Increased Leaf Area Research Articles

In vitro regeneration, photomorphogenesis and light signaling gene expression in Hydrangea quercifolia cv. 'Harmony' under different LED environments.

Plant growth regulators, sucrose concentration, and light quality significantly impact in vitro regeneration of 'Harmony'. Blue light promotes photomorphogenesis by enhancing light energy utilization, adjusting transcription of light signal genes, and altering hormone levels. Hydrangea quercifolia cv. 'Harmony', celebrated for lush green foliage and clusters of white flowers, has been extensively researched for its regenerative properties. Regeneration in stem segments, leaves, and petioles is facilitated by exogenous auxin and cytokinins (CTKs), with the concentration of sucrose (SC) being a key determinant for shoot regeneration from leaves. The study also highlights the significant impact of light conditions on photomorphogenesis. With an increase in the proportion of red (R) light, there is an inhibitory effect, leading to a reduction in leaf area, a decrease in the quantum yield of PSII (ΦPSII), and an increase in non-photochemical quenching (ΦNPQ) and non-regulated energy dissipation in PSII (ΦNO). Conversely, blue (B) light enhances growth, characterized by an increase in leaf area, elevated ΦPSII, and stable ΦNPQ and ΦNO levels. Additionally, B light induces the upregulation of HqCRYs, HqHY5-like, HqXTH27-like, and HqPHYs genes, along with an increase in endogenous CTKs levels, which positively influence photomorphogenesis independent of HqHY5-like regulation. This light condition also suppresses the synthesis of endogenous gibberellins (GA) and brassinosteroids (BR), further facilitating photomorphogenesis. In essence, B light is fundamental in expediting photomorphogenesis in 'Harmony', demonstrating the vital role in plant growth and development.

In situ short-term responses of Amazonian understory plants to elevated CO2.

The response of plants to increasing atmospheric CO2 depends on the ecological context where the plants are found. Several experiments with elevated CO2 (eCO2) have been done worldwide, but the Amazonian forest understory has been neglected. As the central Amazon is limited by light and phosphorus, understanding how understory responds to eCO2 is important for foreseeing how the forest will function in the future. In the understory of a natural forest in the Central Amazon, we installed four open-top chambers as control replicates and another four under eCO2 (+250 ppm above ambient levels). Under eCO2, we observed increases in carbon assimilation rate (67%), maximum electron transport rate (19%), quantum yield (56%), and water use efficiency (78%). We also detected an increase in leaf area (51%) and stem diameter increment (65%). Central Amazon understory responded positively to eCO2 by increasing their ability to capture and use light and the extra primary productivity was allocated to supporting more leaf and conducting tissues. The increment in leaf area while maintaining transpiration rates suggests that the understory will increase its contribution to evapotranspiration. Therefore, this forest might be less resistant in the future to extreme drought, as no reduction in transpiration rates were detected.

Quantifying water-use efficiency in plant canopies with varying leaf angle and density distribution.

Variation in architectural traits related to the spatial and angular distribution of leaf area can have considerable impacts on canopy-scale fluxes contributing to water-use efficiency (WUE). These architectural traits are frequent targets for crop improvement and for improving the understanding and predictions of net ecosystem carbon and water fluxes. A three-dimensional, leaf-resolving model along with a range of virtually generated hypothetical canopies were used to quantify interactions between canopy structure and WUE by examining its response to variation of leaf inclination independent of leaf azimuth, canopy heterogeneity, vegetation density and physiological parameters. Overall, increasing leaf area index (LAI), increasing the daily-averaged fraction of leaf area projected in the sun direction (Gavg) via the leaf inclination or azimuth distribution and increasing homogeneity had a similar effect on canopy-scale daily fluxes contributing to WUE. Increasing any of these parameters tended to increase daily light interception, increase daily net photosynthesis at low LAI and decrease it at high LAI, increase daily transpiration and decrease WUE. Isolated spherical crowns could decrease photosynthesis by ~60 % but increase daily WUE ≤130 % relative to a homogeneous canopy with equivalent leaf area density. There was no observed optimum in daily canopy WUE as LAI, leaf angle distribution or heterogeneity was varied. However, when the canopy was dense, a more vertical leaf angle distribution could increase both photosynthesis and WUE simultaneously. Variation in leaf angle and density distributions can have a substantial impact on canopy-level carbon and water fluxes, with potential trade-offs between the two. These traits might therefore be viable target traits for increasing or maintaining crop productivity while using less water, and for improvement of simplified models. Increasing canopy density or decreasing canopy heterogeneity increases the impact of leaf angle on WUE and its dependent processes.

