Relative Growth Research Articles

Single and combined effects of metal-based fungicides on Eisenia andrei in different scenarios of climatic change.

This study evaluated the ecotoxicity of metal-based fungicides under the current scenarios of global climatic change (20°C and 25°C) and moisture content (30% and 50%) in single and binary mixtures of copper oxychloride (CuOx) [200, 500 and 1000mg/kg] and mancozeb (MnZn) [44, 850 and 1250mg/kg]. Endpoints assessed included mortality, changes in biomass, avoidance behaviour, and reproduction utilising standardised protocols (ISO and OECD). The changes in biomass and mortality tests lasted 28days, followed by a 28-day reproduction test and a two-day avoidance test. In all temperature-moisture combinations, the mortality rate in the exposure groups exceeded 10% only in the CuOx1000 and CuOx1000 + MnZn1250 mg/kg groups. However, at 20°C and 30% moisture, the mortality rate exceeded 10% only in the CuOx500 + MnZn850 mg/kg treatment. Relative growth rates in the CuOx and MnZn treatment groups decreased with increasing concentrations. In CuOx MnZn and the binary mixture treatments at 20°C 30% and 25°C 50% conditions, avoidance response behaviour was greater than 80% throughout the exposure, except in CuOx200 mg/kg, MnZn44 mg/kg and CuOx200 + MnZn44 mg/kg. The reproduction of exposed earthworms in all treatment groups was concentration-dependent and influenced by varying temperatures and soil moisture conditions. No juveniles or cocoons were produced in the CuOx1000 mg/kg treatment at 25°C 30%, indicating that copper oxychloride may be more toxic than mancozeb, especially in drought conditions. This study found that different temperatures and soil moisture levels altered the ecotoxicity of CuOx and MnZn. It can be concluded that climate change is likely to significantly impact the outcomes of metals to earthworms and their ecological activities.

Growth Rate and Nutrient Uptake of Stevia rebaudiana Bertoni as Influenced by Organic Manures in Laterite Soils of Kerala, India

A field experiment was conducted to understand the effect of organic manures on the crop growth rate (CGR), relative growth rate (RGR), and nutrient uptake of stevia (Stevia rebaudiana Bertoni) from April to August of 2022 and 2023 at the Agronomy farm, Department of Agronomy, College of Agriculture, Vellanikkara, Thrissur. The experiment was laid out in randomized block design (RBD) with 7 treatments replicated thrice which consisted of different levels of organic manures viz., three levels of farmyard manure (FYM@ 5, 10, 15 t ha­-1), three levels of vermicompost (VC@ 2.5, 5, 7.5 kg ha-1) and a control. The organic manure treatments significantly affected crop growth rate (CGR) and relative growth rate (RGR) in all the growth periods. The two-year pooled mean of CGR of stevia was significantly superior in FYM@15 t ha-1 over control in all the three growth periods i.e., at 0-30 DAP, 30-45 DAP and 45 DAP to harvest. Whereas, the two-year mean of RGR of stevia was found statistically higher in FYM@15 t ha-1 over control in the first two growth periods only. The organic manure treatments had a significant influence on the plant nutrient (NPK) uptake as well in both the years. The two-year pooled mean data regarding plant uptake of nitrogen and phosphorous was found significantly higher in FYM@15 t ha-1 over control whereas statistically higher pooled mean potassium uptake by stevia was found in VC@7.5 kg ha-1 over control. Overall, the higher levels of organic manure, especially FYM, significantly improve growth and nutrient uptake in stevia.

