Variable effects of biostimulants on growth of Chenopodium spp under abiotic stress

Abiotic stressors such as drought, high heat, and nutrient depletion greatly impact agricultural yields. Many plant-associated beneficial microorganisms can alleviate the effects of abiotic stress on crops by producing phytohormones, increasing water access, and transforming soil nutrients to bioavailable forms for plant uptake. These beneficial microbes have the potential to reduce our use of traditional chemical fertilizers without sacrificing crop productivity. The objectives of this study were to evaluate the effects of biostimulants and abiotic stress on the growth of 1) Chenopodium quinoa and 2) its wild relative C. ficifolium. We performed controlled environment growth room studies to evaluate the effect of one commercial biostimulant and two novel bacterial strains isolated from C. berlandieri (NFB28.1 and PSB37.3) on C. quinoa growth under drought and nutrient-depleted conditions. We also evaluated the effect of a commercial biostimulant, Lalrise Start SC, on C. ficifolium as a potential model for inferring microbial interactions with quinoa. Our results show that NFB28.1 (Achromobacter insolitus) and PSB37.3 (Microbacterium sp.) did not impact plant growth under stress conditions compared to water controls. However, Lalrise Start SC significantly increased quinoa aboveground biomass and photosynthetic activity under drought and nutrient stress, respectively. Here we show that C. ficifolium may not be an adequate model for quinoa to predict microbial interactions however, more research must be done to compare the effectiveness of biostimulants on these two species. This study is the first to characterize of the effects of a commercial biostimulant on C. quinoa and C. ficifolium, as well as the first in vivo characterization of the impact of New Hampshire soil microbes on quinoa.干旱、高温与养分耗竭等非生物胁迫（abiotic stressors）会对农业产量造成严重负面影响。诸多植物相关有益微生物可通过产生植物激素（phytohormones）、提升作物水分获取能力，以及将土壤养分转化为植物可吸收利用的生物有效形态（bioavailable forms），来缓解非生物胁迫对作物的危害。这类有益微生物有望在不降低作物生产力的前提下，减少传统化学肥料的使用量。本研究的目的在于评估生物刺激素（biostimulants）与非生物胁迫对1) 藜麦（Chenopodium quinoa）以及2) 其野生近缘种C. ficifolium生长的影响。我们开展了可控环境生长室试验，以评估1种商用生物刺激素，以及从C. berlandieri中分离得到的两株新型细菌菌株（NFB28.1与PSB37.3）在干旱与养分匮乏条件下对藜麦生长的作用效果；同时还评估了商用生物刺激素Lalrise Start SC对C. ficifolium的影响，将其作为推断藜麦与微生物互作关系的潜在模式物种。研究结果显示，与水处理对照组相比，NFB28.1（不溶性无色杆菌Achromobacter insolitus）与PSB37.3（微杆菌属物种Microbacterium sp.）在胁迫条件下并未对植物生长产生显著影响。然而，Lalrise Start SC可分别在干旱与养分胁迫条件下，显著提升藜麦的地上生物量（aboveground biomass）与光合活性（photosynthetic activity）。本研究表明，C. ficifolium或许并非用于预测藜麦微生物互作的合适模式物种，但仍需开展更多研究以对比生物刺激素在这两个物种上的应用效果。本研究首次表征了商用生物刺激素对藜麦（Chenopodium quinoa）与C. ficifolium的影响，同时也是首次在体表征新罕布什尔州土壤微生物对藜麦的作用效果。