Biomass Gain Rate Research Articles

Chemical composition and influence of essential oil from Croton pulegiodorus Baill. leaves on the nutrition and survival of Sitophilus zeamais Mots. (Coleptera: Dryophthoridae) as well as survival and behavior of Nasutitermes corniger Mots. (Blattodea: Termitidae)

Essential oils have been studied to develop sustainable alternatives for controlling pest-species. This study determined the chemical composition and toxicity of an essential oil from Croton pulegiodorus leaves against Sitophilus zeamais and Nasutitermes corniger. Ascaridole (22.75%) and camphor (18.11%) were the major compounds. The essential oil showed toxicity upon ingestion on S. zeamais, with LC50 and LC90 of 24.24 and 46.76 μL/g for 15 days, respectively. It presented a moderate (10.0 and 12.5 μL/g) to strong (15 μL/g) deterrent effect, interfering with nutritional parameters, causing a reduction in the relative consumption rate, relative biomass gain rate and efficiency in conversion of ingested food. Furthermore, it stimulated in vitro S. zeamais β-D-xylanase (+33.39%), endoglucanase (+8.28%), exoglucanase (+84.77%), and α-amylase (+359.18%) activities and reduced in vitro the activity of trypsin-like enzymes (-79.67%). The essential oil showed fumigant effect against N. corniger termites with LC50 and LC90 (24 h) of 0.57 and 3.26 μL/mL of air for workers and 1.63 and 4.74 μL/mL of air for soldiers respectively. In workers, it caused 100% mortality through contact in 2.08 and 0.49 min (at 0.4 μL/μL and neat oil). A significant increase in the number of self-cleaning and falls indicated behavioral changes induced by the oil in N. corniger workers. The study shows the potential of the essential oil of C. pulegiodorus leaves as an alternative method in the management of maize weevil and N. corniger.

A closed-loop approach for enhanced biodiesel recovery from rapeseed biodiesel-based byproducts through integrated glycerol recycling by black soldier fly larvae

The present study evaluated an innovative zero-waste approach for efficient recycling of byproducts from rapeseed-based biodiesel industry including lipid-free rapeseed cake (RSC) and waste glycerol by black soldier fly larvae (BSFL). RSC showed high organic matter and protein contents of 92.7 dw% and 32.1 dw%, respectively. Therefore, it was utilized as the main feed source for BSFL rearing, while waste glycerol was supplemented at different concentrations (0–10%, w/w). Application of 5.0% waste glycerol significantly enhanced larval biomass gain rate and areal productivity by 13.0% and 17.2%, respectively, over the control. Interestingly, lipid content also increased by 25.9% over the control. The study suggested a synergistic action in the mixture, where RSC is digested to achieve the growth and development, while waste glycerol can be integrated directly into fatty acid biosynthesis pathway to accumulate lipids. In addition to being a carbon source, morphological examination and FTIR analysis showed that waste glycerol has the potential to penetrate RSC biomass fibers easing its decomposition. Overall, the highest recorded fatty acid methyl esters (FAMEs) productivity of 98.0 mg m−2 was recorded in BSFL treated with 5.0% waste glycerol, which represented 57.7% higher than the control. Comparing to rapeseed biodiesel, saturated fatty acids proportion in the BSFL-based FAMEs at all studied treatments was much higher, leading to 11.9–12.9% higher cetane number. In conclusion, findings of this study provide new insights to BSFL as a promising mini-livestock for biodiesel production through innovative recirculation route of biodiesel byproducts towards waste reduction and sustainable development.

Seasonally dry tropical forest temporal patterns are marked by floristic stability and structural changes

