Jiang Tianchi, Chen Jiuzhou, Huang Yu, Chang Xiaoyan, Wu Yuping, Liu Gaoping, Wang Runze, Xu Kuan, Lu Lingli, Lin Haizhong, Tian Shengke
Ministry of Education (MOE) Key Laboratory of Environmental Remediation and Ecological Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, China.
Xiangshan Agricultural and Rural Bureau, Ningbo, China.
Front Plant Sci. 2024 Feb 20;14:1335843. doi: 10.3389/fpls.2023.1335843. eCollection 2023.
Citruses often occur with imbalance in iron nutrition in coastal saline-alkali lands, which severely limits the yield and quality of the fruit. In the rhizosphere, the salt content plays a crucial role in reducing uptake of iron, as well as the activity and abundance of bacteria. However, few studies have explored how salt content affects the effectiveness of iron and the community structure of bacteria across different vertical spatial scales.
We investigated the citrus rhizosphere (0-30 cm) and bulk (0-60 cm) soil microenvironments of the coastal saline soil were analyzed using the 16S rRNA amplicon and inductively coupled plasma-optical emission spectroscopy.
We found that the nutrient-related elements in the rhizosphere and bulk soil decreased with increasing soil depth, while the salinity-related elements showed the opposite trend. The nutrient-related element content in the rhizosphere was higher than that in the bulk, whereas the salinity-alkaline-related element content was lower than that in the bulk. The structure and diversity of bacterial communities are affected by the rhizosphere and soil depth. In the bulk, there are enriched bacteria such as WB1-A12, Nitrospiraceae and Anaerolineae that are tolerant to salt-alkali stress. In the rhizosphere, bacteria that promote plant nutrient absorption and secretion of iron carriers, such as , , and , are prominent.
The soil depth and rhizosphere affect soil nutrients and saline alkali-related factors. Changes in soil depth and rhizosphere determine the structure and diversity of bacterial communities. Rhizosphere enhances iron absorption promoting bacteria to alleviate iron deficiency stress in saline-alkali soils. Our results indicate that citrus roots maybe can resist the stress of iron deficiency in saline-alkali soils by enhancing iron absorption promoting bacteria.
在沿海盐碱地，柑橘常出现铁营养失衡的情况，这严重限制了果实的产量和品质。在根际，盐分含量对铁的吸收以及细菌的活性和丰度起着关键作用。然而，很少有研究探讨盐分含量如何在不同垂直空间尺度上影响铁的有效性和细菌群落结构。
我们调查了沿海盐土的柑橘根际（0 - 30厘米）和土体（0 - 60厘米）土壤微环境，采用16S rRNA扩增子和电感耦合等离子体发射光谱法进行分析。
我们发现，根际和土体土壤中与养分相关的元素随土壤深度增加而降低，而与盐分相关的元素则呈现相反趋势。根际中与养分相关的元素含量高于土体，而与盐碱相关的元素含量低于土体。细菌群落的结构和多样性受根际和土壤深度的影响。在土体中，富集了如WB1 - A12、硝化螺旋菌科和厌氧绳菌科等耐盐碱胁迫的细菌。在根际，促进植物养分吸收和铁载体分泌的细菌，如[此处原文缺失具体细菌名称]、[此处原文缺失具体细菌名称]和[此处原文缺失具体细菌名称]较为突出。
土壤深度和根际影响土壤养分和盐碱相关因素。土壤深度和根际的变化决定了细菌群落的结构和多样性。根际增强铁吸收促进细菌以缓解盐碱土中的缺铁胁迫。我们的结果表明，柑橘根系可能通过增强铁吸收促进细菌来抵抗盐碱土中的缺铁胁迫。
