7.5 t ha-1 (R3), 10 t ha-1 (R4) and 12.5 t ha-1 (R5). Each treatment was placed in three groups so that there were 18 experimental units. The data was analyzed using analysis of variance and continued by Duncan’s Multiple Range Test (DMRT) 95% confidence level.
 Results: The results showed that the vegetative growth of corn plant 30 day after planting (dap) and plant yield was affected by residual effect of cow dung that applicated in the planting periode I, thus with P uptake by plant and available P in planting medium. 
 Conclusion: Plant productivity during planting period II more increased with the higher dose of cow manure applied during planting period I. The highest plant productivity (3.88 t ha-1) in planting period II was obtained by application of cow dung 12.5 t ha-1 during planting period I. While in the planting medium without cow dung, no seeds formation was found in plants.

Impacts of oxalic acid-activated phosphate rock and root-induced changes on Pb bioavailability in the rhizosphere and its distribution in mung bean plant.

Rhizosphere acidification in leguminous plants can release P from the dissolution of phosphate compounds which can reduce Pb bioavailability to them via the formation of insoluble Pb compounds in their rhizosphere. A soil polluted from Pb-acid batteries effluent (SPBE), having total Pb=639mgkg-1, was amended with six different rates (0, 0.5, 1, 2, 4 and 6%) of oxalic acid-activated phosphate rock (OAPR) and their effects on pH, available P and bioavailable Pb concentrations in the rhizosphere and bulk soils of mung bean plant were evaluated. Furthermore, the effects of these variant OAPR rates on Pb concentrations in plant parts, bioaccumulation factor (BAF) and translocation factor (TF) for Pb in grain and traits like productivity, the activities of antioxidant enzymes, and grain biochemistry were investigated. Results revealed that increasing rates of OAPR significantly increased pH values and available P while decreased bioavailable Pb concentrations in the rhizosphere over control. The highest dissolution of P in the rhizosphere was with 4 and 6% OAPR rates. As a result, the formation of insoluble Pb compounds affected on reduced Pb concentrations in shoots, roots, and grain in addition to lower grain BAF and TF values for Pb over control. Likewise, the highest plant productivity, improved grain biochemistry, high Ca and Mg concentrations, least oxidative stress, and enhanced soil alkaline phosphatase activity were found with 4 and 6% OAPR rates. The OAPR 4% rate is suggested for reducing grain Pb concentration, cell oxidative injury, and improving grain biochemistry in mung bean.

Keanekaragaman Mikrob Fungsional Rizosfer Nanas dengan Berbagai Tingkat Produktivitas

Functional microbes of rhizosphere play important roles in nutrient transformation and controlling disease as well as in supporting plant growth and development. However, there is no study on the role of functional microbes on pineapple productivity. The purpose of this study was to investigate the abundance and diversity of soil functional microbes at different growth phases at two levels of productivity and their correlations to disease incidence. The research process included sampling of pineapple rhizospheric soil from vegetative and generative phases pineapples at low and high plant productivity sites, observations of disease incidence, and isolations of functional microbes. Functional groups of bacteria were Azotobacter, phosphate-solubilizing bacteria, potassium-solubilizing bacteria, antibiotics-producing bacteria, IAA-producing bacteria, and chitinolytic bacteria. The soil sampling method was simple randomized sampling at 6 locations with an area of each location ± 5 ha with a depth of 20 cm. Rhizosphere were taken in plants grown in high productivity area (>60tons/ha) and low productivity area (<60 tons/ha) in vegetative and generative phases. The results showed that potassium-solubilizing bacteria, chitinolytic bacteria, and IAA-producing bacteria were more abundant during the generative phase compared to those during vegetative phase. While Azotobacter, phosphate-solubilizing bacteria, and antibiotic-producing bacteria were more predominant during vegetative phase at various crop productivy. Total density of microbes was higher in soil with high crop productivity than that in soil with low crop productivity. The abundance of chitinolytic bacteria and IAA-producing bacteria had negative correlation with disease caused by Erwinia chrysanthemi and Phytophthora cinnamomi.
 Keywords: chitinolytic bacteria, growth phase, IAA, pineapple disease

Effects of mowing regimes on above- and belowground biota in semi-arid grassland of northern China

