Flower Biomass Research Articles

Phyto-stimulating Effect of Paracetamol Biodestruction Product on Calendula Officinalis

Introduction. In recent years, there has been an increase in fundamental interest in the search for effective, including microbiological, methods for processing pharmaceutical waste to obtain new biologically active compounds on their basis. Our results showed that the product of bacterial degradation of paracetamol (BDP) exhibits pronounced stimulating properties in relation to medicinal plants of the families Plantaginaceae, Lamiaceae, Urticaceae, Linaceae and can be used as an inducer of the accumulation of biologically active substances in them.Aim. The purpose of this work is to study the effect of BDP on the dynamics of biomass accumulation and the content of flavonoids in the flowers of Calendula officinalis L., fam. Asteraceae in comparison with the control (water) and growth stimulator "Zircon".Materials and methods. BDP obtained on the basis of the Laboratory of Alkanotrophic Microorganisms Institute of Ecology and Genetics of Microorganism UB RAS (Perm). Calendula officinalis flowers collected from plants treated with BDP and Zircon growth stimulator were used to study the dynamics of dry biomass accumulation and changes in the content of flavonoids by the spectrophotometric method. For a comparative analysis of the intensity of the increase in the biomass of flowers during the treatment of plants with these agents, as well as to predict the accumulation of flavonoids, kinetic modeling was used.Results and discussion. The total biomass harvest of calendula officinalis flowers when treated with BDP increased by 55 %, and when treated with the Zircon growth stimulator, by 24 % compared to the control. The content of flavonoids in flowers when treated with these agents increased by 101 and 40 %, respectively. The dates for the beginning of the collection of calendula officinalis flowers in the conditions of the Western Urals were determined: with the use of the Zircon growth stimulator – from July 20, BDP – from August 1, without treatment with growth stimulants – from August 14. Both stimulants increase the end date of the collection of raw materials by 10 days.Conclusion. The product of bacterial degradation of paracetamol has a pronounced stimulating effect on calendula officinalis, significantly increasing the biomass of flowers and the content of flavonoids in them compared to the control (water) and growth stimulator "Zircon". With the use of kinetic modeling, the values of the parameters of the growth rate of the biomass of plant raw materials during the treatment of plants with these agents were established, a forecast was made for the accumulation of flavonoids, and the timing of the collection of calendula officinalis flowers in the conditions of the Western Urals was substantiated.

Complementary water and nutrient utilization of perianth structural units help maintain long floral lifespan in Dendrobium.

Most orchids have high ornamental value with long-lived flowers. However, the mechanisms by which orchids maintain floral longevity are poorly understood. Here, we hypothesized that floral longevity in Dendrobium is maintained by high resource investment and complementary water and nutrient utilization in different structural units of the perianth. To test this hypothesis, we determined which water- and nutrient-related traits are correlated with flower longevity in 23 Dendrobium species or cultivars, and examined variations of the related traits during flower development of one long-lived cultivar. We found that floral longevity was correlated with dry mass per unit area of perianths and total flower biomass, which indicates that maintaining floral longevity requires increased resource investment. During development of long-lived flowers, labella showed a high capacity for water storage and nutrient reutilization, which could partly remedy high water demand and biomass investment. Sepals and petals, in contrast, had stronger desiccation avoidance and higher metabolic activity with lower biomass investment. These findings indicate that Dendrobium flowers maintain longevity by complementary water and nutrient utilization strategies in the sepals, petals and labella, with labella consuming more water and nutrients to extend flower display, and sepals and petals using a more conservative strategy.

EFFICACY OF DIFFERENT FUNGICIDES TO CONTROL SOIL AND CORM-BORNE DISEASE OF SAFFRON (Crocus sativus L.) GROWN IN QUETTA, BALOCHISTAN, PAKISTAN