Modelling and optimizing secondary metabolites production in Spirodela polyrhiza using machine learning

Spirodela. polyrhiza as one of the potential feedstocks for industrial natural dye and pharmaceutical products, efficient process to produce from it were scarce. Here, Artificial Neural Network (ANN) and Genetic Algorithm (GA) were employed for modelling and optimization respectively. Current study focus on establishing useable models and anticipating the optimal concentration of nitrate (NO3−), phosphate (PO43−) and ammonium (NH4+) to give highest relative growth rate (RGR) and produce maximum amount of anthocyanins, chlorophylls, phenolic compounds and antioxidants. In short, 12 and 11 neurons in hidden layer were found to be most suitable neuron numbers used for the modelling of growth and secondary metabolites respectively. All the models exhibited a high degree of robustness and performance with a high r2 value (higher than 0.75) and a low mean squared error (lower than 0.05). GA also anticipated the best concentration of macronutrients to achieve the maximum growth and metabolites production with significant low errors (below 7 %). The employment of machine learning was useful for such applications.

Influence of Cow Dung Extract Complemented with Nutrient Solution on the Growth Performance of Lettuce (Lactuca sativa L)

Limited studies have focused on plant growth performance using organic-based solutions complemented with mineral elements in a hydroponic system. Thus, this study aimed to investigate the growth performance of lettuce (Lactuca sativa L.) as influenced by cow dung extract combined with a hydroponic nutrient solution. Treatments considered as four different levels of aerated cow dung extracts (C), viz., C1 = 50 g l-1, C2 =100 g l-1, C3 =150 g l-1 and C4 =200 g l-1 and four strengths of standard nutrient solution (S), viz, S1 = 30% of standard nutrient solution, S2 = 40% of standard nutrient solution, S3 = 50% of standard nutrient solution and S4 = 60% of standard nutrient solution. The experiment was carried out using a deep flow technique in a semi-greenhouse. Various growth and physiological parameters were measured in this experiment. The obtained data were subjected to statistical analysis with 4 replicates by analysis of variance (ANOVA) using SPSS. In the case of growth parameters, the tallest plant (23.54 cm), maximum number of leaves per plant (17.01) broadest leaf (13.32 cm), and the highest fresh weight (112.05 g/plant) were recorded from C3 while the lowest in C1. For hydroponic nutrient solution, the tallest plant (23.13 cm), the maximum number of leaves per plant (16.66), the widest leaf breath (14.17 cm), and the highest fresh weight (116.0 g/plant) were recorded from S4 while the lowest in S1. On the other hand, physiological traits viz. leaf area, net assimilation ratio, and relative growth rate were statistically higher in C3 and lowest in C1. In the nutrient solution, all physiological parameters were highest in S4 and the lowest in S1. In the case of the interaction effect, the highest fresh weight and almost all the parameters were found best in C3S4 and the lowest in C1S1. Therefore, the analysis showed that in terms of growth promotion properties hydroponic nutrient solution along with cow dung extract had a substantial impact and C3S4 was the most preferable treatment combination. Based on these findings, in a hydroponic system, an inorganic nutrient solution combined with organic liquid fertilizer derived from cow dung extract (as an alternative nutrient source) requires further improvements to achieve optimal growth and yield.

Enhanced competitiveness of Spirodela polyrhiza in co-culture with Salvinia natans under combined exposure to polystyrene nanoplastics and polychlorinated biphenyls

Micro- and nanoplastics (MNPs) and polychlorinated biphenyls (PCBs) are prevalent in the environment and pose potential threats to ecosystems. However, studies on the phytotoxicity of MNPs and PCBs on primary producers are limited. This study investigated the effects of polystyrene nanoplastics (PS-NPs, 10 mg/L) and 2,2′,5,5′-tetrachlorobiphenyl (PCB-52, 0.1 mg/L), on the growth of Spirodela polyrhiza and Salvinia natans, and their impact on plant competitive ability under co-culture conditions. Laser confocal microscopy images revealed that PS-NPs accumulated on the leaf and root surfaces of both species. Combined exposure to PS-NPs and PCB-52 significantly inhibited the average specific and relative growth rates (RGR) of both species, reduced chlorophyll a and b levels, and slightly increased carotenoid content, disrupting the photosynthetic system. PCB-52 exacerbated PS-NPs accumulation on plants, leading to increased hydrogen peroxide (H2O2) and superoxide anion (O2−) production in both roots and leaves. This affects the activity of superoxide dismutase (SOD), peroxidase (POD), malondialdehyde (MDA), and the soluble protein content. The combined treatment with PS-NPs and PCB-52 induced greater ecological stress in both species than the treatment with PS-NPs alone. In addition, the combined treatment with PS-NPs and PCB-52 significantly improved the relative yield and competition balance index of S. polyrhiza, indicating that PS-NPs + PCB-52 enhanced the competitive ability of S. polyrhiza when co-cultured with S. natans. This study confirmed the effects of co-exposure to PS-NPs and PCB-52 on aquatic plant growth and species competition, contributing to better insight into the ecological impacts of MNPs and organic pollutants.