PRODUCTIVITY OF ELEPHANT GRASS (Pennisetum purpureum) PLANTED WITH LEGUMINOSE AT VARIOUS DOSAGES OF BIOORGANIC FERTILIZER


 
 
 The purpose of this study was to determine the productivity of elephant grass (Pennisetum purpureum) planted with leguminosae at various doses of bioorganic fertilizers. This study used a completely randomized design with two factorial patterns. The first factor was the type of leguminosae (T= without leguminosae; R= Arachi pintoi; L= Alysicarpus vaginalis; and the second factor was the dose of bioorganic fertilizer (D0= 0 kg Nha-1; D1= 100 kg Nha-1; D2= 200 kg Nha-1; and D3= 300 kg Nha-1) There were 12 treatment combinations, each treatment was repeated 5 times so that it consisted of 60 experimental units. The observed variables included growth, yield and growth characteristics variable. The results showed that there was no interaction between leguminous species and fertilizer dosage, both leguminous species only increased leaf area per pot, bioorganic fertilizer D1 and D2 doses tended to increase, while D3 dose increased leaf dry weight, total forage dry weight, and leaf area per pot of elep- hant grass (Pennisetum purpureum). It was concluded that the type of leguminous did not affect the productivity of elephant grass, the dose of bioorganic fertilizer increased crop yields, the highest yields at a dose of 300 kg Nha-1 bioorganic fertilizer.
 
 

Increased leaf area index and efficiency drive enhanced production under elevated atmospheric [CO2 ] in a pine-dominated stand showing no progressive nitrogen limitation.

Enhancement of net primary production (NPP) in forests as atmospheric [CO2 ] increases is likely limited by the availability of other growth resources. The Duke Free Air CO2 Enrichment (FACE) experiment was located on a moderate-fertility site in the southeastern US, in a loblolly pine (Pinus taeda L.) plantation with broadleaved species growing mostly in mid-canopy and understory. Duke FACE ran from 1994 to 2010 and combined elevated [CO2 ] (eCO2 ) with nitrogen (N) additions. We assessed the spatial and temporal variation of NPP response using a dataset that includes previously unpublished data from 6 years of the replicated CO2 × N experiment and extends to 2 years beyond the termination of enrichment. Averaged over time (1997-2010), NPP of pine and broadleaved species were 38% and 52% higher under eCO2 compared to ambient conditions. Furthermore, there was no evidence of a decline in enhancement over time in any plot regardless of its native site quality. The relation between spatial variation in the response and native site quality was suggested but inconclusive. Nitrogen amendments under eCO2 , in turn, resulted in an additional 11% increase in pine NPP. For pine, the eCO2 -induced increase in NPP was similar above- and belowground and was driven by both increased leaf area index (L) and production efficiency (PE = NPP/L). For broadleaved species, coarse-root biomass production was more than200% higher under eCO2 and accounted for the entire production response, driven by increased PE. Notably, the fraction of annual NPP retained in total living biomass was higher under eCO2 , reflecting a slight shift in allocation fraction to woody mass and a lower mortality rate. Our findings also imply that tree growth may not have been only N-limited, but perhaps constrained by the availability of other nutrients. The observed sustained NPP enhancement, even without N-additions, demonstrates no progressive N limitation.