To check the efficacy of different fungicides to control soil and corm borne disease of saffron (Crocus sativus) by conducting experiment at Balochistan Agriculture Research and Development Center (BARDC) Quetta, Balochistan, Pakistan during the year 2019-2020. The corms were treated with one of the following fungicides; Copper Oxychloride, Cabriotop, Rovral, Vitavax Thiram, Acrobat MZ and Tanda. These corms were sown in a Randomized Complete Block Design (RCBD) along with control treatment (fungal-infected corms with no fungicide treatment). The results indicated that the positive effect of fungicides on the flower production (dry weight) of saffron was in the order of Acrobat MZ and Copper Oxychloride > Rovral and Vitavax Thiram > Cabriotop, Tanda and control (P < 0.05). The dry flower biomass of saffron under treatment of Acrobat MZ and Copper Oxychloride was ~ 3 and 4 times greater than the flower production of control treatment. The dry weight of stigma under treatments of Acrobat MZ and Copper Oxychloride was ~2 – 3 times greater than the control treatment (P < 0.05). All fungicides except Tanda significantly increased the length of stigma (2.98 – 2.82 cm) than control (2.65) (P < 0.05). Acrobat MZ also significantly increased the survival of croms than control treatment. These results demonstrate that corms treated with fungicides specifically with Acrobat MZ and Copper Oxychloride not only reduce the disease incidence and pathogen population in the soil, but also improved the certain growth parameters related to vegetative and reproductive parts of saffron.

Acclimation of Ecophysiological and Agronomic Traits to Increasing Growth Temperature in Three Cowpea Genotypes Grown in Anuradhapura, Sri Lanka

The future of food crop production is uncertain due to the negative effects of global warming. Cowpea is grown in warm environments including in Sri Lanka, where less is known about the potential acclimation of ecophysiological and agronomic traits to increasing temperatures. We evaluated the acclimation potential of yield components and ecophysiological traits of three recommended cowpea genotypes to the seasonal variation in growth temperature in Anuradhapura, Sri Lanka. This study was conducted at the Faculty of Agriculture, Rajarata University of Sri Lanka, in two consecutive seasons with average daytime temperatures of 30.4°C and 33.2°C. Three genotypes, Dhawala, Waruni, and MI-35, were tested in this study, and their rates of leaf photosynthesis and respiration at the 50% flowering stage and final yield parameters were measured at their respective average growth temperatures in both seasons. The total yield per hectare showed an average decrease of 16%, 17%, and 22% in the Dhawala, Waruni, and MI-35 genotypes at high average growth temperature, respectively. These reductions were associated with the reduction in the number of seeds per pod, hundred seed weight, and number of pods per plant, suggesting that there could be an among-genotype variation in flower abscission, fertilization, and biomass partitioning during the season in which the average growth temperature was high. In the season with high average growth temperature, genotype Dhawala showed an increased carbon gain per unit carbon loss and increased water use efficiency compared to MI-35 and Waruni genotypes. Therefore, genotype Dhawala is a better candidate than MI-35 and Waruni genotypes in the face of global warming, which may be considered in further breeding programs and market preferences. More work is proposed to examine the patterns of biomass partitioning and radiation use efficiency in three cowpea genotypes at elevated temperatures.

Sustainable and Green Synthesis of Waste-Biomass-Derived Carbon Dots for Parallel and Semi-Quantitative Visual Detection of Cr(VI) and Fe3.

Carbon dot (CD)-based multi-mode sensing has drawn much attention owing to its wider application range and higher availability compared with single-mode sensing. Herein, a simple and green methodology to construct a CD-based dual-mode fluorescent sensor from the waste biomass of flowers of wintersweet (FW-CDs) for parallel and semi-quantitative visual detection of Cr(VI) and Fe3+ was firstly reported. The FW-CD fluorescent probe had a high sensitivity to Cr(VI) and Fe3+ with wide ranges of linearity from 0.1 to 60 µM and 0.05 to 100 µM along with low detection limits (LOD) of 0.07 µM and 0.15 µM, respectively. Accordingly, the FW-CD-based dual-mode sensor had an excellent parallel sensing capacity toward Cr(VI) and Fe3+ with high selectivity and strong anti-interference capability by co-using dual-functional integration and dual-masking strategies. The developed parallel sensing platform was successfully applied to Cr(VI) and Fe3+ quantitative detection in real samples with high precision and good recovery. More importantly, a novel FW-CD-based fluorescent hydrogel sensor was fabricated and first applied in the parallel and semi-quantitative visual detection of Cr(VI) and ferrous ions in industrial effluent and iron supplements, further demonstrating the significant advantage of parallel and visual sensing strategies.