Plant stoichiometry in relation to relative growth rate

Abstract Plants need certain proportions between elements for proper growth and functioning. These proportions vary with growth conditions and it has generally been found that with increasing relative growth rates P:N should increase (the growth rate hypothesis). However, proportions between N and other elements change with growth rates and how this determines which element is limiting growth is not well studied but it is possible that limitations of other elements could restrain plant growth more than N. Using results from nine studies with birch plants (Betula pendula) with different limiting elements (N, P, K, S, Mg, Zn, Mn, Fe, and Cu) under steady state growth, I have investigated how the switch, defined as the ideal proportion, between which element is limiting growth varies with relative growth rate. The ideal proportion of element:N increases with increasing relative growth rate for K,P, Zn, and Mn but a slight decline for Mgand S The changes in element:N ratios are strongest at low relative growth rates. Consequences of these results for plant properties under global change are discussed.

Effect of Organic and Inorganic Sources of Nitrogen on Growth, Yield, Quality and Soil Properties of Wheat (Triticum aestivum L.)

Background: The concept of combined use of both organic and inorganic fertilizer should be followed to prevent severe health hazards and to protect the environment. The combined use of organic and inorganic fertilizers is an effective way to maintain nutrient supply, gives organic carbon to soil microbes and mobilizes soil-bound nutrients on decomposition through the release of organic acid. Combined use refers to combining all available nutrient sources, such as organic and inorganic sources with components in a prudent manner to create an environment that is both environmentally sound and economically ideal for farming. Methods: The experiment was conducted at the research farm of the School of Agriculture, Department of Agronomy, Lovely Professional University, Phagwara (Punjab) during rabi season in the year 2021-2022. The objective of the study was to evaluate the "Effect of organic and inorganic source of nitrogen on growth and yield of wheat (Triticum aestivum L.)". Data recorded on different aspects of crop, viz., growth, yield attributes, yield, quality as well as soil chemical properties were recorded and subjected to statistical analysis. Result: Among various treatments 25% RDN with vermicompost + 75% RDN from inorganic fertilizers showed a significant impact on the growth and yield parameters of wheat crop. Significantly higher growth parameters viz., plant height, number of tillers m-2, dry matter and relative growth rate were observed in T12 (25% RDN with vermicompost + 75% RDN from inorganic fertilizers) of crop. It was also showed higher significant impact on yield attributes i.e., number of effective tillers-2, grain yield, straw yield, harvest index, quality parameters as well as soil parameter like available nitrogen, phosphorus and potassium in T12 (25% RDN with vermicompost + 75% RDN from inorganic fertilizers).

