Reduced Leaf Area Research Articles

Exploring the Role of Calcium in the Physiology of Tulipa: A Comparative Study across Different Cultivars

Cut tulip flower production, typically cultivated using hydroponic systems, often faces the challenge of stem toppling due to calcium (Ca) deficiency in the nutrient solution. Growers generally grow various tulip cultivars to meet market demands. In hydroponic production, plants require precise nutrient concentrations to promote growth and development, as the food reserves in the mother bulb are insufficient and vary depending on the plant cultivar. This study aimed to assess the impact of different tulip cultivars and Ca deficiency on tulip growth, flowering, and physiological changes. Two cultivars of tulip, namely, ‘Strong Gold’ and ‘Orange Juice’, were subjected to three distinct nutrient solution treatments, namely (1) deionized water (DI) only (without any plant nutrition added), (2) complete solution (Hoagland’s complete nutrient solution), and (3) Ca deficiency solution. The results indicate that the ‘Orange Juice’ tulip was particularly susceptible to Ca deficiency, exhibiting stem toppling and flower abortion similar to those grown in DI. Ca deficiency led to a reduction in root length and leaf area but did not affect the plant height. Additionally, it had a negative impact on bulb qualities, resulting in a decreased bulb fresh weight and bulb circumference in both tulip cultivars. Furthermore, Ca deficiency and DI reduced the photosynthetic rates, and Ca deficiency increased the transpiration rate in the tulip. The leaf concentrations of nitrogen (N), phosphorus (P), and Ca were decreased under Ca deficiency and DI, while magnesium (Mg) levels increased under Ca deficiency treatment compared to the complete nutrient solution treatment.

Detrimental Effects of Lithium on in vitro Seedlings of Pea (Vigna radiata)

The global demand for lithium-ion batteries has raised concerns about environmental consequences stemming from lithium leaching. In this study, we investigated the effects of lithium, sourced from Li2SO4, on in vitro seed germination and seedling growth of green moong (Vigna radiata). Our experiments used woody plant medium supplemented with 1 mg/l naphthalene acetic acid (NAA) and 2 mg/l benzyl adenine (BA). We observed that in vitro seed germination remained unaffected by lithium concentration. However, at concentrations of 3-5 mg/l of lithium, significant changes were observed in stem parameters including growth reduction, shoot tip damage and stem discolouration. Root growth was inhibited at lithium concentrations of 4 and 5 mg/l. Additionally, we noted leaf abscission, dark colouration and reduced leaf area in a dose-dependent manner. Necrotic lesions were not observed in the seedlings. Chlorophyll accumulation, phenolic content and peroxidase (POD) activity showed enhancement with increasing lithium concentration. Our data analysis strongly suggests dose-dependent toxicity in young seedlings under in vitro conditions. These findings shed light on the potential ecological implications of lithium leaching from retired batteries.

Subsoiling before winter wheat alleviates the kernel position effect of densely grown summer maize by delaying post-silking root-shoot senescence

Intensified kernel position effect is a common phenomenon in maize production under higher plant density, which limits the crop productivity. Subsoiling is considered as an effective agronomic practice to improve crop productivity. In order to clarify the effect of subsoiling before winter wheat on kernel position effect of densely grown summer maize and its regulatory mechanism, field experiments were conducted during 2020-2021 and 2021-2022 growing seasons by using a split-plot design. Main plot include two tillage practices: conventional tillage practice (CT) and subsoiling before winter wheat (SS); subplot consist three plant densities (D1-D3, 6.0×104, 7.5×104, and D3, 9.0×104 plants ha-1). Compared with CT, SS alleviated the kernel position effect by increasing the weight ratio of inferior to superior kernel (WR) of D2 and D3 treated plants. The higher WR of SS treated plants attribute largely to the improved filling of inferior kernel. Under the same plant density, SS significantly improved the root dry matter accumulation (DMA) and antioxidant enzyme activities (SOD and POD), and reduced malondialdehyde (MDA) concentration, especially for the plants grown under higher plant densities. These result indicated that SS delayed the root senescence, which is associated with the reduced soil bulk density. In addition, by comparison with CT, SS increased the leaf chlorophyll content from 20 days after silking to physiological maturity and post-silking leaf area duration, and decreased post-silking leaf chlorophyll reduction rate and leaf area reduction rate, reflecting the post-silking leaf senescence is alleviated. Under the same plant density, the post-silking DMA of SS was obviously higher than that of CT, which is probably related to the improved leaf area duration and photosynthetic enzyme activity (PEPC and Rubisco). The correlation analysis revealed that the main mechanism of SS in alleviating kernel position effect of densely grown summer maize is: SS delayed the post-silking root-shoot senescence by regulating soil physical properties, and further improved the post-silking DMA and filling of inferior kernel, ultimately alleviated the kernel position effect and improved grain yield. The present result will provide a new theoretical support for the promotion of summer maize yield by subsoiling before winter wheat.