Evaluating the Growth-promoting Effects of Microbial Biostimulants on Greenhouse Floriculture Crops

Microbial biostimulants can promote ornamental plant growth during production and improve crop performance under abiotic stresses. Even though biostimulants have shown potential in many agricultural applications, the effectiveness and specificity of many products are not well understood. The objective of this study was to analyze the growth-promoting effects of microbial biostimulants during the greenhouse production of floriculture crops. We evaluated 13 biostimulant products in greenhouse-grown zinnia (Zinnia elegans ‘Magellan Ivory’) and petunia (Petunia ×hybrida ‘Carpet White’) at low fertility (one-third of the optimal fertilizer concentration). Biostimulant products 1 and 2 containing multiple species of beneficial bacteria and fungi, and product 10 containing Bacillus subtilis QST 713, were found to increase various aspects of plant growth, including the growth index, leaf chlorophyll content (SPAD index), and shoot biomass. Both flower biomass and numbers were greater in petunia treated with product 1, and leaf size increased in zinnia treated with products 1, 2, and 10. Plants treated with these effective biostimulants at low fertility had similar or better growth and quality than untreated plants grown under optimal fertility. The concentration of various nutrient elements in leaves was higher in zinnia plants treated with biostimulant products 1, 2, or 10 compared with the negative control. Some putative mechanisms for biostimulant effectiveness, the possible reasons for biostimulant ineffectiveness, and the potential for using biostimulants as a sustainable cultural strategy are discussed. This study provides useful information about microbial biostimulant effectiveness, which is important for the development and utilization of biostimulants in the greenhouse production of floriculture plants.

Co-existence Between Two Leaf-Feeding Biological Control Agents of Lantana camara Alters Their Herbivory Under Semi-field Conditions.

Interaction between two biological control agents released against Lantana camara L. (sensu lato) (Verbenaceae) was studied in replicated semi-field plots. Caged plants under semi-field conditions were inoculated with Uroplata girardi Pic (Coleoptera: Chrysomelidae) and Ophiomyia camarae Spencer (Diptera: Agromyzidae), either alone or in combination, to investigate the extent to which co-infestation of the two agents affects the reproductive capacity and growth of their host. At the end of the trial, both single and combined attacks by the two agents had no effect on stem diameter, stem height, and canopy width. However, uncaged control plants were heavily attacked by Teleonemia scrupulosa Stål (Hemiptera: Tingidae), and therefore became significantly shorter than all the caged plants in all the treatments. When confined alone, feeding damage by O. camarae resulted in higher reduction of fruit and flower biomass relative to that caused by U. girardi alone. However, when confined alone, U. girardi caused higher reductions in leaf density and fruit biomass than when combined with O. camarae. Single attack by O. camarae caused higher reduction in flower biomass than simultaneous attack by both agents. Above-ground biomass of all single and combined treatment plants were significantly lower than those of the caged control plants. Uncaged control plants exposed to heavy attack by T. scrupulosa did not produce flowers and fruits, and their above-ground biomass was significantly lower than those of caged control plants. Overall, the study showed that simultaneous attack by the two herbivores alters their herbivory, thereby affecting reproductive capacity and growth of their host.

Comparative Assessment of the Phytochemical Composition and Biological Activity of Extracts of Flowering Plants of Centaurea cyanus L., Centaurea jacea L. and Centaurea scabiosa L.

The data on the phytochemical composition and biological activity for flowering plant extracts of the genus Centaurea (Knapweed)—cornflower (Centaurea cyanus L.), brown knapweed (Centaurea jacea L.), and greater knapweed (Centaurea scabiosa L.), which are typical representatives of the flora in the middle belt of the Russian Federation, were obtained. For the first time, biologically active substances such as pyranone, coumaran (2,3-dihydrobenzofuran), and 5-hydroxymethylfurfural were identified in ethanol and methanol extracts of Centaurea scabiosa L. by gas chromatography–mass spectrometry. Catechol and α-amyrin were the major components of the ethanol extract from Centaurea cyanus L., and flavone was the major component of Centaurea jacea L. flower extract. The greatest antimicrobial activity against phytopathogens was detected in Centaurea scabiosa L. when extracting freshly harvested flower biomass with methyl tert-butyl ether at room temperature: the minimum inhibitory concentrations were 60–120 µg/mL, the minimum fungicidal concentration was 120 µg/mL, and the minimum bactericidal concentration was 250 µg/mL. The low antioxidant activity of the studied plant extracts was established using the maximum values of Centaurea jacea L. Ethanol extract of Centaurea cyanus L. flowers had low antimicrobial and antioxidant activity. The extracts showed no phytotoxicity to garden cress germination but inhibited the growth of juvenile plants, especially roots. The greatest phytotoxic effect was revealed with methyl tert-butyl ether, where the depression of growth indicators was 35% or more.