Colonialism, Weaponisation of Ethnicity & Intermittent Political Violence

Ethnic conflicts have increased across the globe, and especially after the Cold war; and indeed affected various countries in Europe, Africa, Asia and America. In most of these cases, it has been triggered by struggles for the meagre resources and domination of political power. In Africa, studies on ethnic conflicts have indicated a strong interplay between ethnicity and the colonial phenomenon. This article endeavours to connect the intermittent political violence in Uasin Gishu, Kenya, within the purview of the colonial phenomenon particularly, when the violence was viewed historically as a process and not an event. It hypothesizes that the violent subterfuge of ethnic communities in Uasin Gishu and other portions of the rift valley were the result of the despair and fear perceived by native communities as a result of presumed economic and political setbacks during the colonial era. To this end, the initial research study was guided by three theories, namely: Primordialism, instrumentalism and relative deprivation theories which reinforced each other as the lens through which to make sense of the connection between colonialism and the said intermittent political violence. The study is based on a research project that employed the historical method from the dual perspectives of interpretivism philosophical outlook and qualitative approach. The main submission, in this research article, is that the coming and settlement of the colonialists led to the growth of toxic ethnic relations within the Rift valley region that were initially non-existent. This situation was further exacerbated after independence (1963), as the political elites became the new drivers of the vice

Physiological and biomolecular interventions in the bio-decolorization of Methylene blue dye by Salvinia molesta D. Mitch

Methylene blue, a cationic dye as a pollutant is discharged from industrial effluent into aquatic bodies. The dye is biomagnified through the food chain and is detrimental to the sustainability of aquatic flora. Despite of number of physico-chemical techniques of dye removal, the use of aquatic flora for bio-adsorption is encouraged. Thus, we used Salvinia molesta D. Mitch in bio-reduction of methylene blue on concentrations of 0, 10, 20, and 30 mg L−1 through 5 days with biosorption kinetics. The dye removal was concentration-dependent, maximized at 2 days with 30 mg L−1 which altered the relative growth rate (44%) of plants. Biosorption recorded 71% capacity at optimum pH (8.0), 24 h reducing major bond energies of amide, hydroxyl groups, etc. Bioaccumulation of dye changed potassium content (446%) under maximum dye concentration modifying tissues for dye sequestration. Reactive oxygen species were altered on dye reduction by oxidase (33%) with redox homeostasis by enzymes. Plants altered the metabolism with over accumulation of polyamines (51%), abscisic acids (448%), and phosphoenolpyruvate carboxylase (83%) on dye reduction. Thus, this study is rationalized with a sustainable approach where aquatic ecosystems can be decontaminated from dye toxicity with the exercise of bioresources like Salvinia molesta D. Mitch as herein.

Effects of seeding methods and nutrient management practices on growth and yield of organic wheat (Triticum aestivum)

An experiment was conducted out during winter (rabi) seasons of 2021–22 and 2022–23 at the Research Farm of Maharana Pratap Univesity of Agriculture and Technology, Udaipur, Rajasthan to study the effect of nutrient management practices and sowing methods on the development and production of organic wheat (Triticum aestivum L.). The experiment was conducted in a split plot design (SPD) with 4 replications. The experiment consisted of 3 sowing methods in main plots, viz. Flat row sowing; FIRB (Furrow Irrigated Raised Bed) sowing; and zero tillage sowing and 8 nutrient management practices, viz. 100% RDN through FYM as basal; RDN through FYM as basal + 50% RDN with first irrigation; 75% RDN through FYM as basal + 25% RDN with first irrigation; 50% RDN through FYM as basal + 25% RDN with first irrigation + 25% RDN with second irrigation; 100% RDN through FYM as basal + jeevamrit @500 litre/ha at sowing and first irrigation + panchagavya @5% at booting stage; 50% RDN through FYM as basal + 50% RDN with first irrigation + jeevamrit @500 litre/ha at sowing and first irrigation + panchagavya @5% at booting stage; 75% RDN through FYM as basal + 25% RDN with first irrigation + jeevamrit @500 litre/ha at sowing and first irrigation + panchagavya @5% at booting stage; 50% RDN through FYM as basal + 25% RDN with first irrigation + 25% RDN with second irrigation + jeevamrit @500 litre/ha at sowing and first irrigation + panchagavya @5% at booting stage in sub plots. The experimental results revealed that the FIRB sowing method recorded significantly higher plant height at 45 DAS (42.56 and 42.66 cm) during both the years of study over zero tillage sowing method and remain at par with flat row sowing method, respectively. The same sowing method resulted into statistically higher grain yield (42.88 and 43.87 q/ha) and biological yield (106.89 and 108.48 q/ha) compared to flat row sowing and zero tillage sowing methods during both the years, respectively. During the second year of study (2023) significantly highest crop growth rate (CGR) (1.1240 g/m2/day) and relative growth rate (RGR) (0.0083 g/g/day) between 90 DAS to harvest were recorded with flat row sowing over zero tillage sowing and remain at par with FIRB sowing method. Regarding the nutrient management practices the highest plant height (43.43 and 44.51 cm), grain yield (44.52 and 44.84 q/ha) and biological yield (110.35 and 110.58 q/ha) were recorded with 75% RDN through FYM as basal + 25% RDN with first irrigation + jeevamrit @500 litre/ha at sowing and first irrigation + panchagavya @5% at booting stage.