Leaf area reduction during the pod set period changes the photomorphogenic light balance and increases the pod number and yield in soybean canopies

Leaf area reduction during the pod set period changes the photomorphogenic light balance and increases the pod number and yield in soybean canopies

Effect of water stress and foliar application of chitosan and glycine betaine on lettuce

The present study investigated the effect of foliar application of chitosan at 150 ppm and glycine betaine at 700 ppm on lettuce plants cv. Balady grown under well-watered and water deficit conditions in terms of growth, yield, quality, and water usage efficiency. The study was conducted in Qalubia Governorate, Egypt, during the two seasons of 2020/2021 and 2021/2022 on clay soil. Results indicated that water-stressed plants had a reduction in plant fresh weight, plant height, leaf area, and total yield, chlorophyll content and relative water content, while they exhibited an increase in total soluble solids, nitrate, and proline contents as well as water-use efficiency in both seasons. The foliar application of chitosan or glycine betaine to lettuce significantly improved plant performance under limited and normal irrigation conditions in comparison with untreated plants. The maximum positive effect was for chitosan foliar application. Overall, the results of this study indicated that foliar application of chitosan or glycine betaine was a substitute technology for improving the lettuce yield and quality as well as increasing water use efficiency under both irrigation regimes, but may be more efficient in lettuce plants subjected to a water deficit.

Biological and Chemical Characterization of Musa paradisiaca Leachate.

There is a growing demand for molecules of natural origin for biocontrol and biostimulation, given the current trend away from synthetic chemical products. Leachates extracted from plantain stems were obtained after biodegradation of the plant material. To characterize the leachate, quantitative determinations of nitrogen, carbon, phosphorus, and cations (K+, Ca2+, Mg2+, Na+), Q2/4, Q2/6, and Q4/6 absorbance ratios, and metabolomic analysis were carried out. The potential role of plantain leachates as fungicide, elicitor of plant defense, and/or plant biostimulant was evaluated by agar well diffusion method, phenotypic, molecular, and imaging approaches. The plant extracts induced a slight inhibition of fungal growth of an aggressive strain of Colletotrichum gloeosporioides, which causes anthracnose. Organic compounds such as cinnamic, ellagic, quinic, and fulvic acids and indole alkaloid such as ellipticine, along with some minerals such as potassium, calcium, and phosphorus, may be responsible for the inhibition of fungal growth. In addition, jasmonic, benzoic, and salicylic acids, which are known to play a role in plant defense and as biostimulants in tomato, were detected in leachate extract. Indeed, foliar application of banana leachate induced overexpression of LOXD, PPOD, and Worky70-80 genes, which are involved in phenylpropanoid metabolism, jasmonic acid biosynthesis, and salicylic acid metabolism, respectively. Leachate also activated root growth in tomato seedlings. However, the main impact of the leachate was observed on mature plants, where it caused a reduction in leaf area and fresh weight, the remodeling of stem cell wall glycopolymers, and an increase in the expression of proline dehydrogenase.

Diagrammatic scale for the quantification of black spot severity in papaya leaves

Black spot (Asperisporium caricae) is one of the main foliar fungal diseases of papaya crops. This disease acts directly on leaves and fruits causing leaf area reduction and fruit deterioration. The quantification of diseases is a fundamental part of the disease management and control process; therefore, a scale is required to help quantify black spot disease. The objective of this work was to propose a standardized methodology to quantify black spot severity in papaya leaves. A scale was developed considering the maximum and minimum values of the disease in the field that included eight levels of severity: 0.1, 0.3, 0.6, 1.0, 2.3, 5.0, 10.0, and 20.0%. Without the aid of a scale the disease is often overestimated, with absolute errors of approximately 75%. When the scale was used, 100% of the evaluators showed improved accuracy and precision, and absolute error was reduced to the 10% range. The scale also provided good repeatability and high reproducibility. The use of the scale provided an improvement in the R2 values, with mean values of 93 and 92 in the second and third evaluations, respectively, demonstrating that the scale is useful for different aspects of the pathosystem of A. caricae, such as for determining the efficiency of fungicides, characterization of varietal resistance, construction of the disease progression curve, and estimation of damage.

