Patra, A. K. | Search bioRxiv

bioRxiv2026

Inward thickening of embryonic neuron-packing brain walls: Mechanical integrity via curvature-associated inner-surface contractility

Despite recent explorations of tissue-level epithelial morphogenesis, how the embryonic brain wall, an epithelial derivative unique in its extensive cellular stratification coupled with epithelial-cell heightening to [~]0.5 mm, achieves thickening is unknown. Furthermore, the role of the inner curvature of the wall in this process remains unclear. Thus, whether the apically concave dorsal cerebral (pallial) wall thickens inward, not only outward as previously thought, was examined in culture and in vivo. The pallial wall in the midembryonic period, but not the earlier pallial wall, thickened inward at a pace equivalent to that of neuronal accumulation, which was found via stress-release tests to proceed in a compressive manner. The inhibition of actomyosin-mediated contraction of the inner/apical surface prevented the pallium from thickening, while inducing apical-surface buckling, suggesting the necessity of this inward thickening to actively avoid overcrowding. In contrast, inward bulging of the apically convex ganglionic eminence occurs more passively via pushing of the low-actomyosin apical surface by the constituent cells.

developmental biology↗

bioRxiv2020

Modified split application of nitrogen with biochar improved grain yield and nitrogen use efficiency in rainfed maize grown in Vertisols of India

Conventionally, non-judicious and blanket fertilizer nitrogen (N) used in rainfed maize lead to higher N losses, low N use efficiency (NUEs) and poor yields due to substandard agronomic management practices. To avoid such N losses, fertilizer additions are synchronized with plant uptake requirements. In this context, agronomic based management focused on optimizing N rates and biochar application is essential for improved NUEs and crop productivity. Keeping this in view, a field experiment was conducted during 2014, 2015 and 2016 in rainfed maize (Zea mays L.) grown in Vertisols of India. In this study, twelve treatments that comprised of N omission plot (N0), skipping of basal rate, multi-split topdressing at varying time as broadcast and band placement, soil test crop response (STCR) based NPK with target yield 6.0 t ha-1 in maize and biochar application (10 t ha-1) were investigated. The experiment was conducted following a Randomized Complete Block Design (RCBD) set up with three replications. Pooled analysis of three years data revealed that the application of N rates (120 kg Nha-1) in 2 equal splits (60 kg Nha-1) at knee high (V8) and tasseling (VT) stages with skipped basal N rate, achieved higher maize grain yield (5.29 t ha-1) ascribed to the greater growth parameters, yield components and N uptake compared to the recommended practices. Biochar application (10 t ha-1) as soil amendments along with multi top dressed N (120 kg N ha-1) into 3 splits also increased the grain yield. Delayed N application at V8 and VT growth stages, resulted in higher N uptake, agronomy efficiency (AE), partial factor productivity (PFP), physiology efficiency (PE) and recovery efficiency (RE). Biochar along with N fertilizer also improved the soil organic carbon (5.47g kg-1), ammonium-N (2.40 mg kg-1) and nitrate-N (0.52 mg kg-1) concentration in soil (P<0.05) as compared to non-biochar treatments. Application of biochar along with chemical fertilizer (120 kg Nha-1) significantly increased the concentration of ammonium (2.40 mg kg-1) and nitrate (0.52 mg kg-1) in soil (P<0.05) as compared to non-biochar treatments. The perfect positive linear relationship illustrated that the grain yield of rainfed maize was highly dependent (R2=0.99 at p<0.0001) on N availability, as indicated by the fitted regression line of maize grain yield on N uptake. On the other hand, factor analysis revealed, the one to one positive function relationship of biomass with N uptake at V8 and VT growth stages. Principal Component Regression (PCR) analysis showed that PC1 acted as a major predictor variable for total dry matter yield (TDMY) and dominated by LAI and N uptake. Consequently, these results expressed that the agronomic management based multi-top dressed N application and biochar application to achieve higher yield and greater NUEs in rainfed maize is strongly linked with N application into splits.

plant biology↗