Feeding and Growth Response of Fall Armyworm Spodoptera frugiperda (Lepidoptera: Noctuidae) towards Different Host Plants.

The fall armyworm, Spodoptera frugiperda, is a major migratory polyphagous insect pest of various crops. The essential nutrient and mineral profile of the host plants determines the feeding fitness of herbivorous insects. As a result, the growth and development of insects is affected. To determine the effect of the nutrient and mineral profile of different host plants (maize, castor bean, cotton, cabbage, okra, and sugarcane) on the growth and development of S. frugiperda, biological parameters like larval weight, pupal weight (male/female), and feeding and growth indices were calculated. The proximate compositions such as crude protein, crude fat, crude fibre, and ash and mineral contents of the tested host plants showed significant differences (p < 0.05). The feeding indices on these host plants also differed significantly (p < 0.05). The maximum relative growth rate (RGR), relative consumption rate (RCR), and consumption index (CI) were recorded in S. frugiperda larvae that fed on maize and castor bean leaves. The crude protein, dry matter, and ash contents in maize and castor bean were significantly higher and positively correlated with the RGR and RCR of S. frugiperda larvae. The larval, male and female pupal weights were the maximum in the larvae feeding on the castor bean host plant. These findings provide novel information based on nutritional ecology to develop sustainable integrated pest management strategies using selective crop rotation.

Eco-tech fusion: Unraveling the nonparametric causal effects of fintech, natural resources, digital infrastructure, and economic growth on environmental sustainability from a quantile perspective

Environmental sustainability has the potential to uphold an ecological balance in the natural environment. Unfortunately, it is challenging due to the environment's multifaceted nature and the complex interlinkages of environment with social, economic, and technology-related factors. The current study inspects the causal effect of fintech, natural resource rent, digital infrastructure, and economic growth in relation to environmental sustainability. This study comprises the time frame of 2002–2022 in the BRICS nations. The "nonparametric causality-in quantiles approach" has been applied, which is an advanced econometric tool. The results confirm that all BRICS countries, i.e., Brazil, Russia, India, China, and South Africa, show a significant causal impact of the said predictors on sustainable environment in most cases. This study is significant for scholars, investors, policymakers, manufacturers, and environmental regulatory bodies.