Mowing is a widely used practice for haymaking in the semi-arid grassland of northern China. Yet, how it impacts above- and belowground biota and ultimately affects the grassland ecosystem is unclear. Here we address this question by investigating the effects of three mowing regimes (no mowing, mowing once per year, mowing twice every three years) on vegetation characteristics, soil properties, and microbial communities in semi-arid grassland of Inner Mongolia. Our results show that two types of mowing treatments preserve high plant productivity by increasing subordinate species. However, mowing once per year led to grassland degradation when applied over a seven-year period. Mowing twice every three years facilitates soil bacterial communities and microbial interactions by generating a nutrient-rich ecological niche, whereas mowing once per year negatively impacted them via lessen the substrate quality. Given its clear positive effects upon above- and belowground biota, mowing twice every three years is the most suitable, convenient management practice for sustaining plant species richness on this type of grassland, a finding which suggests that sustainable utilization of grassland resources can only be achieved by using modest rotation cutting practices.

Influence of food availability, plant productivity, and indigenous forest use on ranging behavior of the endangered samango monkey (Cercopithecus albogularis schwarzi), in the Soutpansberg Mountains, South Africa.

Understanding the determinants of ranging patterns in species susceptible to habitat fragmentation is fundamental for assessing their long-term adaptability to an increasingly human-dominated landscape. The aim of this study was to determine and compare the influence of ground-based food availability, remotely sensed plant productivity, and indigenous forest use on the ranging patterns of the endangered samango monkey (Cercopithecus albogularis schwarzi). We collected monthly ranging data on two habituated samango monkey groups, from February 2012 to December 2016, from our field site in the Soutpansberg Mountains, South Africa. We used linear mixed models to explore how food availability, plant productivity, and indigenous forest use influenced monthly ranging patterns, while controlling for group size, number of sample days and day length. We found that as more areas of high plant productivity (derived from remotely sensed EVI) were incorporated into the ranging area, both total and core monthly ranging areas decreased. In addition, both total ranging area and mean monthly daily path length decreased as more indigenous forest was incorporated into the ranging area. However, we found no effect of either ground-based food availability or remotely sensed plant productivity on ranging patterns. Our findings demonstrate the behavioral flexibility in samango monkey ranging, as samangos can utilize matrix habitat during periods of low productivity but are ultimately dependent on access to indigenous forest patches. In addition, we highlight the potential of using remotely sensed areas of high plant productivity to predict ranging patterns in a small ranging, forest-dwelling guenon, over ground-based estimates of food availability.

Growth of Striped Catfish Fingerlings (Pangasianodon hypophthalmus) in Aquaponic System with Fine Bubbles (FBs) Application

This study aims to determine the growth of Striped Catfish fingerlings (Pangasianodon hypophthalmus) and using Fine Bubbles (FBs) application with various pressures in the aquaponic system. The study was conducted at the Laboratory of Aquaculture, Ciparanje, Faculty of Fisheries and Marine Sciences, Padjadjaran University from 18th September to 18th October 2019. The method used in this study was the experimental method using Completely Randomized Design (CRD) with four treatments and three replicates. Treatment A: Control (without FBs), Treatment B: FBs with pressure 4.5 atm, Treatment C: FBs with pressure 5 atm, and Treatment D: FBs with pressure 5.5 atm. This research used water spinach as biofilter. The measured parameters in this study were fish growth, plant productivity, and water quality which includes levels of temperature, dissolved oxygen, nitrate, ammonia and phosphate. The results showed that the highest fish specific growth rate in treatment D is 6.68 ± 0.43%/day with a survival rate of 100 ± 0.00%, the highest plant productivity, with a stem length of 115.03 cm, a weight of 62.75 g, and leaf growth of 30 strands. While the water quality parameters including temperature, dissolved oxygen concentrations ranged from 24.2-27°C, 7.72-7.94 mg / l, nitrate 0.243-0.602 mg /, ammonia 0.001-0.010 mg / l and phosphate 0.147-0.229 mg / l respectively.