Salinity and sodicity stresses differentially influence growth and physiology in sapota (Achras zapota L.)

Salt stress adversely affects the growth and physiological relations in most tree fruit species. Little is known about genetic variation for salt tolerance, and the physiological mechanisms underlying salt tolerance in sapota (Achras zapota), an underutilized fruit crop valued for its nutritive and medicinal properties. Here, we examined the effects of saline (ECiw 4, 8, 12, and 16 dS/m) and sodic (RSC 2.5 and 5.0meq/l) water treatments on plant growth, physiology, and ion homeostasis in the different genotypes of Sapota. Although saline and sodic treatments appreciably reduced the plant growth (i.e., by 20–50%) compared to salt-free plants, genotypes ‘CSRS-13’ and ‘CSRS-15’ performed better than others. Salt-induced reductions in leaf area were indicative of the ability of sapota to better acclimatize to prolonged salinity stress by regulating the biomass production. Saline and sodic irrigation treatments increased the leaf Na+ and decreased the leaf K+; albeit with clear-cut genotypic differences. We observed better ion homeostasis in genotype ‘CSRS-17’ under salinity stress, and better physiological adaptations in genotypes ‘CSRS-11’ and ‘CSRS-17’ under sodicity stress. Principal Component Analysis revealed strikingly different responses of sapota genotypes to ‘low’ and ‘high’ salinity/sodicity treatments. Strong cultivar-specific responses to salinity and sodicity stresses evinced the existence of genetic variation for salt tolerance in sapota. Overall, our findings demonstrated the feasibility of sapota cultivation in areas with moderate sodicity (RSC ∼2.5 meq/l), and moderate-to-high salinity (∼8.0 dS/m).

Plants lacking OST1 show conditional stomatal closure and wildtype-like growth sensitivity at high VPD.

Climate change-associated rise in VPD (atmospheric vapor pressure deficit) results in increased plant transpiration and reduced stomatal conductance, photosynthesis, biomass, and yield. High VPD-induced stomatal closure of Arabidopsis is an active process regulated via the kinase SnRK2.6 (OPEN STOMATA 1, OST1). Here, we performed gas exchange, leaf water potential and rosette growth measurements to study, whether (1) high VPD-induced stomatal closure is detected in plants carrying loss-of-function mutations in OST1 (ost1-3) when they are grown at reduced soil water content or measured at increased air temperature; (2) ost1-3 plants expressing OST1 construct with no ABA-activation domain, but intact ABA-independent activation, show stronger stomatal VPD response compared with ost1-3 plants; and (3) rosette area and biomass of ost1-3 are more affected by growth at high VPD compared with Col-0. The stomata of well-watered ost1-3 plants were insensitive to high VPD regardless of air temperature, but in deficit-irrigated ost1-3, leaf water potential decreased the most and stomata closed at high VPD. Differences between VPD-induced stomatal closures of ost1-3 plants and ost1-3 plants expressing OST1 with no ABA-activation domain point at gradual VPD-induced ABA-independent activation of OST1. High VPD conditions led to similar reductions in rosette area and specific leaf area of well-watered Col-0 and ost1-3 plants. Rosette dry mass was unaffected by high VPD. Our results show that OST1 loss-of-function plants display conditional stomatal closure and no extra sensitivity of rosette area growth compared with Col-0 wildtype under high VPD conditions.

Effects of target tree management on understory regeneration in Pinus massoniana plantations.

To clarify the effects of target tree management on natural forest regeneration, with Pinus massoniana plantations in the low mountainous regions of eastern Sichuan with target tree densities of 100, 150 and 200 trees·hm-2 as test object, we analyzed the effects of management densities on canopy structure, plant diversity, and soil physicochemical properties on understory regeneration. The results showed that the regeneration index increased with management density, which increased 0.08-0.10 in the managed plantations compared with unmanaged sites. When the density of the target trees was 150 trees·hm-2, an increase of 9 regeneration tree species and an increase of 800 trees·hm-2 in quantity were observed. The dominance of herbaceous species was not prominent, but canopy structure was improved, and the regeneration ability of understory plants was enhanced. The impact of habitat factors on the regeneration index ranked as soil total porosity (0.591) > leaf area index (-0.536) > Shannon index (-0.085) > available P (0.053) > total N (-0.007) > Pielou index (-0.005). Target tree management facilitated understory regeneration in the P. massoniana plantations by improving soil pore conditions, reducing leaf area index, and decreasing herbaceous plant diversity index. A management density of 150 trees·hm-2 was more sui-table for target tree management in P. massoniana plantations.