Effects of Root Pruning and Size on Growth Traits of Hybrid Poplar Seedlings

Selecting seedlings of varying sizes and effectively managing root pruning are key challenges in transplantation. However, the effects of seedling size and root pruning on transplantation outcomes are not fully understood. This study classified one-year-old Populus ‘Beilinxiongzhu-01’ seedlings into three size categories based on height: large (308.75 ± 9.66 cm), medium (238.00 ± 7.71 cm), and small (138.92 ± 7.18 cm). In early March of the subsequent year, root pruning was applied with varying intensities based on root collar diameter: low (15 times), medium (7.5 times), and high (3.75 times). A control group without pruning was also included. Over the year, key phenological and morphological traits were monitored. The results showed that (1) root pruning significantly impacted the phenology of seedlings, accelerating root emergence, delaying early leaf phenology, increasing the dieback rate, and postponing end-of-season defoliation. Mortality and the rapid growth phase were not significantly affected. Larger seedlings exhibited earlier end-of-season defoliation and higher dieback rates early in the growing season, while smaller seedlings advanced in early leaf development. (2) Except under low or no pruning, root pruning reduced seedling height (H), diameter at breast height (DBH), and root collar diameter (RCD). However, across all treatments, these indicators remained higher in larger seedlings compared to smaller ones. Under medium- and high-intensity pruning, smaller seedlings exhibited higher relative growth rates and larger leaf areas than larger seedlings, with the reduction in these variables becoming more pronounced as seedlings increased in size. Notably, only larger seedlings demonstrated a reduction in maximum growth rate, suggesting greater vulnerability to root pruning. In summary, root pruning induced significant phenological and morphological differences across seedling sizes. While smaller seedlings showed some response to pruning, larger seedlings experienced more pronounced phenological disruptions and growth inhibition.

Sodium alginate-g-polyacrylamide hydrogel for water retention and plant growth promotion in water-deficient soils

Natural polymer-based hydrogels are preferred as soil water retention agents due to their inherent biocompatibility and biodegradability. Generally, these natural polymers are chemically modified by graft polymerization of vinyl monomers to improve their water absorption and retention properties. Among the polysaccharides used to prepare natural hydrogels, those based on sodium alginate (Alg) stand out for their high-water absorption and retention capacity, as well as for their ability to promote plant growth. The main objective of this study was to develop a biodegradable alginate-based hydrogel as a water retainer to promote plant growth under water deficit conditions. The synthesis was achieved by grafting poly(acrylamide) (PAM) onto Alg backbone, using bisacrylamide as chemical crosslinker and different ratios of alginate:acrylamide (Ac). In addition, Eucalyptus nitens seedlings were used as a model plant to evaluate the effect of alginate-g-polyacrylamide (Alg:PAM) hydrogel application to the growing medium on plant survival, growth, and physiological responses under both well-watered and water-deficient soil conditions. The maximum degree of swelling (65 g/g) was obtained for the hydrogel prepared. The pseudo-second order model described the water uptake kinetics of the hydrogel. The degradability of Alg:PAM hydrogel reached up to 85 % in 5 weeks in soil and occurs by breaking the glycosidic bonds of the alginate. The E. nitens seedlings cultivated with different doses of Alg:PAM hydrogel (4:1 Alg:Ac) showed higher values of height and root diameter relative growth, survival and photosynthetic responses in comparison to non-treated plants. The results indicate that Alg:PAM hydrogel (4:1 Alg:Ac) has promising applications in forestry as a water retention and seedling growth promoter under water deficient conditions.

Response of Types of Cuttings and IBA Concentration from First Sprout to Highest Sprouting and Rooting in Crossandra (Crossandra infundibuliformis L.)

The present investigation was conducted under Konkan Agro-climatic conditions at College of Horticulture, Dr. Balasaheb Sawant Konkan Krishi Vidyapeeth, Dapoli, Dist. Ratnagiri (India) during the kharif season (2023-2024). The experiment was laid out in Factorial Randomized Block Design (FRBD) with twelve treatment combinations and three replications. Present investigation found that in types of stem cuttings treatment C1 :Softwood cuttings was found best with respect to minimum days to first sprout, days to highest sprouting , maximum number of new sprouts/cuttings, girth of sprout, length of new sprout, number of leaves, leaf area, survival(%), fresh weight of shoot, dry weight of shoot, absolute growth rate, relative growth rate, number of roots, length of longest root, fresh weight of root, dry weight of root, shoot to root ratio. In different IBA concentration treatment H4 : IBA@2000ppm was found best with respect to minimum days to first sprout, days to highest sprouting , maximum number of new sprouts/cuttings, girth of sprout, length of new sprout, number of leaves, leaf area, survival(%), fresh weight of shoot, dry weight of shoot, absolute growth rate, relative growth rate, number of roots, length of longest root, fresh weight of root, dry weight of root. In interaction effect treatment C1H4 (Softwood cuttings treated with IBA@2000 ppm) is found to be most effective among all other treatment combinations in terms of most of the parameters such as Sprouting percentage, Number of new sprouts/cuttings, Length of sprout/cuttings, Girth of new sprout, Number of leaves/cuttings, Leaf area, Survival percentage, Fresh weight of shoot, Relative Growth Rate, Fresh weight to dry weight of shoot ratio, Number of roots.

