Ogwu, M. C. | Search bioRxiv

bioRxiv2021

Implications of soil nitrogen enhancement on the yield performance of soybean (Glycine max) in cadmium-polluted soil

The growth, development and yield of important crop plants like soybean (Glycine max) are constantly under threat by continuous inputs of cadmium in the biosphere as a result of various industrial activities. This study investigated the level to which, addition of nitrogen fertilization can enhance plant survival, growth and yield development in a cadmium-polluted. Three accessions of Glycine max (TGm - 1, TGm - 2 and TGm - 3) were sown in a 12 mg/kg-cadmium polluted, which was thereafter amended with urea (FU), ammonia (FA), and ammonium nitrate (FN) singly and in combinations of equal proportions. A non-fertilized Cd-polluted soil and a general control constituted the negative and positive controls. Results showed that although N application did not enhance yield dispositions of soybean in Cd-polluted soil, significant impact on vegetative development was noteworthy. Compared to yield of control plants, cadmium pollution imposed a 26.1 % reduction in per plant yield in TGm-1, compared 1.71 % in TGm-3. Generally, addition of nitrogenous fertilizer further suppressed crop yield by as much as 80 % in plants sown in cadmium-polluted soil. However, application of ammonia fertilizer to TGm-2 improved its yield performances in the cadmium-polluted soil.

plant biology↗

bioRxiv2021

Elevation-related climate trends dominate fungal co-occurrence patterns on Mt. Norikura, Japan

Although many studies have explored patterns of fungal community diversity and composition along various environmental gradients, the trends of co-occurrence networks across similar gradients remain elusive. Here, we constructed co-occurrence networks for fungal community along a 2300 m elevation gradient on Mt Norikura, Japan, hypothesizing a progressive decline in network connectivity with elevation due to reduced niche differentiation caused by declining temperature and ecosystem productivity. Results agreed broadly with predictions, with an overall decline in network connectivity with elevation for all fungi and the high abundance phyla. However, trends were not uniform with elevation, most decline in connectivity occurred between 700 m and 1500 m elevation, remaining relatively stable above this. Temperature and precipitation dominated variation in network properties, with lower mean annual temperature (MAT) and higher mean annual precipitation (MAP) at higher elevations giving less network connectivity, largely through indirect effects on soil properties. Among keystone taxa that played crucial roles in network structure, the variation in abundance along the elevation gradient was also controlled by climate and also pH. Our findings point to a major role of climate gradients in mid-latitude mountain areas in controlling network connectivity. Given the importance of the orographic precipitation effect, microbial community trends seen along elevation gradients might not be mirrored by those seen along latitudinal temperature gradients. ImportanceAlthough many studies have explored patterns of fungal community diversity and composition along various environmental gradients, it is unclear how the topological structure of co-occurrence networks shifts across environmental gradients. In this study, we found that the connectivity of the fungal community decreased with increasing elevation, and that climate was the dominant factor regulating co-occurrence patterns, apparently acting indirectly through soil characteristics. Assemblages of keystone taxa playing crucial roles in network structure varied along the elevation gradient and were also largely controlled by climate. Our results provide insight into the shift of soil fungal community co-occurrence structure along elevational gradients, and possible driving mechanisms behind this. Graphic abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=159 SRC="FIGDIR/small/428196v1_ufig1.gif" ALT="Figure 1"> View larger version (27K): org.highwire.dtl.DTLVardef@12e555aorg.highwire.dtl.DTLVardef@e5c4d7org.highwire.dtl.DTLVardef@de00bdorg.highwire.dtl.DTLVardef@102967c_HPS_FORMAT_FIGEXP M_FIG C_FIG

microbiology↗