Holm oak fecundity does not acclimate to a drier world.

Climate change might impact tree fecundity by altering the relative influences of meteorological and physiological drivers, and by modifying resource investment in reproduction. Using a 13-yr monitoring of Quercus ilex reproduction in a rainfall exclusion experiment, we analysed the interactive effects of long-term increased aridity and other environmental drivers on the inter-annual variation of fecundity (male flower biomass, number of initiated and mature fruits). Summer-autumn water stress was the main driver of fruit abortion during fruit growth. Rainfall exclusion treatment strongly reduced the number of initiated and mature fruits, even in masting years, and did not increase fruit tolerance to severe drought. Conversely, the relative contribution of the meteorological and physiological drivers, and the inter-annual variability of fruit production were not modified by rainfall exclusion. Rather than inducing an acclimation of tree fecundity to water limitation, increased aridity impacted it negatively through both lower fruit initiation due to changes in resource allocation, and more severe water and resource limitations during fruit growth. Long-term increased aridity affected tree reproduction beyond what is expected from the current response to inter-annual drought variations, suggesting that natural regeneration of holm oak forest could be jeopardised in the future.

Appropriateness of waste jasmine flower for bioethanol conversion with enzymatic hydrolysis: sustainable development on green fuel production.

Utilized and waste jasmine flower contains a high portion of organic carbohydrate and other organic acids, making it a suitable substrate for bioethanol production. This study was designed to estimate the prospective of waste jasmine flower biomass applied with chemical (alkaline) and thermal pretreatment applied on samples through bioethanol production efficiencies. Therefore, pretreatment and enzymatic hydrolysis are directed to disrupt the complex cell wall layer and improve the accessibility towards polysaccharide fraction. Also, applying response surface methodology tools during fermentative bioethanol production to study the interactive effects of different bioprocess variables for higher bioethanol yield in batch small and large scale model is discussed. The immobilized yeast between jasmine found that jasmine sugar utilization was 50%. The jasmine flower's ethanol production was 6.54g/L and after distillation of jasmine was 31.40g/L at pH 4.5. Results showed that this immobilized yeast method could be successfully used for bioethanol production from waste jasmine flower.

Non-Thermal Plasma Treatment Influences Shoot Biomass, Flower Production and Nutrition of Gerbera Plants Depending on Substrate Composition and Fertigation Level.

Non-thermal plasma (NTP) appears a promising strategy for supporting crop protection, increasing yield and quality, and promoting environmental safety through a decrease in chemical use. However, very few NTP applications on containerized crops are reported under operational growing conditions and in combination with eco-friendly growing media and fertigation management. In this work, NTP technology is applied to the nutrient solution used for the production of gerbera plants grown in peat or green compost, as an alternative substrate to peat, and with standard or low fertilization. NTP treatment promotes fresh leaf and flower biomass production in plants grown in peat and nutrient adsorption in those grown in both substrates, except for Fe, while decreasing dry plant matter. However, it causes a decrease in the leaf and flower biomasses of plants grown in compost, showing a substrate-dependent effect under a low fertilization regime. In general, the limitation in compost was probably caused by the high-substrate alkalinization that commonly interferes with gerbera growth. Under low fertilization, a reduction in the photosynthetic capacity further penalizes plant growth in compost. A lower level of fertilization also decreases gerbera quality, highlighting that Ca, Mg, Mn, and Fe could be reduced with respect to standard fertilization.