ABSTRACT Background: Seasonally Dry Tropical Forests (SDTF) are recognized by their great biological diversity, but little is known about their temporal patterns, which may be crucial in a changing world. Here we aimed to characterize the SDTF dynamic patterns in floristic and structural changes, and also to evaluate shifts in dynamic rates and structural attributes such as richness, number of trees and biomass. Our hypothesis is that SDTF tree communities have their dynamic characterized by temporal fluctuations related to an instability pattern, in according to the already found for others tropical forests. For this we used a data of 42 400 m² plots in three fragments in the Brazilian Arboreal Caatinga, measured in 2005, 2010 and 2015. We evaluated temporal changes in richness, species composition, trees density, biomass and rates of tree mortality and recruitment; and also rates of biomass gain and loss. Results: We found a pattern of floristic composition stability, but with changes in structure and dynamics. There was a tree density decrease driven by constant mortality and by recruitment decrease, and biomass increase due to decrease in biomass loss and to increase in biomass gain. The biomass increase was main related to a small set of dominant species that are the most representative in the community dynamics. Conclusion: SDTF dynamics are related to stability in species composition, but with structural changes towards higher biomass stocks. The results are main related to community dynamics and to SDTF attributes such as climatic seasonality that drives the local ecological processes.

Evaluation of the insecticidal activity of Moringa oleifera seed extract and lectin (WSMoL) against Sitophilus zeamais

The maize weevil Sitophilus zeamais is a pest of remarkable economic importance as it attacks stored grains, processed cereals, and industrial foods. In this study, a water extract (WE) from Moringa oleifera seeds and water-soluble lectin (WSMoL) isolated from it were investigated for insecticidal activity against S. zeamais adults. The insects were maintained for 10 days on plates containing an artificial diet composed of wheat flour supplemented with WE (60.0–640.0 mg/g) or WSMoL (0.5–60 mg/g). Mortality rate, insect biomass, and amount of food consumed were recorded. The effects of WE and WSMoL on trypsin-like, α-amylase, and endoglucanase activities from insect guts were also investigated. Phytochemical analysis revealed the presence of flavonoids, tannins, saponins, phenylpropanoids, alkaloids, and reducing sugars in the WE. Furthermore, the presence of rutin and ellagic acid was confirmed by HPLC. The extract was toxic to S. zeamais (LC50: 214.6 mg/g) while WSMoL caused slight mortality (12.0 ± 2.7%) at the highest tested dose (60 mg/g). The intake of WE exerted moderate to strong deterrent effects. Moreover, WSMoL decreased the relative biomass gain rate and efficiency in the conversion of ingested food but did not exert deterrent action. The WE stimulated α-amylase and endoglucanase activities, while WSMoL stimulated trypsin-like activity from S. zeamais gut. In conclusion, the WE was toxic to S. zeamais probably due to its feeding-deterrent activity, while WSMoL did not cause acute mortality but negatively affected the nutritional physiology of the insects, which can have long-term impacts.

Accumulation of selenium in a Chinese cabbage of a grade Pak-choi in the course of cultivation

Most agricultural areas of Russia have soils poor in mineral selenium, causing higher oncology risks for population of such areas. The way to control malignancy incidence is selenium fortification of soils and plants. This can be achieved by agrochemical enrichment of cultivated plants with nutritive substrates containing essential minerals and trace elements. The current study aimed to assay the effect of inorganic selenium on the rate of Chinese pakchoi cabbage biomass gain for the development of agrochemical techniques for introducing selenium. The optimal selenium introduction technique would demonstrate the best balance of biomass gain rate and selenium ion accumulation in organic matter. Selenium ion accumulation dynamic was assessed during controlled growth of plants in soils enriched with nutritive substrate containing inorganic selenium (potassium selenite). The amount of selenium in plants was determined by spectroscopy. Mathematical functions describing the selenium uptake dynamic of controlled grown plants have been found, including derivatives of these functions that led to obtaining the numerical values of the respective uptake rates. It has been found that agricultural techniques that involve introduction of selenium at intermediate and late stages of cultivation are optimal for plant growth dynamic, as introducing selenium at early stages of cultivation has a negative impact on biomass uptake rates. Additionally, introducing potassium selenite to the nutritive substrate at 1.0 mg×dm–3 proved to be more effective than introducing potassium selenite at 0.5 mg×dm–3 as the former dosage led to a better plant growth dynamic.