Mustard ‘Amara’ Benefits from Superelevated CO2 While Adapting to Far-red Light Over Time

Compared with the ambient Earth carbon dioxide concentration (≈415 μmol⋅mol–1), the International Space Station has superelevated carbon dioxide (≈2800 μmol⋅mol–1), which can be a stressor to certain crops. Far-red light can drive plant photosynthesis and increase extension growth and biomass. However, the effects of far-red light under superelevated carbon dioxide are unclear. We grew hydroponic mustard (Brassica carinata) ‘Amara’ seedlings in four growth chambers using a randomized complete block design with two carbon dioxide concentrations (415 and 2800 μmol⋅mol–1), two lighting treatments, and two blocks at temperature and relative humidity set points of 22 °C and 40%, respectively. Each growth chamber had two lighting treatments at the same total photon flux density of 200 μmol⋅m–2⋅s–1. Under the same blue and green light at 50 μmol⋅m–2⋅s–1 each, plants received either red light at 100 μmol⋅m–2⋅s–1 or red + far-red light at 50 μmol⋅m–2⋅s–1 each. At day 15 after planting, far-red light did not influence shoot fresh or dry mass at 415 μmol⋅mol–1 carbon dioxide, but decreased both parameters by 22% to 23% at 2800 μmol⋅mol–1 carbon dioxide. Increasing the carbon dioxide concentration increased shoot fresh and dry mass 27% to 49%, regardless of the lighting treatment. Far-red light decreased leaf area by 16% at 2800 μmol⋅mol–1 carbon dioxide, but had no effect at 415 μmol⋅mol–1 carbon dioxide. Increasing the carbon dioxide concentration increased leaf area by 21% to 33%, regardless of far-red light. Regardless of the carbon dioxide concentration, far-red light promoted stem elongation and decreased chlorophyll concentrations by 39% to 42%. These responses indicate far-red light elicited a crop-specific shade avoidance response in mustard ‘Amara’, increasing extension growth but decreasing leaf area, thereby reducing light interception and biomass. In addition, carbon dioxide enrichment up to 2800 μmol⋅mol–1 increased the biomass of mustard ‘Amara’ but decreased the biomass of other crops, indicating crop-specific tolerance to superelevated carbon dioxide. In conclusion, mustard ‘Amara’ seedlings benefit from superelevated carbon dioxide, but exhibit growth reduction under far-red light under superelevated carbon dioxide.

Dry Direct-Seeded Rice Yield and Water Use Efficiency as Affected by Biodegradable Film Mulching in the Northeastern Region of China

In the realm of agriculture, biodegradable films are emerging as a promising substitute for traditional polyethylene (PE) films. Despite their potential, there has been a notable lack of extensive research on their effectiveness in the context of dry direct-seeded rice cultivation. Addressing this gap, a comprehensive biennial study was conducted in the northeastern regions of China, focusing on the ‘Baonong 5’ rice variety. This study meticulously compared three distinct cultivation methods: (1) employing biodegradable film mulching, (2) using conventional plastic film mulching, and (3) cultivating without any mulch. The findings revealed that biodegradable film mulching significantly enhanced soil moisture control, increased leaf area, and improved rice yield and water utilization efficiency (p < 0.05) compared to the plots without mulch. Notably, there was no marked difference in outcomes between the plastic film mulching and the unmulched plots. This research underscores the profound benefits of biodegradable film in rice cultivation, particularly from an environmental sustainability perspective. This innovative method not only boosts agricultural productivity but also addresses critical environmental challenges like climate change and water conservation. The application of biodegradable mulch has proven to be remarkably effective in improving irrigation efficiency and crop water conservation, leading to enhanced rice development and higher yields. The study recorded a substantial increase in water productivity—30% in 2021 and between 52.85% and 60% in 2022—compared to traditional cultivation practices. Furthermore, the use of biodegradable mulch resulted in significantly higher rice yields than the non-mulched plots, thus contributing to increased profitability. Such methods not only yield higher crop outputs but also mitigate environmental issues like water pollution and help alleviate prevalent water shortages in rice farming.