Silencing ATG6 and PI3K accelerates petal senescence and reduces flower number and shoot biomass in petunia

Petal senescence is a form of developmental programmed cell death (PCD) that is regulated by internal and environmental signals. Autophagy, a metabolic pathway that regulates intercellular nutrient recycling, is thought to play an important role in the regulation of petal senescence-associated PCD. To characterize the function of two central autophagy genes in petal senescence, we down-regulated Autophagy Gene 6 (PhATG6) and Phosphoinositide 3-Kinase (PhPI3K) using Virus-Induced Gene Silencing (VIGS) in Petunia × hybrida. The silencing of PhATG6 and PhPI3K accelerated petal senescence, thereby reducing flower longevity. Both PhATG6- and PhPI3K-silenced petunias had reduced flower numbers, flower biomass, and vegetative shoot biomass. These phenotypes were intensified when plants were grown under low nutrient conditions. Additionally, two important regulators of senescence, an ethylene biosynthesis gene (PhACS) and a type I metacaspase gene (PhMC1), were suppressed in senescing petals of PhATG6- and PhPI3K-silenced plants. In conclusion, our study identified PhATG6 and PhPI3K as negative regulators of flower senescence and demonstrated the influence of nutrient limitation on the function of autophagy during petal senescence. Our study also found that autophagy genes potentially influence the transcriptional regulation of metacaspases and ethylene biosynthetic genes during petal senescence. The results of this project will be fundamental for future studies of petal senescence and will provide genetic information for future crop improvement.

A friendly-environmental strategy: application of arbuscular mycorrhizal fungi to ornamental plants for plant growth and garden landscape

The demand for ornamental plants is increasing due to urban greening and rural construction, while the growing environment of plants, especially the soil environment, is deteriorating. Hence, sustainable methods of ornamental plant cultivation need to be developed quickly. The application of arbuscular mycorrhizal fungi (AMF) to ornamental plants can be one of the eco-friendly ways to achieve the objective. Soil AMF establish mycorrhizal symbiosis with roots of ornamental plants, which can develop a marvelous mycorrhizal mycelium network in the rhizosphere to stimulate nutrient and water acquisition of host plants. Numerous researches have proven that AMF improved the quality of ornamental plants, like fruit yield, height, biomass, seed quality, the size and number of flowers, leaf, and root. In addition, mycorrhizal fungi also improve nutrient uptake and endogenous hormone balance of host plants. Another important function of AMF is to regulate the physiological, biochemical, and molecular responses of host plants to adversity, including drought stress, temperature stress, heavy-metal stress, and insect and disease stress. From the perspective of the ecological garden landscape, AMF richness would maintain plant abundance, nutrient and energy balance, and higher productivity in normal and soil environment stress, thus, establishing a friendly-environmental ecosystem. This review also provides the basis to exploit and improve the commercial application of AMF in ornamental plants in the future.

Dataset comparing the growth of fodder crops and soil structure dynamics in an industrial biosludge amended arid soil.

The dataset in this work compares the response of two fodder crops, alfalfa (Medicago sativa) and buffel grass (Cenchrus ciliaris), to industrial biosludge amendment of an arid soil in the State of Qatar. It also evaluates the response of soil structure parameters in the biosludge-amended soils containing the different fodder crops. The dataset relates to our previously published works detailed subsequently. The underlying data comparing the water storage capacity and pore structure evolution of the planted soils treated with 0.75, 1.5, and 3% biosludge contents, which showed good outcomes in the companion articles, alongside soil only and soil-fertilizer controls, are presented. These are shown in terms of the percentage of irrigation water leached, and variations in the logarithmic mean T2 (i.e., T2LM - a proxy for mean pore size) and cumulative porosity, respectively. Data on plant growth parameters such as the number of days to flowering, plant height, and aboveground fresh biomass weight in individual replicates of the different treatments as a percentage of the soil-fertilizer control are also shown. The dataset shows the different responses of both plants and the planted soils to amendments with industrial biosludge from the wastewater treatment plant of a gas-to-liquid (GTL) plant.