Nitrate assimilation pathway in higher plants: critical role in nitrogen signalling and utilization

The process of nitrate assimilation is a very crucial pathway for the sustainable growth and productivity of higher plants. This process is catalysed by two enzymes, nitrate reductase and nitrite reductase. Both the enzymes differ from each other with respect to their structural organisation, subcellular location, catalytic efficiencies and regulatory mechanisms. Nitrate reductase catalyses the rate limiting step of nitrate assimilation process. The genes and proteins of this enzyme have been isolated and characterised from many higher plants. The additional role of NR in the production of nitric oxide has been also reported in last several years. The reduced ammonium is assimilated into carbon skeleton, ?-ketoglutarate, by the concerted action of glutamine synthetase and glutamate synthase. Glutamine and glutamate are the transportable forms of nitrogen among various tissues and metabolic processes. The rate of nitrate assimilation is regulated by the rate of uptake of nitrate by nitrate transporters, availability of carbon skeleton, accumulation of nitrogenous end products, light and the rate of photosynthesis. The partitioning of metabolites and resources between carbon and nitrogen metabolism is an important factor for the growth and yield of plants. During the last several decades excess use of nitrogen fertiliser has caused environmental pollution. Efforts have been made to increase the nitrogen use efficiency of plants to reduce the cost on fertiliser and nitrate pollution, increase the productivity and protein content of several commonly used crops. This review discusses the process of nitrate assimilation and its interaction with the carbon metabolism.

Paleoenvironmental reconstruction using stable isotopes and trace elements from archaeological freshwater bivalve shell fragments in Northwest Patagonia, Argentina

Stable oxygen and carbon isotopes (18O and 13C) and the trace elements, manganese (Mn) and strontium (Sr) were analyzed in archaeological bivalve (Diplodon chilensis) shell fragments recovered from Parque Diana Cave, Patagonia, Argentina, to analyze the temporal trends of human occupation of the North Patagonia forest with climatic conditions recorded at regional scale but poorly known at local scale for this site. We established a stratigraphic sequence of thirteen 10 cm thick layers spanning the period c. 2370 BP to c. 580 BP and grouped these layers into three cultural components.According to this region's climate, with rain and snow concentrated in winter and dry summers, our data suggest that these components are contemporary with three climatic periods. A dry period indicated by high values of δ18Oshell, δ13Cshell and Sr/Ca ratio (Mn/Ca ratio does not show any significant trend), in the Lower component is associated with brief incursions of hunter-gatherers from the eastern steppe. In the Middle component, low δ18Oshell, δ13Cshell and Sr/Ca ratios, suggest a humid climate with increased supply of meteoric and/or melt-water along with terrestrial plants organic matter and soil carbonates to the river. According to the archaeological evidence, in this period, hunter gatherers from the Pacific coast and forest started to colonize the area across the Andes cordillera. At the beginning of the Upper component, which is mostly contemporary with the expression of the Medieval Climatic Anomaly (MCA), the proxies are not totally coincident but a tendency to progressively drier conditions could be inferred. Except for layer 4 for δ18Oshell and layer 5 for Sr/Ca ratio, δ18Oshell, δ13Cshell and Sr/Ca ratio show consistently high levels in the Upper than in the Middle component. In layer 5, δ18Oshell and δ13Cshell are elevated with respect to the Middle component while Sr/Ca ratio remains low. In layer 4, δ13Cshell and Sr/Ca ratio are high while δ18Oshell shows a negative peak. In layers 3 to 1, δ18Oshell, δ13Cshell and Sr/Ca ratio remain at high levels, indicating an arid-warm climate with high aquatic plant productivity, in coincidence with the expression of the MCA reported for this region in a partially contemporaneous period (1080–1250 AD). At this time, the occupation of the site by groups of the same origin as those present in the Middle component became permanent. Extensive and intensive use of local resources in this period can be inferred from the quality and quantity of artifacts recovered.

Species energy and Thermal Performance Theory predict 20-yr changes in ant community abundance and richness.