Effects of applying lime and phosphogypsum in soybean and wheat nutrition

This study aimed to assess the nutritional status of soybean and wheat and the relationship with grain yield and biometric components after lime and phosphogypsum (GY) reapplication. Treatments consisted of two lime application methods, surface liming and incorporated liming, to different levels of base saturation (BS) (44, 70, and 90%), in addition to surface liming to 70% BS associated with a standard dose (70GY1) or double dose (70GY2) of GY. Treatments were applied in 2012 and reapplied in 2016. The results refer to the 2018/2019 soybean season and the 2019 wheat season. Lime + GY treatment increased leaf area, plant height, leaf dry matter, and stem dry matter in soybean but had no effect on specific leaf area (235.4 cm2 g−1), stem diameter (6.08 mm), number of pods per plant (71.7), grain number per plant (165), or thousand grain weight (117 g). Liming to 90% BS reduced leaf manganese contents in both crops and leaf iron content in soybean. GY application improved the calcium status of both crops and the sulfur status of soybean. However, 70GY2 reduced leaf magnesium contents in soybean and wheat. Soil tillage without lime reduced wheat yield by 12% compared with no-till. Soybean yield correlated positively with leaf nitrogen (0.79), leaf phosphorus (0.91), leaf area (0.62), and thousand grain weight (0.65), whereas wheat yield correlated with leaf phosphorus (0.83), calcium (0.75), and sulfur (0.74). For improved soybean and wheat performance, it is preferable to apply lime and GY to the soil surface (70GY1), permanently maintaining no-till practices.

Biomass partitioning reveals the adaptability of tiger nut (Cyperus esculentus L.) in an arid ecosystem in Inner Mongolia, China

AbstractTiger nuts (Cyperus esculentus L.) have been widely cultivated as a bioenergy crop in northern China. The value of tubers is receiving special attention, but the lack of information on how organs of tiger nuts coordinate resources to adapt to arid environments has limited the potential tuber production and diverse use. To address this knowledge gap, we experimented in the Ulan Buh Desert, Inner Mongolia (106° 33′ 28″ E, 40° 27′ 32″ N). Three fertilizer treatments were applied: zero fertilizer (N:P = 0:0), traditional fertilizer (N:P = 15:15), and additional nitrogen fertilizer (N:P = 60:15). Investigations were conducted at seedling, rhizome production, tuber formation, and tuber maturation stages. The results showed that under zero fertilizer, tiger nuts allocated biomass predominantly to propagative organs, namely rhizomes and tubers. However, an increase in leaf area or root surface area would necessitate more investment in leaf or root dry mass, resulting in diminishing returns. For biomass allocation, tiger nut responded the same way to traditional fertilizer treatment and zero fertilizer treatment, but the tuber number and yield increase under traditional fertilizer application. Additional nitrogen fertilizer stimulated shoot production through accelerated rhizome production aided by leaf area increasing. Fertilizer application can significantly increase both the number of tiger nuts and tuber yield. Nitrogen addition positively influenced aboveground biomass and enhanced rhizome tillering. Strong adaptability of tiger nuts makes the plant a suitable pioneer crop for developing marginal lands. The robust aboveground growth after nitrogen application enhances suitability for pasture utilization.

Effect of bioaugmented Linz-Donawitz slag and biochar on physiological and yield attributes of wheat (Triticum aestivum)

Industrial wastes and agricultural by-products are increasingly used in crop production as supplements along with fertilizers. An experiment was conducted during the winter (rabi) seasons of 2021 and 2022 at the research farm of the ICAR-Indian Agricultural Research Institute, New Delhi to determine the individual and combined effects of bioaugmented Linz-Donawitz (LD) slag and biochar on physiological and yield attributes of wheat (Triticum aestivum L.) variety HD 2967. Bioaugmented products with cow-dung, LD slag and biochar in different combinations were prepared in laboratory scale and applied in crates. All the treatments were applied with 100%RDF except control. Growth parameters such as total leaf area, chlorophyll content, NDVI; and leaf photosynthetic attributes such as net photosynthetic rate, stomatal conductance and transpiration rate were affected by bio-augmentation. Our study reported an increase in total leaf area (18.2–21.3%), chlorophyll content (26.5–31.0%), net photosynthetic rate (93.2%), stomatal conductance (61.3%), transpiration rate (24.7%) in bioaugmented treatments with LD slag and biochar over 100%RDF. A yield increase of 25.6 and 27.1% was found in bioaugmented treatments with a combination of LD slag (2 t/ha) and biochar (1 t/ha) over 100%RDF during 2021 and 2022, respectively. No. of spikes, grains per spike and dry biomass weight were positively influenced by bioaugmentation. The bioaugmented treatments with a combination of LD slag and biochar gave significantly higher grain yield, followed by bioaugmented LD slag compared to bioaugmented biochar alone in the respective application rate of treatments.