Dietary effect of turmeric and ginger powder supplementation on growth performance of Common carp (Cyprinus carpio)

A study was conducted with the aim to find out the effect of ginger and turmeric supplementation on the growth performance of Common carp fingerlings. A total of 270 fingerlings were divided into 6 groups including control (C). The group C was fed with basal feed and the treatment groups T5, T5B5, G2, G5, G8 were fed with turmeric powder @0.5%, turmeric @0.5% + black pepper powder @0.5 %, ginger powder @2%, 5% and 8%, respectively. The growth parameters, i.e Gain in weight, Feed Conversion Ratio (FCR), Specific Growth Rate (SGR), Relative Growth Ratio (RGR), Protein Efficiency Ratio (PER) and Feed Efficiency Ratio (FER) were recorded for 60 days. Measurements were taken for gain in total length (TL) and body depth (BD) after 60 days of trial. Turmeric powder supplementation @0.5% showed significantly better growth performance in Common carp fingerlings. The fingerlings of T5 group showed highest gain in weight (48.7), SGR (1.35), RGR (126), FER (48.17), PER (1.24) and improved FCR (2.23). This group also gained significantly higher TL (3.74) and BD (1.42). There was no significant difference observed in survival per cent, moisture and acid insoluble ash content of fish muscle. T5 showed the highest crude protein concentration (78.29) and significantly highest total fat concentration (11.59). Fish muscles of all the treatments had significantly higher total mineral content as compared to that of the control group.

Toxicity of Nitrite to Juvenile Sunray Surf Clam (Mactra chinensis Philippi)

Nitrite is a common pollutant in marine environments and can cause mortality in crustaceans and bivalves. The purpose of the current study is to understand nitrate’s toxicity to juvenile clams due to its potential impact on aquaculture and marine ecosystems. Juvenile sunray surf clams (Mactra chinensis Philippi) (1.00 ± 0.10 cm shell length, 0.75 ± 0.04 cm shell height) were exposed to varying concentrations of nitrite for 96 h and 20 days, respectively. The LC50 for survival at 96 h was 37 mg/L NO2-N. Histological evaluations were made on juvenile clams exposed at 30 mg/L after 20 d of exposure. Epithelial cells and digestive diverticulum are the best sub-lethal effect indicators. Shell length and antioxidant enzyme activities were measured at the beginning of the experiment and then observed 10 and 20 days after exposure. A logarithmic relationship was obtained between the relative growth rate (based on the shell length) of juvenile M. chinensis and the nitrite concentration. Compared to the control, activity suppression of superoxide dismutase and catalase activity was detected from the concentration of 1 mg/L NO2-N. It is recommended that nitrite concentrations remain below 1 mg/L to prevent stress during the early developmental stages of clams.

Growth, Morphology and Respiratory Cost Responses to Salinity in the Mangrove Plant Rhizophora Stylosa Depend on Growth Temperature.

Mangrove plants, which have evolved to inhabit tidal flats, may adjust their physiological and morphological traits to optimize their growth in saline habitats. Furthermore, the confined distribution of mangroves within warm regions suggests that warm temperature is advantageous to their growth in saline environments. We analyzed growth, morphology and respiratory responses to moderate salinity and temperature in a mangrove species, Rhizophora stylosa. The growth of R. stylosa was accelerated in moderate salinity compared with its growth in fresh water. Under warm conditions, the increased growth is accompanied by increased specific leaf area (SLA) and specific root length. Low temperature resulted in a low relative growth rate due to a low leaf area ratio and small SLA, regardless of salinity. Salinity lowered the ratio of the amounts of alternative oxidase to cytochrome c oxidase in the mitochondrial respiratory chain in leaves. Salinity enhanced the leaf respiration rate for maintenance, but under warm conditions this enhancement was compensated by a low leaf respiration rate for growth. In contrast, salinity enhanced overall leaf respiration rates at low temperature. Our results indicate that under moderate saline conditions R. stylosa leaves require warm temperatures to grow with a high rate of resource acquisition without enhancing respiratory cost.

