Calreticulin expression and localization in relation to exchangeable Ca2+ during pollen development in Petunia

Background Pollen development in the anther in angiosperms depends on complicated cellular interactions associated with the expression of gametophytic and sporophytic genes which control fundamental processes during microsporo/gametogenesis, such as exo/endocytosis, intracellular transport, cell signaling, chromatin remodeling, and cell division. Most if not all of these cellular processes depend of local concentration of calcium ions (Ca2+). Work from our laboratory and others provide evidence that calreticulin (CRT), a prominent Ca2+-binding/buffering protein in the endoplasmic reticulum (ER) of eukaryotic cells, may be involved in pollen formation and function. Here, we show for the first time the expression pattern of the PhCRT1 gene and CRT accumulation in relation to exchangeable Ca2+ in Petunia hybrida developing anther, and discuss probable roles for this protein in the male gametophyte development. Results Using northern hybridization, western blot analysis, fluorescent in situ hybridization (FISH), immunocytochemistry, and potassium antimonate precipitation, we report that PhCRT1 is highly expressed in the anther and localization pattern of the CRT protein correlates with loosely bound (exchangeable) Ca2+ during the successive stages of microsporo/gametogenesis. We confirmed a permanent presence of both CRT and exchangeable Ca2+ in the germ line and tapetal cells, where these factors preferentially localized to the ER which is known to be the most effective intracellular Ca2+ store in eukaryotic cells. In addition, our immunoblots revealed a gradual increase in CRT level from the microsporocyte stage through the meiosis and the highest CRT level at the microspore stage, when both microspores and tapetal cells show extremely high secretory activity correlated with the biogenesis of the sporoderm. Conclusion Our present data provide support for a key role of CRT in developing anther of angiosperms – regulation of Ca2+ homeostasis during pollen grains formation. This Ca2+-buffering chaperone seems to be essential for pollen development and maturation since a high rate of protein synthesis and protein folding within the ER as well as intracellular Ca2+ homeostasis are strictly required during the multi-step process of pollen development.

Investigation of soil properties and pesticide intensity in crop lands at Tangail region of Bangladesh

The study was conducted to investigate the soil properties and pesticide intensity in rice, banana and brinjal growing agricultural land of Delduar and Sakhipur upazila of Tangail district during July 2019 to June 2020. Forty five soil samples were collected from different crop land at the study area and analyzed in the Soil Resource Development Institute to determine the soil properties as pH, total organic matter (OM), total nitrogen (N), available phosphorus (P), available sulfur (S), available zinc (Zn), exchangeable potassium (K), exchangeable magnesium (Mg) and exchangeable calcium (Ca). However, pesticide used intensity was also evaluated through questionnaire survey with farmers and stakeholders in the study area. Results showed that pH, OM, available N, exchangeable Ca and exchangeable Mg content were significantly higher in rice growing land than banana and brinjal. On the other hand, available P, exchangeable K and available Zn content were substantially higher in brinjal growing land than rice and banana. The OM showed significant positive correlation with soil pH, available N, available S, exchangeable Mg and exchangeable Ca (r=0.37, 0.99, 0.31, 0.59 and 0.63, respectively), indicated rice growing land built up these soil properties through increasing soil OM. The available P showed significant and positive correlation with K and Zn (r=0.55 and 0.74, respectively), but negative correlation with exchangeable Mg and exchangeable Ca (r=-0.53 and -0.32, respectively). The exchangeable K showed significant and positive correlation with available Zn (r=0.45) but negative correlation with exchangeable Mg (r=-0.37). The Mg showed significant negative correlation with available Zn (r=-0.45) but positive correlation with exchangeable Ca (r=0.87). Results also revealed that pesticide used intensity was higher in brinjal followed by banana and minimum in rice crop. Study suggests that farmers require up-to-date information on soil nutrient status so that they may use the proper utilization of fertilizers and avoid using excessive amounts of fertilizers and pesticides in their crop land. Int. J. Agril. Res. Innov. Tech. 11(2): 85-94, Dec 2021

Gypsum and potassium application to acid soils for maize (Zea mays L.) production in La Frailesca, Chiapas, Mexico