Ammoniated straw returning: A win-win strategy for increasing crop production and soil carbon sequestration

Increasing crop production and soil carbon sequestration is critical for sustainable agricultural development. Straw returning, a common agricultural practice, positively affects grain yield and soil organic carbon. Nevertheless, the slow decomposition rate and high carbon-to-nitrogen ratio of straw are significant obstacles to its effectiveness. Ammonifying straw using urea and calcium hydroxide may be a promising solution, whereas limited information is available on the impacts of ammoniated straw returning on crop production and soil carbon sequestration. Therefore, in a winter wheat-summer maize rotation system, we conducted an experiment with three straw returning treatments (T1, straw removal; T2, traditional straw returning; T3, ammoniated straw returning) to investigate their impacts on crop growth, grain yield and yield components, carbon inputs and outputs, and net ecosystem carbon budget (NECB). The results showed that T3 outperformed T2 regarding increasing leaf area index and aboveground biomass. Ear density and thousand kernel weight of winter wheat and hundred kernel weight of summer maize were ranked T1 < T2 < T3, with no significant differences between treatments for other grain yield components. Consequently, winter wheat, summer maize, and annual grain yields were the highest under T3, followed by T2 and T1. In comparison with T1, T2 and T3 increased annual total carbon inputs by 5463 and 7271 kg C ha–1, respectively, due to the increased carbon inputs from returned straw and net primary productivity. Annual carbon total outputs, primarily from aboveground biomass removal at harvest and carbon respiration, increased by 3305 kg C ha–1 under T2 and 4264 kg C ha–1 under T3, compared with T1. Balancing annual total carbon inputs and outputs, T1, T2, and T3 had annual NECB values of –1215, 944, and 1793 kg C ha–1, respectively. Therefore, the T1 agroecosystem acted as a carbon source, whereas the T2 and T3 agroecosystems, particularly T3, acted as a carbon sink on an annual scale. These results suggest that ammoniated straw returning may be a superior straw application practice for increasing crop production and soil carbon sequestration simultaneously.

Water use and carbon assimilation respond differently to nitrogen supplementation in mid-rotation Eucalyptus nitens

ABSTRACT Large amounts of nitrogen (N) fertiliser are often applied to commercial plantations in southern Australia to obtain high growth rates. The growth response to fertiliser can be realised through increased foliar N and hence improved leaf-level photosynthetic capacity, or through increased leaf area production, which in turn increases light capture and hence canopy-level photosynthesis. While extra leaf area is beneficial to a tree in this regard, extra leaves may also incur costs in terms of both carbon (C) and water. Since canopy water use scales with total leaf area, greater leaf area could cause stomatal closure in times of water shortage, reducing the C assimilation rate. Here, we used three factorial N × phosphorus fertiliser experiments in Eucalyptus nitens plantations across Tasmania, Australia, to assess the effects of 12 fertiliser treatments on C- and water-related gas exchange, foliar N and trunk shrinkage. As prior research in this system has demonstrated an increase in leaf area in response to high N, we investigated the potential physiological costs and benefits of this extra leaf area. N application appeared to have consequences for plant water use, as evidenced by greater trunk shrinkage and lower stomatal conductance. However, this varied by site and year, indicating that the response is dependent on environmental conditions. These results highlight the importance of considering site conditions when prescribing fertiliser application regimes because adding large amounts of N could have unintended consequences for growth due to increased leaf area and hence potential water use, especially in dry conditions.

