PDF(Pubmed)
Abstract：
Considering current global climate change, drought stress is regarded as a major problem negatively impacting the growth of soybeans, particularly at the critical stages R3 (early pod) and R5 (seed development). Microbial inoculation is regarded as an ecologically friendly and low-cost-effective strategy for helping soybean plants withstand drought stress. The present study aimed to isolate newly drought-tolerant bacteria from native soil and evaluated their potential for producing growth-promoting substances as well as understanding how these isolated bacteria along with arbuscular mycorrhizal fungi (AMF) could mitigate drought stress in soybean plants at critical growth stages in a field experiment. In this study, 30 Bradyrhizobium isolates and 30 rhizobacterial isolates were isolated from the soybean nodules and rhizosphere, respectively. Polyethylene glycol (PEG) 6000 was used for evaluating their tolerance to drought, and then the production of growth promotion substances was evaluated under both without/with PEG. The most effective isolates (DTB4 and DTR30) were identified genetically using 16S rRNA gene. A field experiment was conducted to study the impact of inoculation with DTB4 and DTR30 along with AMF (Glomus clarum, Funneliformis mosseae, and Gigaspora margarita) on the growth and yield of drought-stressed soybeans. Our results showed that the bioinoculant applications improved the growth traits (shoot length, root length, leaf area, and dry weight), chlorophyll content, nutrient content (N, P, and K), nodulation, and yield components (pods number, seeds weight, and grain yield) of soybean plants under drought stress (p ≤ 0.05). Moreover, proline contents were decreased due to the bioinoculant applications under drought when compared to uninoculated treatments. As well as the count of bacteria, mycorrhizal colonization indices, and the activity of soil enzymes (dehydrogenase and phosphatase) were enhanced in the soybean rhizosphere under drought stress. This study\'s findings imply that using a mixture of bioinoculants may help soybean plants withstand drought stress, particularly during critical growth stages, and that soybean growth, productivity, and soil microbial activity were improved under drought stress.
摘要：
考虑到当前的全球气候变化，干旱胁迫被认为是影响大豆生长的主要问题，特别是在关键阶段R3（早期豆荚）和R5（种子发育）。微生物接种被认为是一种生态友好且低成本有效的策略，可帮助大豆植物抵御干旱胁迫。本研究旨在从天然土壤中分离出新的耐旱性细菌，并评估其产生生长促进物质的潜力，以及了解这些分离的细菌与丛枝菌根真菌（AMF）如何减轻大豆植物在关键生长阶段的干旱胁迫在田间实验中。在这项研究中,从大豆根瘤和根际分离出30株根瘤菌和30株根际根瘤菌，分别。聚乙二醇（PEG）6000用于评估其对干旱的耐受性，然后在没有/有PEG的情况下评估生长促进物质的产生。使用16SrRNA基因遗传鉴定了最有效的分离株（DTB4和DTR30）。进行了一项田间试验，以研究用DTB4和DTR30以及AMF（Glomusclarum，真菌，和Gigasporamargarita）关于干旱胁迫大豆的生长和产量。我们的结果表明，生物接种剂的应用改善了生长性状(芽长度，根长,叶面积,和干重)，叶绿素含量，营养成分(N，P,andK),结瘤,和产量成分(豆荚数量，种子重量,和谷物产量）在干旱胁迫下的大豆植物（p≤0.05）。此外，与未接种处理相比，由于干旱下的生物接种剂应用，脯氨酸含量降低。以及细菌的数量，菌根定植指数，干旱胁迫下大豆根际土壤酶(脱氢酶和磷酸酶)活性增强。这项研究的发现暗示，使用生物接种剂的混合物可以帮助大豆植物抵御干旱胁迫，特别是在关键的生长阶段，大豆的生长，生产力,干旱胁迫下土壤微生物活性得到改善。