Small cyst size and lack of growth as negative predictors of malignant transformation in low-risk intraductal papillary mucinous neoplasms of the pancreas: A systematic review and meta-analysis.

For branch-duct intraductal papillary mucinous neoplasms (BD-IPMNs) without worrisome features (WFs) or high-risk stigmata (HRS), current guidelines recommend surveillance. However, these intraductal papillary mucinous neoplasm (IPMNs), especially the small and stable-sized ones, carry a low risk of malignant transformation. Our aim was to assess whether small cyst size and absence of rapid growth provide reassurance against the development of WFs/HRS and malignancy (high-grade dysplasia (HGD) or pancreatic cancer (PC)). PubMed/Medline, Embase, the Cochrane Library and the Web of Science Core Collection were systematically searched from inception to May 2023 to identify studies investigating surveillance outcomes of low-risk BD-IPMNs. Studies assessing baseline cyst size and/or growth in relation to WFs/HRS and/or HGD/PC were included. The Newcastle-Ottawa scale tool was used to assess study quality. Of the 1937 identified manuscripts, 21 studies were eligible for inclusion. The quality of these studies was considered reasonable. A negative association between cyst size and WFs/HRS development was found in 11 out of 13 relevant studies, but only one out of nine studies reported a negative association between size and malignancy. Regarding cyst growth, four out of six studies described a negative association with the development of WFs/HRS, and all six reported a negative association with malignancy. The pooled relative risk (RR) of developing WFs/HRS or malignancy for cysts ≤15mm was 0.37 (95% CI 0.25-0.57) and the RR of developing malignancy for cyst growth <2-2.5mm/year was 0.04 (95% CI 0.02-0.09)). This systematic review and meta-analysis shows that small and stable-sized low-risk BD-IPMNs are associated with a markedly low progression rate, with stable cyst size being the most reassuring feature. Because of substantial heterogeneity in definitions and reported outcome measures, prospective studies are needed to confirm that surveillance of small and stable sized cyst can be de-intensified or even discontinued.

Two Western Pacific Tabernaemontana Species Contrast in Biomass Allocation and Leaf Physiological Plasticity to Sun and Shade

The ability of plants to modify biomass allocation and leaf phenotypes to best utilize available resources has been heavily studied. No Tabernaemontana species have been included in this research agenda. Therefore, Tabernaemontana pandacaqui Poir. and Tabernaemontana rotensis (Kaneh.) B.C. Stone plants were subjected to 24% or 100% sunlight and various traits were determined to compare the relative level of plasticity. Midday net carbon dioxide assimilation was greater for T. rotensis in sun-grown plants, but greater for T. pandacaqui in shade-grown plants. Saturating light intensity and midday Fv/Fm were greater for T. rotensis in sun-grown plants, but did not differ between the species for shade-grown plants. Light compensation intensity was greater for T. rotensis than T. pandacaqui in both light treatments. Apparent quantum yield was greater for T. pandacaqui shade-grown plants but was similar for the two species in sun-grown plants. Greater relative root growth in full sun compared with shade was exhibited by T. rotensis but not by T. pandacaqui. These findings indicated that T. pandacaqui develops functional traits that improve performance in shade-grown plants, and T. rotensis develops facultative traits that enable performance in sun-grown plants. These insights into how T. pandacaqui and T. rotensis respond to sun and shade conditions add to the knowledge needed to inform the selection of niche conditions when using them in managed mixed forest plantings such as conservation and restoration sites.