A Low Ratio of Red to Far-red Radiation (R:FR) Throughout the Photoperiod but Not at End-of-day Promotes Shade Avoidance for Petunia ×hybrida Seedlings

Electric lighting is often necessary to achieve a target daily light integral (DLI) for the production of high-quality young annual bedding plants (plugs). Early in production, plugs have a low leaf area index that limits light interception and likely results in wasted radiation supplied by electric sources. Previous research has shown that the addition of far-red radiation (700–780 nm) to the radiation spectrum in sole-source lighting experiments or the use of end-of-day far-red (EOD-FR) radiation treatments can promote an increase in leaf expansion and leaf area for many species. However, leaf expansion in response to far-red radiation may depend on other factors such as the ratio of red (600–699 nm) to far-red radiation (R:FR) and air temperature. Thus, the objectives of this work were to examine the effects of far-red radiation applied throughout the photoperiod and as an end-of-day radiation treatment on the morphology of petunia ‘Dreams Midnight’ seedlings grown under different temperature conditions. Specifically, petunia seed was sown in 128-cell trays and moved to one of two growth chambers set at 16 or 21 °C when cotyledons unfolded. Seedlings received an equal total photon flux density (400–780 nm) of 164 µmol·m−2·s−1 for a 17.25-hour photoperiod, and either a high (∼10.7) or low R:FR (0.5). Low R:FR-treated seedlings were grown at a constant temperature of either 16 or 21 °C and placed under blackout conditions at the end of the photoperiod. High R:FR-grown seedlings received either a 1-hour end-of-day white (EOD-W) or EOD-FR treatment at the end of the photoperiod, and were grown at a constant 16 or 21 °C; one EOD-FR treatment was also shifted from the 21 °C chamber to the 16 °C at the end of the photoperiod for both the EOD-FR treatment and subsequent dark period. Seedlings were harvested at 21 and 28 days after treatment initiation. For petunia seedlings grown at 21 °C, EOD-FR treatments had minimal effect on morphology or dry mass as all measured parameters, including total and average leaf area and stem length, were similar to EOD-W treatments. In contrast, low R:FR-treated seedlings showed responses characteristic of plants grown under shade, including significant stem elongation, an increase in total and average leaf area, and a reduction in leaf mass per unit area. As expected, production at 16 °C slowed the growth of petunia seedlings resulting in much smaller plants compared with the 21 °C grown plants, but shade responses such as elongated leaves and stems under a low R:FR were apparent. The EOD-FR–treated seedlings that received the diurnal temperature shift also showed reduced leaf area and dry mass compared with their constant 21 °C counterparts. Shade responses were observable at both 16 and 21 °C for low R:FR-grown plants, but the quantifiable impact of temperature on far-red responses could not be fully determined in the present study. Further research is warranted investigating crop responses to far-red radiation as well as potential interacting environmental factors as the promotion of morphological responses, such as leaf expansion, early in production may prove a useful strategy.

Dependence of far-red light on red and green light at increasing growth of lettuce.

Despite being outside of the traditionally defined photosynthetically active radiation (PAR) waveband (400-700 nm), far-red (FR; 700-799 nm) light can increase photosynthesis and induce shade-avoidance responses, which increases light interception and thus, whole-plant growth. However, it is unclear how the promotion of growth from FR light depends on PAR wavebands and specifically how the substitution of red light (600-699 nm) with green light (500-599 nm) influences the efficacy of FR light on increasing shoot biomass accumulation. To determine this, we grew red- and green-leaf lettuce (Lactuca sativa) at a fixed total photon flux density (PFD) with 12 different fractions of red, green, and FR light and the same PFD of blue (400-499 nm) light. We postulated that decreasing the red:FR by substituting FR light for green light, red light, or both would increase shoot fresh mass (FM) until a fraction beyond which growth (but not leaf area) would begin to decrease. Indeed, the substitution of red with FR light increased the leaf area of both cultivars, but FM was greatest under an FR fraction [FR/(R+FR)] of approximately 0.25. Under the greatest FR PFD, FM was similar to lettuce grown without FR light, despite having greater leaf surface area for light interception. Green light had less of an effect on leaf expansion and FM than FR light, and plant diameter and leaf area of red-leaf 'Rouxai' were the greatest when green light fully replaced red light at the highest FR PFD. We conclude that under a modest light intensity and blue PFD, a spectrum that includes up to 25% of far-red photons can increase leaf area and biomass accumulation. While leaf area may continue to increase at higher far-red fractions, fresh mass does not, and plant quality begins to deteriorate.