Introduction. Maize (Zea mays L.) production in La Frailesca region, Mexico, is limited by sandy soils, low in potassium (K), and with acidic arable layers and subsoils. There is information on the management of lime but not on amendments that could be used for subsoil acidity — such as gypsum — nor on the interactions between amendments for soil acidity and K fertilization. Objective. To evaluate the effects of K and gypsum on maize and on previously limed soils. Materials and methods. The evaluations were conducted in farmers’ fields in La Frailesca region, Chiapas (Mexico) in 2016 and 2017. Four gypsum rates (0, 1.25, 2.5 and 5 t ha-1) and four K rates (0, 60, 90, and 120 kg ha-1 as K2O) were factorially combined in a randomized block design, with three replicates. In both years, before the beginning of the experiments, dolomitic lime was applied to the experimental area following standard practices. Responses of crop yield, soil exchangeable K, Ca, Mg, and Al, and soil pH were obtained. Results. Maize yields increased with gypsum (stabilizing at 1.25-3.0 t ha-1), and K (stabilizing at 70-120 kg ha-1 of K2O) applications. In soils, K application increased exchangeable K content, while gypsum increased exchangeable Ca content and pH, and decreased exchangeable Al content. Liming increased pHCa and exchangeable Ca and Mg contents, and lowered the exchangeable Al content in the top 7.5 cm of soil. Conclusion. Soils with exchangeable K (≤0.3 cmolc kg-1) were responsive to K fertilization. The positive effects on yields from gypsum were probably linked to a greater Ca supply in the top 7.5 cm. These results are encouraging about the benefits of the combined application of dolomitic lime, gypsum, and K, but longer evaluations are needed to properly determine the effects of gypsum on subsoil acidity.

Effect of Acacia mangium Canopy on Physicochemical Characteristics and Nutrient Concentrations of the Soil at Ayer Hitam Forest Reserve, Malaysia

The establishment of an Acacia mangium plantation often alters physicochemical characteristics and nutrient concentrations of soils. We aimed to evaluate the invasive potential of A. mangium forest on the soil in Ayer Hitam Forest Reserve, Peninsular, Malaysia. To achieve the mentioned target, four different regions, namely, the open ground region (OG), Acacia mangium region (AM), transition region (TZ), and native forest region (NF), were selected and each of the regions was divided into six plots. Composite samples were randomly taken from subplots at 0–15 cm depth (topsoil) and 15–30 cm depth (subsoil). Some physicochemical properties such as soil moisture and texture, textural classification, bulk density and particle density, pH, electric conductivity (EC), exchangeable bases (EB) (Ca, Mg and K), cation exchange capacity (CEC), organic matter (OM), total nitrogen (TN), and available phosphorous (Av. P) were analyzed. The results of our study showed that the soil of the AM region, which was clay loam, contained clay (51%), silt (32%), and sand (16%). The chemical analysis of topsoil showed significant differences in terms of OM%, exchangeable- Ca, Mg, K (molc kg−1), N (%), gravitational water content (GWC), and Avail. P between all four regions. Additionally, the highest pH and OM of topsoil were seen in the AM region with 4.5% and 4.33%, respectively. In the subsoil, there were significant differences (p ≤ 0.01) in terms of EC (ds/m), OM (%), Exchangeable- Ca, Mg and K (cmolc kg−1), GWC, available phosphorus, and N (%) between all four regions. The highest GWC, N (%), and Ca (cmolc kg−1) were observed in the AM region with 16.00, 0.14%, and 0.64 cmolc kg−1, respectively. These results showed that A. mangium changed some soil characteristics due to its invasion potential. In summary, A. mangium showed high adaptability on degraded forest land and high ability to accumulate the soil physicochemical properties to enhance its growth.