Evaluation of the toxicity of essential oil from Alpinia purpurata inflorescences to Sitophilus zeamais (maize weevil)

The maize weevil, Sitophilus zeamais Motsch. (Coleoptera: Curculionidae), is a cosmopolitan pest that causes extensive and irrecoverable damage to storage grains. This work investigated the chemical composition, insecticidal activity, feeding-deterrent and repellent effects of an essential oil from Alpinia purpurata inflorescences against S. zeamais. Analysis by gas chromatography coupled to mass spectrometry (GC–MS) revealed the presence of 30 volatile constituents (mainly mono- and sesqui-terpenes). The main compounds found in the oil were β-pinene, α-pinene, trans-caryophyllene, camphene, and 7-epi-α-selinene. When ingested by S. zeamais adults, the A. purpurata oil did not kill the insects but disrupted their nutritional status since biomass gain rate and efficiency in conversion of ingested food were both negative or near zero. A weak feeding-deterrent effect was also detected. No toxicity was observed when the oil was applied directly on the cuticle of S. zeamais adults. The fumigant toxicity assay revealed that the A. purpurata oil killed S. zeamais adults with LC50 = 41.4 μL/L in air; however, no repellent property was detected. The essential oil from A. purpurata inflorescences was toxic to S. zeamais adults by fumigation and due to interferences in digestion of food. Fumigant toxicity is likely due to the presence of some monoterpene hydrocarbons and oxygenated monoterpenes.

Leaf nitrogen productivity is the major factor behind the growth reduction induced by long-term salt stress

Plant growth response to salinity on a scale of years has not been studied in terms of growth analysis. To gain insights into this topic, 2-year-old Mediterranean Fan Palm (Chamaerops humilis L.) and Mexican Fan Palm (Washingtonia robusta H. Wendl) seedlings, each with its own distinct plant morphology, were grown for 2 years in a peat soil and irrigated with water of 2 dS m(-1) (control) or 8 dS m(-1) (saline). Plants were harvested on seven occasions and the time trends in relative growth rate (RGR, the rate of increase of biomass per unit of biomass already existing) and its components were analysed. In the long term, salinity produced a slight reduction in the mean RGR, values in both species. In the short term, salinity caused a reduction in RGR. However, during the second year, plants irrigated with 8 dS m(-1) grew somewhat more quickly than the control plants, probably as a result of delay in the growth kinetics due to salinity. Regarding RGR components, leaf nitrogen productivity (the rate of biomass gain per unit leaf N and time) was the major factor causing the differences in RGR resulting from salinity. Washingtonia robusta showed a relatively high plasticity in plant morphology by increasing root and decreasing stem biomass allocation in the presence of salinity. However, the long-term response of W. robusta to salinity, based to a great extent, on this morphological plasticity, was less effective than that of C. humilis, which is based mainly on the contribution of leaf N to RGR values.

Feasibility of vermicomposting in biostabilization of sludge from a distillery industry

The feasibility of vermicomposting technology to stabilize the distillery industry sludge mixed with a bulking agent (cow dung) in different proportions viz. 20% (T 1), 40% (T 2), 60% (T 3) and 80% (T 4), was tested using composting earthworm Perionyx excavatus for 90 days. The vermitreated sludge was evaluated for different physico-chemical parameters and all vermibeds expressed a significant decrease in pH (10.5–19.5%) organic C contents (12.8–27.2%), and an increase in total N (128.8–151.9%), available P (19.5–78.3%) as well as exchangeable K (95.4–182.5%), Ca (45.9–115.6%), and Mg contents (13.2–58.6%). Data suggested that inoculated earthworms could maximize the decomposition and mineralization rate, if sludge is used with appropriate bulking material for earthworm feed. Vermicomposting also caused significant reduction in total concentration of metals: Zn (15.1–39.6%), Fe (5.2–29.8%), Mn (2.6–36.5%) and Cu (8.6–39.6%) in sludge. Bioconcentration factors (BCFs) for metals in different treatments were also calculated and the greater values of BCFs indicate the capability of earthworms to accumulate a considerable amount of metals in their tissues from substrate. The reproduction biology of P. excavatus in different treatments was also monitoring during experimentation and they showed the maximum rate of biomass gain, growth (mg weight worm − 1 week − 1 ) and cocoon production rate in T 2, while least values of these parameters were in T 4 treatment. The feasibility of earthworms to mitigate the metal toxicity and to enhance the nutrient profile in sludge might be useful in sustainable land restoration practices at low-input basis.