The effect of soil liming, nitrogen and potassium application on the growth, development and physiological parameters of Calendula officinalis L.

The effect of soil liming and the addition of different doses of nitrogen and potassium on the growth, development and operation of FAS pot marigold plants (Calendula officinalis L. abrikosovy jam variety was studied. Experimental options: option 1 (control); option 2 (lime 4.6 t/ha); option 3 (lime 4.6 t/ha, N70K140); option 4 (lime 4.6 t/ha, N100K200). The plants were grown at an illumination intensity of PAR 200 mmol/m2, with a photoperiod of 12 hours before the flowering stage. The results of the study showed that the application of lime and mineral fertilizers significantly increased the biomass, height, leaf area of plants and the intensity of photosynthesis, accelerated the development of plants compared with the control. At the same time, the greatest influence on plant productivity was exerted by the introduction of lime into the soil, which caused a maximum increase in the intensity of photosynthesis and the water use efficiency (WUE), an increase in the number of inflorescences and their mass. The addition of urea and potassium sulfate caused an additional increase in plant weight and leaf area. There was no significant effect of nitrogen and potassium addition on the chlorophyll content, stomatal conductance, transpiration intensity and WUE.

Nutrient availability and growth of bell pepper plants under fertilization management with humic substances and cattle manure.

Humic substances associated with cattle manure can enhance and reduce the costs of organic fertilization. In this sense, the objective was to evaluate the application of humic substances in association with cattle manure on soil fertility, growth and root nutrition in pepper plants. The experimental design used was randomized blocks, arranged in a factorial scheme with 4 doses of cattle manure (8, 18, 28 and 38 Mg ha-1), 3 doses of humic substances (0, 8 and 12 kg ha-1), with 4 replicates. The variables analyzed were plant height, stem diameter, leaf area, root growth, fresh and root dry weight, root macronutrient contents and soil fertility. Increases in plant height, leaf area and root dry matter (21.2, 58.21 and 8% respectively) were obtained by associating the application of humic substances with manure. Humic substances (12 kg ha-1) in association with manure (8 Mg ha-1) provided an increase in nitrogen content in the roots (36.05%) compared to the application of manure alone, and the application of humic substances (12 kg ha-1) promoted an increase of 10.62% in potassium content in the roots. The availability of calcium in the soil regulated primary root growth. The association of humic substances with cattle manure promoted shoot growth, root dry weight and root nutritional increase in pepper plants.

Effect of Late Cultivation under Low Tunnels on the Growth and Productivity of Some Leafy Vegetables

The experiment was carried out in 2022-2023, on agricultural land in Idlib governorate, in the West Northern of Syrie. Experimental treatments were planted under low tunnels and covered with transparent plastic, to study the effect of late planting of spinach and lettuce crops in protected conditions. The seeds of local varieties of spinach and lettuce were used for the research. The experiment was carried out according to a randomized complete block design. The experiment results indicated that using protected cultivation methods led to significantly better outcomes in various aspects compared to open-field cultivation. For both spinach and lettuce crops, protected cultivation resulted in higher seed germination percentage (1.3 times), increased leaf area of seedlings (3.3 times), more marketable plants (1.8 times), greater number of leaves per plant (1.3 times), taller plant height (1.3 times), higher seedling weight (3 times), and greater plant weight at harvest (1.5 times). Overall, the total productivity per unit area increased using protected cultivation. The average increase rate for all studied traits was 1.9 times higher in protected cultivation compared to open cultivation. As a result, we recommend late cultivation of spinach and lettuce crops under low tunnels to shorten the cultivation period after the completion of long-season summer cultivation.