Biomass, carbon and nutrient stocks in different categories of rose (Rosa spp.) for optimizing input use

The present study was carried out at ICAR-IIHR, Bengaluru to assess biomass accumulation, nutrient distribution, nutrient/water/energy use, plant available soil nutrients and carbon storage in different categories of roses in open-grown and protected systems. In open-grown roses, biomass of leaves, stalk and flowers represented 31.9%, 41.1% and 26.95%, respectively. In protected condition, flower biomass accounted for 17.62% of the total compared to leaf (51.0%), and stalk biomass (31.4%). The carbon stocks in plant biomass and soil accounted for 22% and 78% of total in open-grown rose system. In protected condition, plant and soil carbon stocks accounted for 11% and 89% of the total carbon stocks. Soil carbon stocks increased from 2.214 to 3.958 kg m−2 during 4-year period in open field. In protected condition, soil carbon stock was increased from 3.315 to 5.104 kg m−2 registering an increase of 1.789 kg m−2. In rose production system, leaves registered highest levels of macronutrients while flowers acquired more micronutrients. The water use was 45% higher in protected cultivation (344 L yr−1 m−2) than in open condition (232 L yr−1 m−2). Based on nutrient use indicators and energy use of nutrient inputs, Arka Savi and Arka Swadesh were identified as efficient nutrient use and energy use (74.6% and 37.3%) genotypes in open and protected conditions, respectively. Plant available nutrient stocks in soil were optimum to above optimum in rose system. The results imply that precision nutrient application is most important to save inputs/energy, avoid environmental pollution and to develop sustainable land use system.

The maleness of larger angiosperm flowers

Flower biomass varies widely across the angiosperms. Each plant species invests a given amount of biomass to construct its sex organs. A comparative understanding of how this limited resource is partitioned among primary (male and female structures) and secondary (petals and sepals) sexual organs on hermaphrodite species can shed light on general evolutionary processes behind flower evolution. Here, we use allometries relating different flower biomass components across species to test the existence of broad allocation patterns across the angiosperms. Based on a global dataset with flower biomass spanning five orders of magnitude, we show that heavier angiosperm flowers tend to be male-biased and invest strongly in petals to promote pollen export, while lighter flowers tend to be female-biased and invest more in sepals to insure their own seed set. This result demonstrates that larger flowers are not simple carbon copies of small ones, indicating that sexual selection via male-male competition is an important driver of flower biomass evolution and sex allocation strategies across angiosperms.

Impacts of soil properties and functional diversity on the performance of invasive plant species Solidago canadensis L. on post-agricultural wastelands

Amongst the numerous consequences of the rapid development of agriculture and urbanization, biological invasions are highlighted as having the biggest impact on the functioning of ecosystems. One of the alien plant species, considered in Europe and Asia to be highly invasive, is Solidago canadensis L.; and its impact on the functioning of ecosystems has been studied in numerous respects. However, knowledge about how the physico-chemical parameters of soils and biotic interactions between species shape the performance of S. canadensis in a transformed landscape is still insufficient. The aim of this study was to assess how complex soil abiotic conditions and the functional diversity of co-occurring vegetation shape the performance of S. canadensis on the wastelands abandoned by agriculture. Apart from detailed investigations of soil properties and S. canadensis biomass, to achieve our study aims, we used parameters of functional diversity, which allowed us to identify the main ecological processes determining the community assembly processes. Under higher contents of loamy fractions in soil, but lower functional richness in surroundings, S. canadensis achieved larger cover. Alongside increasing functional richness and dispersion in co-occurring vegetation, this species has demonstrated sturdy attributes when competing for water and nutrients, expressed by a higher production of rhizomes and roots. Under elevated zinc and lead levels, as well as higher functional evenness in the surroundings, the flower biomass decreased, while the biomass of stems increased. Thus, S. canadensis exhibits a highly adaptive capacity to grow in soils contaminated by heavy metals, due to the buffer properties and life strategies allowing the use of resources absorbed in loamy soils. Environmental factors seem to be more responsible for the shaping of the performance and for the colonization success of S. canadensis than biotic interactions with plants occurring in the surroundings.