Effect of Neotyphodium endophyte infection on growth and leaf gas exchange of Arizona fescue under contrasting water availability regimes

We assessed how Neotyphodium infection influenced the biomass production and growth of Arizona fescue ( Festuca arizonica Vasey), a dominant understory grass in Ponderosa pine ( Pinus ponderosa) forests of the southwest USA, by growing potted infected (E+) and uninfected (E−) plants under a high and a low water availability regime for 87 days. We measured growth analysis parameters, leaf net photosynthesis ( P n), chlorophyll fluorescence parameters, conductance to water vapor ( g l) and water potential ( Ψ), to provide explanations for differences in biomass production under these treatments. Under high water availability, E− plants produced more biomass and had greater relative growth rates (RGR; rate of biomass gain per biomass); higher RGR of E− plants was correlated with higher P n as well as production of less dense, presumably thinner leaves, which provided more leaf area per leaf biomass, and greater LAR (leaf area ratio; leaf area per total plant biomass). Under low water availability, E+ plants produced more aboveground biomass and had greater RGR; higher RGR of E+ plants was correlated with higher net assimilation rates, as well as production of less dense leaves and greater LAR. Infected plants tended to have lower midday P n and g l in both water availability regimes. Lower P n in E+ plants appeared primarily due to stomatal, rather than biochemical, limitations to photosynthesis. When a more severe water stress was imposed in the low water availability treatment over the last 61 days of the experiment, E+ plants tended to have higher midday P n and g l. Infected plants also tended to have less negative leaf Ψ regardless of water availability regime. Lower g l and transpirational losses of E+ plants probably conserved soil moisture, such that when a more severe water stress was subsequently imposed, higher soil moisture availability allowed E+ plants to maintain higher P n and g l. Neotyphodium infection appears beneficial to Arizona fescue performance under low water availability and detrimental under ample water availability.

Seed-specific overexpression of a potato sucrose transporter increases sucrose uptake and growth rates of developing pea cotyledons.

During the storage phase, cotyledons of developing pea seeds are nourished by nutrients released to the seed apoplasm by their maternal seed coats. Sucrose is transported into pea cotyledons by sucrose/H+ symport mediated by PsSUT1 and possibly other sucrose symporters. PsSUT1 is principally localised to plasma membranes of cotyledon epidermal and subepidermal transfer cells abutting the seed coat. We tested the hypothesis that endogenous sucrose/H+ symporter(s) regulate sucrose import into developing pea cotyledons. This was done by supplementing their transport activity with a potato sucrose symporter (StSUT1), selectively expressed in cotyledon storage parenchyma cells under control of a vicilin promoter. In segregating transgenic lines, enhanced [(14)C]sucrose influx into cotyledons above wild-type levels was found to be dependent on StSUT1 expression. The transgene significantly increased (approximately 2-fold) transport activity of cotyledon storage parenchyma tissues where it was selectively expressed. In contrast, sucrose influx into whole cotyledons through the endogenous epidermal transfer cell pathway was increased by only 23% in cotyledons expressing the transgene. A similar response was found for rates of biomass gain by intact cotyledons and by excised cotyledons cultured on a sucrose medium. These observations demonstrate that transport activities of sucrose symporters influence cotyledon growth rates. The attenuated effect of StSUT1 overexpression on sucrose and dry matter fluxes by whole cotyledons is consistent with a large proportion of sucrose being taken up at the cotyledonary surface. This indicates that the cellular location of sucrose transporter activity plays a key role in determining rates of sucrose import into cotyledons.

Phytoplankton nutrient limitation and food quality for Daphnia

The influence of nutrient limitation on the quality of Scenedesmus acutus as food for Daphnia obtusa is examined. The nature and degree of nutrient limitation greatly influences the rate at which Daphnia converts Scenedesmus biomass into herbivore biomass. From high to low quality, Scenedesmus food is ranked moderately N limited, severely N limited, and severely P limited. Even a very high concentration (3 mg DW liter−1) of low quality food yields slow Daphnia growth, and it appears that no amount of low quality food would support rapid Daphnia growth. Food‐limited animals display lowered intercepts of length‐weight regressions (prereproductive females), reduced rates of biomass gain (both males and females), increased ages at first reproduction, lowered clutch sizes, increased mortality, and lowered reproductive rate. The N and P contents and the N : P ratio of Scenedesmus all vary considerably under N and P limitation, while the N content (and possibly P content) of Daphnia is less variable and the N : P ratio of Daphnia is essentially constant. Clearance and feeding rates are lower on severely P‐limited cells than on severely N‐limited cells. These results indicate that the mineral nutrition of their algal food may influence the demographics of zooplankton herbivores to a degree not before realized.