Efeito da fertilização e inoculação com bactérias promotoras de crescimento no desenvolvimento da Poinsettia var. Prestige

Abstract Euphorbia pulcherrima is a plant with colorful bracts sold mainly at Christmas time, and is the most important ornamental container plant in the world. To produce healthy plants with high-quality standards, growers intensively apply pesticides and fertilizers, which increases production costs and promote environmental pollution. Plant growth-promoting rhizobacteria (PGPR) represent an environmentally friendly technological alternative for ornamental production. Therefore, this work evaluated the effect of three bacteria (Pseudomonas sp. CPO 2.78, Enterobacter sp. CPO 2.5, and Bacillus megaterium CPO 2.35) isolated from the rhizosphere of E. cyathophora on the vegetative and reproductive growth of E. pulcherrima var. Prestige Red in the presence of three doses of multipurpose Ultrasol fertilizer (0, 50% and 100%) after 236 days under greenhouse conditions. At vegetative stage (118 days), bacterial inoculation produced greater leaf area and higher leaf weight, total dry weight, and relative chlorophyll content, especially with the 50% fertilizer combination. At reproductive stage (236 days), inoculating a mixture of the three bacteria combined with 50% fertilizer increased leaf area, chlorophyll content, total dry weight, plant width, and number of branches. Overall, using PGPR plus 50% fertilizer improved growth and production of E. pulcherrima, and obtained a plant quality similar to that achieved without inoculation plus 100% fertilization.

The impact of biochar and arbuscular mycorrhizal inoculation on garden egg (Solanum gilo L.) performance

Abstract Garden eggs are an important vegetable, but often yield poorly due to soil fertility depletion. Biochar has gained interest in mitigating nutrient loss, while arbuscular mycorrhizal fungi (AMF) reportedly enhance plant nutrition. However, limited information exists on garden egg responses to biochar application and their interactions with mycorrhizal inoculation. Therefore, the effects of biochar and AMF inoculation on garden egg performance were investigated. In a 3 × 2 factorial field experiment during the 2021 and 2022 cropping seasons, biochar (0, 2.5, and 5 t/ha) and AMF inoculation (−AMF and +AMF) were evaluated in a randomised complete block design with three replicates. Garden egg (NHSg−3) seedlings were transplanted at 60 cm × 60 cm spacing. Data were subjected to ANOVA at p &lt; 0.05. Applying 5 t/ha biochar and AMF inoculation resulted in a significant leaf area increase compared with their respective controls. Fruit yield was significantly higher with 2.5 t/ha biochar than other treatments. The AMF-inoculated plants had significantly higher fruit yield (726.40 kg/ha) than the untreated plants (644.17 kg/ha). Fruit yield for biochar and AMF interactions ranged from 436.50 (− AMF) to 854.53 kg/ha (+AMF inoculation) at 5 t/ha biochar. However, 5 t/ha biochar resulted in significantly higher weed biomass and lower microbial count, while 2.5 t/ha biochar +AMF and −AMF treatments gave 771.63 and 802.08 kg/ha fruit yields, respectively, enhanced microbial counts, and reduced weed biomass. Applying 2.5 t/ha biochar without AMF inoculation was considered adequate for good garden egg performance and improved soil conditions.

Efecto del extracto de &lt;i&gt;Limnospira maxima &lt;/i&gt;sobre parámetros fisiológicos de Stevia &lt;i&gt;Stevia rebaudiana &lt;/i&gt;Bert. y berenjena &lt;i&gt;Solanum melongena &lt;/i&gt;L. bajo condiciones controladas

A strategy that could partially or totally reduce the use of chemical synthesis fertilizers is the application of cyanobacteria with agricultural potential that promote plant growth, which powers them in the conception of a sustainable agriculture. The study evaluated the effect of four concentrations of an extract of Limnospira maxima (0, 4, 8, and 12 mg mL-1), on some physiological aspects of Stevia rebaudiana and Solanum melongena in house vegetation. Treatments were arranged under a complete random design and parameters of gas exchange, chlorophyll a fluorescence, biometric characteristics and biomass distribution were measured. The most important results indicated that in Stevia rebaudiana and Solanum melongena the rates of net photosynthesis increased respectively by 40,03% and 22,45% when cyanobacteria was applied. On the other hand, plants of both species that were inoculated required less electrons to maximize their photosynthesis rates, increased leaf area, plant height and biomass distribution in roots and leaves. The most important physiological indicator was net photosynthesis and this was positively correlated with almost all the parameters studied. The results suggest that the use extracts of L. maxima may be a biotechnological alternative of organic fertilization useful for the development of sustainable agriculture.