Institute of Horticulture, Anhui Academy of Agricultural Sciences, Hefei, 230031, Anhui Province, China; Key Laboratory of Genetic Improvement and Ecophysiology of Horticultural Crops, Hefei, 230031, Anhui Province, China.
Institute of Horticulture, Anhui Academy of Agricultural Sciences, Hefei, 230031, Anhui Province, China; Key Laboratory of Genetic Improvement and Ecophysiology of Horticultural Crops, Hefei, 230031, Anhui Province, China.
Plant Physiol Biochem. 2019 Jun;139:132-140. doi: 10.1016/j.plaphy.2019.03.013. Epub 2019 Mar 11.
Substrates are fundamental prerequisites for growing grafted seedlings. In this study, substrates with different pH levels (5.0, 5.5, 6.0, 6.5, 7.0, and 8.0) were set up to elucidate the effect of pH on cadmium (Cd) uptake in grafted muskmelon (Cucumis melo L.) plants. Bacterial diversity was also investigated. Results showed that pH and high Cd concentration greatly affected the growth of grafted plants. The chlorophyll content of the muskmelon leaves decreased at 100 μM Cd. The majority of the Cd ions accumulated in the rootstock rather than in the shoot tissue in all of the treatments. The shoots and roots showed the highest Cd content at pH 5.5 and the lowest Cd content at pH 8.0 regardless of the Cd concentration. The operational taxonomic units belonging to Proteobacteria and Bacteroidetes were significantly (p < 0.05) enriched at different substrate pH levels compared with those at pH 5.0. The operational taxonomic units belonging to the phyla Firmicutes, Acidobacteria, and Chloroflexi were significantly decreased. The available nitrogen, phosphorus, Cd, and pH were strongly linked to bacterial community compositions. On the contrary, the available potassium was weakly correlated with the bacterial structure. This study demonstrates that pH greatly affects Cd uptake in grafted muskmelon plants and predicts microbial community structures in breeding substrates with different pH levels. Our results suggest that Cd accumulation in grafted plants can be reduced by setting the appropriate substrate pH. This work can serve as a reference for growing high-quality grafted plants and ensuring food safety in the presence of Cd contamination.
基质是嫁接幼苗生长的基本前提。本研究设置了不同 pH 值（5.0、5.5、6.0、6.5、7.0 和 8.0）的基质，以阐明 pH 值对嫁接薄皮甜瓜（Cucumis melo L.）植株吸收镉（Cd）的影响。还研究了细菌多样性。结果表明，pH 值和高 Cd 浓度极大地影响了嫁接植物的生长。100μM Cd 时，甜瓜叶片的叶绿素含量降低。在所有处理中，大部分 Cd 离子积累在砧木中，而不是在接穗组织中。在所有处理中，无论 Cd 浓度如何，接穗和根系在 pH 5.5 时的 Cd 含量最高，在 pH 8.0 时的 Cd 含量最低。与 pH 5.0 相比，在不同基质 pH 值下，属于变形菌门和拟杆菌门的操作分类单元显著（p<0.05）富集。厚壁菌门、酸杆菌门和绿弯菌门的操作分类单元显著减少。有效氮、磷、Cd 和 pH 与细菌群落组成密切相关。相反，有效钾与细菌结构相关性较弱。本研究表明，pH 值极大地影响嫁接薄皮甜瓜植株对 Cd 的吸收，并预测了不同 pH 值栽培基质中微生物群落结构。我们的结果表明，通过设置合适的基质 pH 值可以减少嫁接植物中的 Cd 积累。这项工作可以为在存在 Cd 污染的情况下种植高质量的嫁接植物和确保食品安全提供参考。