White Sucker (Catostomus commersoni) Embryo Development, and Early Growth and Survival at Different Temperatures

White suckers (Catostomus commersoni) were exposed from fertilization through hatching to seven constant temperatures from 6.2 through 24.1 °C. High percentages of apparently normal larvae hatched at temperatures from 9.0 through 17.2 °C. Maximum percent hatch occurred at 15.2 °C, while only a few normal larvae were produced at 6.2 °C, and none at 24.1 °C.Growth rates increased from near zero at 10.0 °C to a maximum at 26.9 °C. At 29.7 °C growth fell below the maximum (P < 0.05), and the incidence of spinal deformities was high. Death rates were uniformly low from 15.7 to 26.9 °C and were significantly higher at 10.0 and 29.7 °C (P < 0.05). The rate of net biomass gain for test groups was maximum at 26.9 °C. Net rates of biomass gain declined progressively with temperatures below 26.9 °C until by 10.0 °C the rate of population growth became less than the rate of weight loss through deaths within the population. The temperature producing maximum hatching success, 15 °C, was nearly 12 °C lower than that providing for maximum growth and net biomass gain.Upper thermal 1-, 2-, and 7-day TL50 values for both newly hatched and swim-up larvae, when acclimated to 9 and 10 °C, were between 28 and 29 °C. When acclimated to 15 and 21 °C, they were between 30 and 32 °C.Lower 1-day TL50 temperature values for both groups of larvae acclimated to 21 °C were near 3 °C (< 2.9), 2-day TL50 values were approximately 0.5 °C higher, and 7-day values were 4.8 °C for newly hatched larvae and 6.1 °C for swim-up larvae.

Effects of Temperature on Growth and Survival of Young Brook Trout, Salvelinus fontinalis

Instantaneous rates of growth, mortality, and net biomass gain were determined for alevin through juvenile brook trout reared for 8 weeks at six constant temperatures: 7.1, 9.8, 12.4, 15.4, 17.9, and 19.5 C. Growth rates were maximum between 12.4 and 15.4 C. Mortality rates increased between 15.4 and 17.9 C and were maximum between 17.9 and 19.5 C. The net rates of biomass gain were maximum between 12.4 and 15.4 C.Median upper thermal tolerance limits (TL50 values) were determined for newly hatched and swim-up alevins. Tolerance did not increase in newly hatched alevins with acclimation to temperatures from 2.5 to 12 C. The upper 7-day TL50 for newly hatched alevins acclimated over this range of temperatures was 20.1 C. The swim-up alevins showed both an increase in temperature tolerance with acclimation temperatures between 7.5 and 12 C and an increase in tolerance over that of the newly hatched alevins at comparable acclimation temperatures. The ultimate 7-day TL50 of swim-up alevins was 24.5 C. Swim-up alevins exceed newly hatched alevins in thermal tolerance by 2.0–4.5 C, depending on the temperature of acclimation. The TL50 of newly hatched alevins of comparable acclimation (12 C) is reduced by about 2 C when the exposure time is increased from 1 to 7 days.

Temperature Requirements for Growth and Survival of Larval Ciscos (Coregonus artedii)

Temperatures above 13 and below 18 C are recommended as most suitable for sustained production of larval cisco, as indicated by instantaneous rates of growth, mortality, and net biomass gain in cisco reared at seven constant temperatures from 3 to 21 C. Growth rates increased in the temperature range from 3 through 18 C. Mortality rates were low from 3 through 13 C, but increased significantly between 13 and 18 C. Net rates of biomass gain were maximum at 13 through 18 C. The 24-hr median lethal temperature for ciscos acclimated to 3 C was calculated to be 19.8 C.