In an era of rapid climate change, and with it concern over insect declines, we used two theories to predict 20-yr changes in 34 North American ant communities. The ecosystems, from deserts to hardwood forests, were first surveyed in the 1990s. When resurveyed in 2016-2017, they averaged 1°C warmer with 200 g C·m-2 ·yr-1 higher plant productivity. Ant colony abundance changed from -49% to +61%. Consistent with Thermal Performance Theory, colony abundance increased with temperature increases<1°C, then decreased as a site's mean monthly temperature change increased up to +2.4°C. Consistent with Species Energy Theory, (1) ant abundance tracked changes in a measure of energy availability (net aboveground productivity, g C·m-2 ·yr-1 ) and (2) increases in colony abundance drove increases in local plot- and transect-level species richness but not that of Chao 2, an estimate of the size of the species pool. Even after accounting for these drivers, local species richness was still higher ~20yr after the original surveys, likely due to the increased activity of ant workers. These results suggest community changes are predictable using theory from geographical ecology, and that warming can first enhance but may ultimately decrease the abundance of this important insect taxon.

Plant Yield, Antioxidant Capacity and Essential Oil Quality of Satureja Mutica Supplied with Cattle Manure and Wheat Straw in Different Plant Densities

ABSTRACTSatureja mutica is a medicinally important plant, which may be affected by organic fertilizers and cultivation methods. To investigate the effect of cattle manure (30 ton/ha) and wheat straw (10 ton/ha) as organic fertilizers and plant density (80000, 40000, and 26666 plan ha−1), an experiment was carried out as split plot with three replications during 2017 and 2018 on plant yield, total phenol content (TPC), total flavonoid content (TFC), essential oil (EO) yield and composition of S. mutica in the rainfed condition. The results showed that the highest fresh weight yield (FWY) and dry weight yield (DWY) were observed in high plant density in second year. TPC in interaction of second year and cattle manure was higher than others. The greatest TFC was observed in plants supplied with interaction of second year and wheat straw. EO content and yield in plants treated with the interaction of second year and high plant density were higher compared to those in other plants. The GC/MS analysis showed that the main EO components were thymol, carvacrol, γ-terpinene and p-Cymene, representing different concentrations by using the organic fertilizers and plant densities. In summary, the use of cattle manure and high plant densities can result in higher plant production.

Inheritance and combining ability of persistence and drought recovery in smooth bromegrass (Bromus inermis L.)

Post-drought recovery, persistence and summer dormancy in smooth bromegrass (Bromus inermis L.) genotypes and the inheritance of these traits as affected by different prolonged water management regimes are very poorly understood. In this study, we evaluated first-generation half-sib families derived from the polycross of parental genotypes for phenological, agronomic and morphological traits in the field for 4 years (2011–2014) under normal and deficit irrigation regimes. In the fifth year (2015), we first withheld irrigation in both treatment regimes for 2 months, and then after re-watering we evaluated the post-drought recovery of the genotypes. We found that additive gene action alone played an important role in controlling most of the traits, but that both additive and non-additive gene effects played a role in the genetic control of forage yield. Post-drought recovery was positively correlated with previously measured morphological traits, establishment rate and spring growth, suggesting that recovery potential can be predicted through developing an index. The stability analysis on general combining ability and the principal component analysis clearly identified the superior and stable genotypes able to transmit both stability and high plant productivity to their progenies.

Biochemical and physiological aspects of chlorophyll breakdown

During leaf senescence and fruit ripening chlorophyll is broken down into nonfluorescent catabolites (NCCs). The chlorophyll degradation pathway includes a series of biochemical transformations ocurring sequentially in chloroplasts, cytosol and vacuoles. The path begins with enzymatic reduction of chlorophyll b to chlorophyll a. Next, the specific dechelatase and esterase remove the magnesium atom and the phytol chain resulting in the formation of pheophorbide a. In the next step, the porphyrin macroring is opened by pheophorbide a oxygenase and red catabolite reductase. The product of this transformation is an early fluorescent catabolite (pFCC), which after hydroxylation and species-specific modifications is imported into the vacuole. In acidic medium of the vacuole pFCC undergo isomerization to their respective colorless NCCs, which are final chlorophyll degradation products in higher plants. There are still no answers to a number of questions about the fate and significance of millions tons of chlorophyll catabolites released annually in the aquatic environment as a result of cellular senescence and death of phytoplankton. A few reports indicate that algae and cyanobacteria may metabolize their photosynthetic pigments in a similar way as higher plants do, however, the course of chlorophyll breakdown in these organisms has not been yet elucidated.