Mini-cutting as a technique to propagate Tabebuia aurea, an important tree found in tropical dry forests

Tabebuia aurea is a hardwood species from Brazil. This species yields high-quality wood for diverse applications and has a high value in phytosociological importance, but little has been done regarding an effective propagation method for large-scale production in nurseries. Alternatively, vegetative propagation techniques such as mini-cutting technology (an evolution of the cuttings technique) can be used, which has the potential to facilitate mini-stumps (stock plants), productive capacity, and vigour of the propagules (mini-cuttings). Therefore, this paper aimed to establish a protocol for vegetative propagation using the mini-cutting technique for Tabebuia aurea. For this, four independent experiments were conducted: the first evaluated the survival and production of mini-stumps between four harvests; the second tested the interaction between mini-cutting types (apical and intermediate) and different concentrations of indole-3-butyric acid (IBA; 0, 2.000, 4.000, and 6.000 mg.L-1) on adventitious rooting; the third analysed the effect of leaf area reduction (0%, 50%, 75%, and 100%) on mini-cuttings; and the fourth verified the substrate effect (100% coconut fibre, 50% coconut fibre + 50% commercial organic compost, and 100% commercial organic compost) on mini-cuttings rooting. The survival; percentage of rooted mini-cuttings; number of roots; length of the largest root; aerial dry mass; and root system dry mass were measured as response variables. The results indicated that all mini-stumps survived four harvests, remained productive, and produced propagules responsive to adventitious rooting. Rooting and mini-cutting survival rates were high, up to 80% without IBA, and the maximum mean setting value of 90% for apical mini-cuttings in the IBA concentration of 2000 mg.L-1 and 4000 mg.L-1 to intermediate mini-cuttings. Treatments without leaf reduction and with a reduction of 50% promoted better results concerning rooting and plant development. The substrate influences adventitious rooting; coconut fibre + organic compost (1:1) are indicated for the species propagation. For the highest system productivity, apical mini-cuttings with 2000 mg.L-1 of IBA, no leaf reduction, and coconut fibre + organic compost (1:1) are recommended as substrates

Salicylic acid-mitigates abiotic stress tolerance via altering defense mechanisms in Brassica napus (L.).

Under the changing climate due to global warming, various abiotic stresses including drought (D) and salinity (S) are expected to further trigger their devastating effects on the already vulnerable crop production systems. This experiment was designed to unravel and quantify the potential role of exogenous application of salicylic acid (SA) in mitigating both D and S stresses and their combination (D+S), with three replications using CRD (Completely Randomized Design). The obtained results of the current study demonstrated significant effects of all three types of stresses (D, S, and D+S) on various parameters in Brassica napus plants. Quantifying these parameters provides a more informative and precise understanding of the findings. Current results revealed that all three stress types (D, S, and D+S) resulted in a reduction in leaf area (13.65 to 21.87%), chlorophyll levels (30 to 50%), gaseous exchange rate (30 to 54%) and the concentration of mineral ions compared to non-stressed plants. However, application of SA helped in mitigating these stresses by ameliorating the negative effects of these stresses. Moreover, Malondialdehyde (MDA) contents, an indicator of lipid per-oxidation and oxidative stress, the levels of antioxidants, proline content, an osmolyte associated with stress tolerance, and sugar content in the leaves were elevated in response to all stress conditions. In addition, the ultra-structures within the leaves were negatively affected by the stresses, while an application of SA considerably minimized the deterioration of these structures thus providing protection to the brassica plants against the stresses. In a nutshell, the findings of this study suggest that SA application in S, D and S+ D stresses provides evasion to the plants by improving different physiological and growth indices. The application of Salicylic Acid (SA) mitigated the negative effects of the stresses on all the above parameters, reducing MDA contents (47%), antioxidants (11 to 20%), proline (28%), sugar contents (20.50%), and minimizing the deterioration of ultra-structures. The findings emphasize the potential mitigatory role of SA in mitigating D and S stresses and highlight the need for further research to understand the underlying mechanisms in detail and explore its practical application in farming practices.

