Biochar is colonized by select arbuscular mycorrhizal fungi in agricultural soils.

Arbuscular mycorrhizal fungi (AMF) colonize biochar in soils, yet the processes governing their colonization and growth in biochar are not well characterized. Biochar amendment improves soil health by increasing soil carbon, decreasing bulk density, and improving soil water retention, all of which can increase yield and alleviate environmental stress on crops. Biochar is often applied with nutrient addition, impacting mycorrhizal communities. To understand how mycorrhizas explore soils containing biochar, we buried packets of non-activated biochar in root exclusion mesh bags in contrasting agricultural soils. In this greenhouse experiment, with quinoa (Chenopodium quinoa) as the host plant, we tested impacts of mineral nutrient (as manure and fertilizer) and biochar addition on mycorrhizal colonization of biochar. Paraglomus appeared to dominate the biochar packets, and the community of AMF found in the biochar was a subset (12 of 18) of the virtual taxa detected in soil communities. We saw differences in AMF community composition between soils with different edaphic properties, and while nutrient addition shifted those communities, the shifts were inconsistent between soil types and did not significantly influence the observation that Paraglomus appeared to selectively colonize biochar. This observation may reflect differences in AMF traits, with Paraglomus previously identified only in soils (not in roots) pointing to predominately soil exploratory traits. Conversely, the absence of some AMF from the biochar implies either a reduced tendency to explore soils or an ability to avoid recalcitrant nutrient sources. Our results point to a selective colonization of biochar in agricultural soils.

Arbuscular mycorrhizal fungi in oat-pea intercropping.

Arbuscular mycorrhizal fungal diversity can be altered by intercropping plant species, as well as N fertilizer applications. This study examined the effects of oat-pea intercropping and N fertilizer addition on the richness and diversity of mycorrhizal species, as well as identified the most common arbuscular mycorrhizal fungi (AMF) genera recruited for oats and peas in two growing seasons (2019 and 2020). The AMF diversity was higher in an intercropped system compared to their respective monocropping system. Under drier conditions in 2019, arbuscular mycorrhizal richness decreased with N fertilizer addition in sole peas and increased with N fertilizer addition in sole oats, but no significant change in richness was observed in oat-pea intercropping. During the wetter growing season 2020, arbuscular mycorrhizal diversity increased when oat and pea were intercropped, compared to either sole oat or sole pea. Diversispora in sole pea was a significant indicator differentiating the root associated AMF community from sole oat. Claroideoglomus richness increased in peas in 2020, thus this genus could be moisture dependent. Paraglomus richness in oat-pea intercropping was similar to sole oat in 2019, and similar to sole pea in 2020. This can suggest that Paraglomus is an indicator of plant stress under intercropping, as based on the premise that stressed plants release more exudates, and the subsequent mycorrhizal associations favor these plants with higher exudation. Future investigations can further reveal the functions and benefits of these mycorrhizal genera in annual monocrop and intercropping systems.

Hand Functions of Myoelectric and 3D-Printed Pressure-Sensored Prosthetics: A Comparative Study.

The loss of an upper limb significantly limits the functional activities of daily living. A huge emphasis is placed on the manipulation, shape, weight, and comfort of a prosthesis, to enable its use as an inherent body part. Even with technological advances, customized upper-extremity myoelectric prosthesis remain heavy and expensive. The high cost of upper-extremity prosthesis is an especially steep economic barrier for patients. Three-dimensional (3D) printing is a promising avenue for reducing the cost of prosthesis. We applied 3D-printed pressure-sensored prosthetics to a traumatic transradial amputee, and compared the hand functions with a customized myoelectric prosthesis. The 3D-printed pressure-sensored prosthetics showed low grip strength and decreased dexterity compared to the conventional myoelectric prosthesis. Although there were a few limitations, the fabrication of prosthesis with 3D printing technology can overcome previous problems such as high production cost, long fabrication period and heavy weight.