Continental-scale controls on soil organic carbon across sub-Saharan Africa

Soil organic carbon (SOC) stabilization and destabilization has been studied intensively. Yet, the factors which control SOC content across scales remain unclear. Earlier studies demonstrated that soil texture and geochemistry strongly affect SOC content. However, those findings primarily rely on data from temperate regions where soil mineralogy, weathering status and climatic conditions generally differ from tropical and subtropical regions. We investigated soil properties and climate variables influencing SOC concentrations across sub-Saharan Africa. A total of 1601 samples were analyzed, collected from two depths (0–20 and 20–50 cm) from 17 countries as part of the Africa Soil Information Service project (AfSIS). The data set spans arid to humid climates and includes soils with a wide range of pH values, weathering status, soil texture, exchangeable cations, extractable metals and land cover types. The most important SOC predictors were identified by linear mixed-effects models, regression trees and random forest models. Our results indicate that geochemical properties, mainly oxalate-extractable metals (Al and Fe) and exchangeable Ca, are equally important compared to climatic variables (mean annual temperature and aridity index). Together, they explain approximately two-thirds of SOC variation across sub-Saharan Africa. Oxalate-extractable metals were most important in wet regions with acidic and highly weathered soils, whereas exchangeable Ca was more important in alkaline and less weathered soils in drier regions. In contrast, land cover and soil texture were not significant SOC predictors on this large scale. Our findings indicate that key factors controlling SOC across sub-Saharan Africa are broadly similar to those in temperate regions, despite differences in soil development history.

An Assessment of the Physico-Chemical Parameters of Mangrove Soils that Support Nypa fruticans and Other Mangrove Species Establishment in the Cameroon Estuary

Invasion of Nypa palm into mangroves is a problem in the Cameroon Estuary. Soil variability is one of the dominant features that support Nypa palm establishment. The objective was to characterize the soil under the different mangrove stands; Purely Nypa palm stands (A), mixed stands i.e Nypa palm and other mangrove species (B) and other mangrove species i.e Nypa palm free (C), determine the principal soil characteristic critical for Nypa spread. 9 plots of 20 x 20 m were laid in each of the sites. 27 soil samples were collected in the North, West, South East and Center at a depth of 30 cm in these three sites using a soil auger. The results in the three sites indicated that; soils were acidic (3.87- 4.39), pH values did not significantly differ (alpha >0.05), organic matter was low in A (12.32%) and B (16.35%).Soil Organic Carbon ranged from (4.52 to 7.06%). High percentage of organic carbon content was recorded in C (7.06%). Low percentage of organic carbon was found in A (4.52%). Total nitrogen varied from 1.04 g/kg, 1.70g/kg, 1.80 g/kg in sites C, A and B. In all the mangrove stands, the values of Exchangeable Ca content were below 4.0 cmolkg-1. Soil texture in the three sites were; sandy, clay and silt. Power test showed no significant different in soil types between the three sites (p>0.05). According to the component matrix the factor is positively loaded by soil EC, moisture content, organic matter, organic carbon, N, C/N, CEC, Ca, Mg, K, Na, Clay, Silt, and negatively loaded by the percent sand. This study therefore, suggests that since soil plays key role in Nypa palm establishment, there should be constant monitoring of soil quality to forestall drastic changes that will jeopardize the survival of the mangroves. Nypa palm seedlings should also be physically removed from mangrove forest to prevent colonization. In addition, more mangrove seeds should be planted in deforested mangrove areas to close the window of opportunity for the palms.

Retention of the Antibiotic Cefuroxime onto Agricultural and Forest Soils

Antibiotics in wastewater, sewage sludge, manures, and slurries constitute a risk for the environment when spread on soils. This work studies the adsorption and desorption of the antibiotic cefuroxime (CFX) in 23 agricultural and forest soils, using batch-type experiments. Our results show that the adsorption values were between 40.75 and 99.57% in the agricultural soils, while the range was lower (from 74.57 to 93.46%) in forest soils. Among the Freundlich, Langmuir, and Linear models, the Freundlich equation shows the best fit for the adsorption results. In addition, agricultural soils with higher pH are the ones that present the highest adsorption. Further confirmation of the influence of pH on adsorption is given by the fact that Freundlich’s KF parameter and the Linear model Kd parameter shows a positive correlation with pH and with the exchangeable Ca and Mg values, which are known to affect the charges of the soil colloids and the formation of cationic bridges between adsorbents and adsorbate. In addition, Freundlich’s n parameter shows a positive and significant correlation with the organic matter content, related to the high adsorption taking place on forest soils despite their pH < 5. Regarding desorption, in most cases, it is lower than 1%, which indicates that CFX is adsorbed in a rather irreversible way onto these soils. Overall, these results can be considered relevant regarding their potential impact on environmental quality and public health.