Investigating the phytotoxic potential of Carlina acaulis essential oil against the weed Bidens pilosa through a physiological and metabolomic approach

Essential oils (EOs) are widely studied as possible candidates for new eco-friendly herbicides for weed management due to their phytotoxicity. In this study we tested the phytotoxic potential of the EO obtained from the roots of Carlina acaulis L. (Apiaceae) against the weed Bidens pilosa L. This EO, containing 98% of the polyacetylene carlina oxide, showed strong phytotoxic effects on the plant metabolism, such as leaf necrosis, reduction of relative water content and total leaf area, and an increase in the dry weight/fresh weight ratio, suggesting a water status alteration. The EO also damaged the photosynthetic machinery, as evidenced by the significant reduction of the effective quantum yield of photosystem II (ΦII) and the maximum quantum yield of photosystem II (Fv/Fm). In addition, the non-photochemical quenching (ΦNPQ) significantly increased after spraying with C. acaulis EO. Damage to photosystem II was further demonstrated through the reduction of manganese and calcium concentrations, possibly due to an alteration in the correct functionality of the Mn4Ca cluster of the PSII. Metabolomics analysis revealed an accumulation of branched-chain amino acids, such as isoleucine and valine, which is commonly related to osmotic alterations under drought stress situations and a general reduction in sugar content (fructose, glucose, mannose, among others), suggesting reduction of the photosynthetic efficiency too. Overall, these findings suggest C. acaulis EO as a promising natural product with phytotoxic potential against weeds that deserves further investigation.

Seed Treatment with Sodium Nitroprusside Ensures a Long-Term Physiological and Protective Effect on Wheat under Salinity.

Although salinity inhibits plant growth, the use of a nitric oxide (NO) gasotransmitter can reduce its negative effects. In this study, the influence of 200 μM sodium nitroprusside (SNP) (donor of NO) on wheat plants (Triticum aestivum L., cv. Salavat Yulaev) in conditions of salinization (100 mM NaCl) was analyzed in pot experiments. Seed priming regulated the level of endogenous NO in normal and salinity conditions throughout the entire experiment (30 and 60 days). Salinity led to the strong accumulation of NO and H2O2, which is negative for plants, and significantly reduced leaf area and photosynthetic pigments (chlorophyll a and b and carotenoids). In addition, stress caused a drop in the content of reduced glutathione (GSH) and ascorbic acid (ASA), an accumulation of oxidized glutathione (GSSG), and significantly activated glutathione reductase (GR), ascorbate peroxidase (APX), and lipid peroxidation (LPO) in wheat leaves. SNP treatment significantly attenuated the negative effects of salinity on leaf area and photosynthetic pigments. An important indicator of reducing the damaging effect of salinity on treated plants is the stabilization of the content of GSH and ASA throughout the experiment (60 days). This condition has been associated with long-term modulation of GR and APX activity. Such an effect of 200 μM SNP may be related to its ability to reduce stress-induced accumulation of NO. Additional accumulation of proline also mitigated the negative effect of salinity on plants, and this also evidenced decreased LPO and H2O2 in them. For the first time, in natural growing conditions (small-scale field experiments), it was found that pre-sowing seed treatment with 200 μM SNP led to an improvement in the main yield indicators and an increase in the content of essential amino acids in wheat grains. Thus, SNP treatment can be used as an effective approach for prolonged protection of wheat plants under salinity and to improve grain yield and its quality.

Effects of Hemlock Woolly Adelgid Control Using Imidacloprid on Leaf-Level Physiology of Eastern Hemlock