Irrigation and nitrogen application affect Greek oregano (Origanum vulgare ssp. hirtum) dry biomass, essential oil yield and composition

Oregano is a perennial crop native to the mountains, which has been extensively cultivated in the last decade. Due to the growing interest in oregano cultivation, the aim of this study was to investigate the effect of irrigation and nitrogen fertilization on the yield of Greek oregano and the production of essential oil in order to increase the harvested yield without reducing the quality of the product. For the purposes of the study, field experiments were established in 2016 and 2017 using a factorial split-plot experimental design with main factor irrigation (I1: rainfed, I2: 100 % ETo) and sub factor nitrogen fertilization (N1: 0, N2: 150, and N3: 300 kg ha−1) under four replicates. Total yield measured by final samplings where plants were cut at 5–8 cm above ground. Essential oil content was determined, using a Clevenger-type distillation apparatus. Irrigation had not a significant effect on yield, with irrigated treatments producing almost the same yield with the rainfed treatments (3650 and 3250 kg ha-1, respectively), probably due to the satisfactory precipitation during the growing period. In addition, nitrogen fertilization had a significant effect on yield and on essential oil. The higher yield and essential oil production were found for the irrigated and fertilized with the higher nitrogen testing amount (I2N3) treatment (4750 and 275 kg ha-1 dry leaves and flower biomass and essential oil, respectively). Therefore, Greek oregano seems to be a promising cultivation in areas characterized by a typical Mediterranean climate with satisfactory precipitation (>250 mm) during growth period, characterized by satisfactory yields.

Effects of elevated temperature and CO2 concentration on floral development and sex differentiation in Morus alba L.

Elevated temperature, elevated CO2 concentration, and their combination significantly promoted the number and biomass of female mulberry (Morus alba L.) flowers, but the opposite is true for males. This paper demonstrates that male mulberry trees would suffer more negative effects on floral development and differentiation under global warming. With the ongoing intensification of global warming, flower formation has attracted widespread interest because it is particularly vulnerable to the effects of environmental factors. However, current knowledge of floral development regarding gender and sex differentiation under elevated temperature, CO2 concentration, and their combination remains limited. The aims of this study were to assess how sex-related differences in the morphology, biomass, and carbon (C) and nitrogen (N) contents of flowers respond to elevated temperature and CO2 concentration. Morus alba L. saplings (monoecious plants) were subjected to two temperature conditions (ambient vs. ambient + 2 °C) and two CO2 regimes (ambient vs. ambient + 380 ppm CO2) in growth chambers for 18 months growth, and differences in flowering phase, sex ratio, floral morphology and biomass, as well as total carbon and nitrogen of male and female inflorescences were investigated. Elevated temperature, elevated CO2 concentration, and their combination significantly increased the number and biomass of female inflorescences but decreased the number and biomass of male inflorescences. Furthermore, the combination of elevated temperature and CO2 concentration significantly decreased ovary length and C/N ratio of female flowers and the fresh weight of male flowers. Additionally, C/N ratio was negatively related to morphological traits of male inflorescences but positively related to tepal length of female flowers. These findings indicate that global warming may affect floral development and sex differentiation in mulberry and that the male inflorescences of M. alba may suffer more negative effects than female inflorescences with respect to flower number, biomass, and morphological development.

Roses Growth and Flowering Responding to Concentration and Frequency of Seaweed (Sargassum crassifolium L.) Liquid Extract Application

Rose is a popular cut flower in Sri Lanka and mainly cultivated for the export market. An experiment was conducted at the Crop Farm, Eastern University, Sri Lanka to assess the effects of seaweed liquid extract on growth and flowering of roses (Rosa sp.) from June to September 2018. Seven treatments of seaweed liquid extract applications (10% once a week (T1), 10% twice a week (T2), 20% once a week (T3), 20% twice a week (T4), 30% once a week (T5), 30% twice a week (T6) and distilled water (T7- control)) were applied at completely randomized design with ten replications. Plant height, leaf area, plant biomass and number of flowers were significantly higher in T3. Once a week application of 20% seaweed liquid extract had the potential to increase the plant height, leaf area, plant biomass, number of flowers and dry weight of flowers in this experiment. It might be due to the presence of nutrients and the growth promoters in the S. crassifolium L. seaweed extract and optimum concentration of seaweed extract received by plants at T3.From this experiment, it could be concluded that once a week application of 20% seaweed liquid extract is suitable for promoting growth and flowering of roses.