Soil fertility indices of tropical loamy sand as influenced by bambara groundnut variety, plant spacing and fertilizer type

Agricultural sustainability ensues when cultivation of field crops and associated techniques improve not just crop yields but also management-responsive soil properties. Bambara groundnut as an underutilized crop lacks research-based information on its agronomic requirements. This paper reports the key fertility indices of a loamy-sand soil in southeastern Nigeria as influenced by soil and agronomic management practices involving factorial combinations of two bambara groundnut varieties (Caro and Olokoro), two plant spacings (30 cm × 75 cm and 45 cm × 75 cm) and four organic/inorganic fertilizer options. These fertilizer options were NPK 15-15-15 (NPK), single super phosphate (SSP), poultry manure (PM) and Control. The plots under Caro variety spaced 30 cm × 75 cm and grown with NPK or SSP fertilizer showed the highest CEC (8.40 cmol kg–1) and exchangeable K (0.15 cmol kg–1), respectively. Olokoro variety spaced 45 cm × 75 cm and grown with PM or SSP gave the highest total nitrogen (0.14%), soil pHwater (6.35), available phosphorus (107.60 mg kg-1) and exchangeable Ca (3.70 cmol kg-1). The interactions plant spacing × fertilizer type and crop variety × fertilizer type affected all the soil fertility indices studied, while crop variety × plant spacing affected soil pHwater, available phosphorus, CEC and exchangeable Ca and Mg. Generally, as main factors, Olokoro variety, NPK and 45 cm × 75 cm improved soil properties better than their counterparts.

Soil Nutrients Status and Cotton Yield as Influenced by Split Application of Nitrogen and Potassium in Vertisol

The present investigation was conducted during 2018-19 with a view to study the effect of split application of nitrogen and potassium on yield of cotton and soil nutrient status at Dr. Panjabrao Deshmukh Krishi Vidyapeeth, Akola. The experiment comprised of eight different treatments and their combination with foliar spray of 1 per cent MgSO4 at two different growth stages viz. flowering and boll development in randomized block design with three replications. The results of the present experiment revealed that, available nutrient status of soil was slightly increased with increase in the splits of N and K fertilizer. Available N, P, K, S and exchangeable Ca in soil were significantly increased with the split application of fertilizer. The fertilizer split did not show significant effect on the exchangeable magnesium status of soil. Foliar sprays of 1 per cent MgSO4 at two different growth stages viz. flowering and boll development irrespective of fertility levels showed slightly higher exchangeable magnesium status of soil. The lowest available N, P, K, S and exchangeable Ca and Mg was recorded in treatment of absolute control. The fertilizer splits show a consistent increase in the seed cotton yield and stalk yield of Bt cotton. Hence, it can be concluded that, application of 60:30:30 N, P2O5 and K2O kg ha-1 with splits of nitrogen at basal, 30, 60 and 90 DAS, 100 per cent P2O5 as basal and K2O in two equal splits at basal and 60 DAS recorded significantly higher seed cotton and cotton stalk yield. The seed cotton (R2 = 0.913**) and stalk yield (R2 = 0.935**) was significantly and positively correlated with the soil organic carbon status.

Effect of Savanna windrow wood burning on the spatial variability of soil properties

ABSTRACT Tropical Savannas cover an area of approximately 1.9 billion hectares around the word and are subject to regular fires every 1 to 4 years. This study aimed to evaluate the influence of burning windrow wood from Cerrado (Brazilian Savanna) deforestation on the spatial variability of soil chemical properties, in the field. The data were analysed by using geostatistical methods. The semivariograms for pH(H2O), pH(CaCl2), Ca, Mg and K were calculated according to spherical models, whereas the phosphorus showed a nugget effect. The cross semi-variograms showed correlations between pH(H2O) and pH(CaCl2) with other variables with spatial dependence (exchangeable Ca and Mg and available K). The spatial variability maps for the pH(H2O), pH(CaCl2), Ca, Mg and K concentrations also showed similar patterns of spatial variability, indicating that burning the vegetation after deforestation caused a well-defined spatial arrangement. Even after 20 years of use with agriculture, the spatial distribution of pH(H2O), pH(CaCl2), Ca, Mg and available K was affected by the wood windrow burning that took place during the initial deforestation.