Widespread mortality of eastern hemlock (Tsuga canadensis [L.] Carr.) has been occurring due to the introduction of hemlock woolly adelgid (Adelges tsugae Annand) (HWA), threatening millions of hectares of hemlock-dominated forests in the eastern United States. HWA feeds at the base of needles and removes stored carbohydrates, which can impact leaf-level physiology, contributing to the decline of the tree. However, these physiological mechanisms in HWA-infested hemlocks are still not clearly understood. We investigated hemlock leaf physiology year-round at three forested sites with various degrees of infestation. At each site, half the trees were treated with imidacloprid (Merit® 2 F, Bayer, Kansas City, MO, USA) while the rest were left untreated. Imidacloprid is widely used to control HWA but can itself have phytotoxic effects. After one growing season, there was an increase in photosynthetic rates (7.5%, p = 0.0163) and stomatal conductance (7.1%, p = 0.0163) across sites in the trees treated with imidacloprid. After two years, the imidacloprid treatment also increased bud break from 22.5% to 88.7% at Fishburn (the most severely impacted site) and from 22.7% to 58.9% at Mountain Lake (the least impacted site), and slightly increased chlorophyll fluorescence for treated trees at Fishburn. Chemical treatment also slightly increased water use efficiency at Mountain Lake. These results suggest that HWA is causing tree mortality largely through a reduction in leaf area caused by decreasing bud break and also by a slight, but significant, reduction in leaf-level photosynthesis and stomatal conductance.

Safety profile evaluation of different herbicides used on peach rootstock seedlings.

To screen out suitable herbicides for peach nurseries, we treated the potted seedlings of the peach rootstock 'Nemaguard' with eleven herbicides under recommended doses to investigate the changes of physiological indices and comprehensively evaluate the safety of different herbicides using principal component analysis (PCA). The results showed that soil application of quizalofop-p exhibited no detectable phytotoxicity on rootstock seedlings, while the remaining herbicides generated multiple symptoms, including green loss, wilting, spot, and withering. Starane caused rapid wilting and death, with a 100.0% phytotoxicity index (PI). Soil application of n-(phosphonomethyl)glycine, glufosinate-ammonium, acetochlor, and MCPA-Na showed a PI＞65.0%. As compared with the control, all herbicides inhibited leaf area growth to varying degrees, with a 10.0%-56.2% and 5.8%-44.4% reduction in young leaf area and mature leaf area, respectively. All herbicides, except quizalofop-p, increased the electrolyte permeability of leaf and root tip cells by 21.2%-145.0% and 36.9%-291.4%, respectively, and significantly inhibited root growth. The total root length, root surface area, root volume, and the number of root tips significantly decreased by 37.3%-75.3%, 35.7%-83.0%, 44.3%-89.9%, and 42.6%-73.7%, respectively. Although net photosynthetic rate (Pn) and transpiration rate (Tr) of leaves were not significantly affected by quizalofop-p, mesotrione-atrazine, MCPA-Na·bentazone, bensulfuron-methyl·quinclorac, and bensulfuron-methyl·acetochlor, there was significant reduction of 29.6%, 28.9%, 28.4% and 27.9% in Pn and 21.9%, 29.2%, 26.4%, and 19.7% in Tr post soil application of n-(phosphonomethyl)glycine, glufosinate-ammonium, acetochlor, and MCPA-Na. The overall safety ranking of the 11 examined herbicides is as follows: quizalofop-p>bensulfuron-methyl·acetochlor>bensulfuron-methyl·quinclorac>esotrione·atrazine> auizalofop-p·fluoroglycofen>acetochlor>MCPA-Na·bentazone>MCPA-Na>n-(phosphonomethyl)glycine>glufosinate-ammonium>sterane.

Waterlogging stress reduces cowpea (Vigna unguiculata L.) genotypes growth, seed yield, and quality at different growth stages: Implications for developing tolerant cultivars under field conditions

Waterlogging is a significant abiotic stress that reduces the oxygen supply to roots in the rhizosphere, impairing plant growth and development. Cowpea is highly sensitive to waterlogging, and their grain yield is affected by genotype and growth stage. Understanding the growth and physiological responses of cowpea to waterlogging stress is crucial for developing strategies to improve crop yield in waterlogged environments. In this two-year field trial, we quantified the impact of ten days of waterlogging on morpho-physiological attributes, seed yield components, and seed quality of two cowpea genotypes (UCR 369 and EpicSelect.4) at different growth stages. Waterlogging during the reproductive (R2) growth stage had the most substantial impact on cowpea, with an average reduction of leaf area by 65%, chlorophyll content by 39%, stomatal conductance (gs) by 93%, and photochemical efficiency by 32% compared to non-waterlogged plants. These effects were less pronounced during the vegetative (V4) and physiological maturity (R7) growth stages. Lower photosynthetic capacity resulted in reduction of biomass accumulation, pod dry weight, number of pods per plant, and seed weight under waterlogging. EpicSelect.4 was more sensitive to waterlogging at the R2 stage, showing a greater reduction in seed yield (58%) compared to UCR 369 (46%). Additionally, UCR 369 maintained seed protein content under waterlogging conditions, while it decreased by 8% in EpicSelect.4 seeds. Overall, UCR 369 was more tolerant to waterlogging stress than EpicSelect.4, with the most apparent effect of waterlogging on yields occurring at the R2 stage due to the high energy demands of the cowpea reproductive process. Our study highlights the importance of selecting cowpea genotypes with greater tolerance to waterlogging stress during the reproductive stage to mitigate the negative effects of waterlogging on seed yield in flood-prone environments. These results provide valuable insights into the mechanisms of cowpea's responses to waterlogging stress and can aid in developing strategies for improving cowpea yield in waterlogged environments, which are expected to become more frequent due to climate change.

Prevalence and Severity of Sigatoka Disease of Banana in Cameroon

Sigatoka Disease (SD) represents the major pre-harvest fungal disease of banana and also appear as the major constraint of banana production. This diseaseis caused by two major pathogenic fungi, Pseudocercospora fijiensis and P. musicola. It provokes necrotic lesions on leaves and serious infestations leads to a substantial reduction in the green leaf area of infected plants and thus the photosynthetic area of the plant and consequently leads to yield loss. In the present work, three plantations were surveyed and experiments conducted in Southwest Cameroon to assess the prevalence and severity of sigatoaka disease in the banana plantations. Our results revealed a 100 % prevalence of Sigatoka in the field with an incidence of 59 %. In a severe manner, the severity in all the plantations was seen to have a constant increase with the highest severity at 23.83 % observed in plantation 1. In a nutshell, the incidence and severity of the disease was seen to increase with respect to time and season.

The effect of thinning intensity on sap flow and growth of Norway spruce

Forest thinning can be used as an adaptive measure to improve the growth and resistance of Norway spruce forests affected by climate change. The impact of different thinning intensities on sap flow, growth, and tree water deficit of 40-year-old Norway spruce was tested. High thinning intensity (–61% of basal area) resulted in increased tree-level sap flow compared to the control (+27%), but it caused a decrease in the stand-level transpiration (–34%) due to reduced leaf area index. Low-intensity thinning (–28% basal area), high-intensity thinning, and control showed similar responses of sap flow to vapour pressure deficit and global radiation, suggesting unchanged isohydric behaviour. Both low- and high-intensity treatments displayed greater radial growth than the control. There were no differences in tree water deficit between the treatments. The low-intensity treatment can be considered the best water utilisation treatment with increased growth and unchanged transpiration at the tree level. The high-intensity treatment had similar radial growth as the low-intensity but lower stand-level transpiration, implying improved soil water availability. The study expands the ecophysiological understanding of thinning as a valuable silvicultural practice for adapting forest management of Norway spruce to the effects of climate change.

An Interesting Relationship between the Insecticidal Potential of Simarouba sp. in the Biology of Diamondback Moth

Alternative methods of insect management are an important field of study for agriculture. The current study aimed to determine the effect of aqueous extracts from Simarouba sp. (AE-S) on the biology of Plutella xylostella and to determine the toxicity of the extract to the nematode Caenorhabditis elegans (an important in vivo alternative assay system for toxicological study). Lyophilized AE-S was chemically investigated by Ultrahigh-performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS). We evaluated the effect of the botanical extract on the life cycle of P. xylostella, from larval stage to adult stage, at concentrations of 10%, 5%, 1%, 0.1%, 0.05%, and 0.01% and a control. Subsequently, we analyzed the toxicity of the extract in an in vivo model. AE-S showed high amount of phenolic and flavonoid compounds. Six compounds were identified based on UHPLC-MS/MS analysis, including flavanone, kaempferol, 4,5-dimethoxycanthin-6-one, 11-acetylamarolide, ailanthinone, and glaucarubinone. The median lethal time for P. xylostella was estimated to be 96 h in all concentrations of AE-S, and at 120 h, 100% of the individuals were dead. Larvae exposed to AE-S at concentrations of 0.01, 0.05, and 0.1% showed a reduction in leaf area consumption, underdevelopment, and reductions in movement and pupal biomass. The lowest concentrations of AE-S (0.1%, 0.05%, and 0.01%) did not cause mortality in nematodes. Thus, the aqueous extract of Simarouba sp. could be an effective control tool because it mainly acts in the larval stage, the stage at which the insect causes damage to brassicaceae.