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不同磷水平对花榈木幼苗根系形态及磷素吸收的影响

来源：花匠小妙招时间：2025-06-22 14:05

摘要： 磷是植物生长发育必需的大量元素之一。不同植物根系生长对不同磷水平的反应不尽相同。花榈木（Ormosia henryi Hemsl. & E. H. Wilson）是一种珍惜濒危植物，具有重要的经济和生态价值。为了探究花榈木对不同磷水平的响应，本研究以2年生花榈木幼苗为材料，在改良Hoagland营养液基础上设置0（P0）、0.5（P1）、1.0（P2）、2.0（P3）、4.0（P4） mmol·L-1 5个磷水平处理，分析不同磷水平对花榈木幼苗根系形态及磷素吸收的影响。结果表明：（1）1.0 mmol·L-1处理下花榈木幼苗根系的总根长、总根表面积、总根体积、根平均直径和根系活力均最大，而4.0 mmol·L-1处理下的最小。（2）0.5 mmol·L-1处理下幼苗根基部和根中部分泌的酸性磷酸酶活性较高，1.0 mmol·L-1处理下幼苗根中部和根尖分泌的酸性磷酸酶活性较高，显著大于无磷和高磷处理（2.0和4.0 mmol·L-1）。（3）1.0 mmol·L-1处理下花榈木根系分泌的有机酸种类和总量均为最大，无磷和0.5 mmol·L-1处理下的幼苗分泌的有机酸种类和总量显著大于高磷处理（2.0和4.0 mmol·L-1）。（4）与无磷处理组相比，施磷均增大了幼苗地上部和根系磷吸收量，且低磷（0.5 mmol·L-1）处理下的幼苗磷吸收量最高。综上所述，1.0 mmol·L-1磷水平下花榈木幼苗根系形态各指标、根系活力、根中部和根尖分泌的酸性磷酸酶活性和根系分泌的有机酸种类和含量均最大，为本研究中花榈木幼苗生长的最适磷水平。低磷处理（0.5 mmol·L-1）下花榈木幼苗会通过增大根系形态各指标、根系活力、根基和根中部分泌的酸性磷酸酶活性以及有机酸的分泌种类和含量来促进对磷素的吸收，而高磷水平（2.0和4.0 mmol·L-1）并不利于花榈木幼苗根系的生长。本研究为花榈木苗期培养科学施肥以及磷肥的高效利用提供一定理论依据。

关键词: 磷水平, 花榈木, 根系形态, 磷素吸收

Abstract: Phosphorus is one of the essential macronutrient for plant growth and development. Root growth of different plants responds differently to phosphorus levels. Ormosia henryi Hemsl. & E. H. Wilson is a rare and endangered plant species with important economic and ecological values. In this study, we explored the responses of two-year-old O. henryi seedlings to different phosphorus levels. Five phosphorus levels of 0 (P0), 0.5 (P1), 1.0 (P2), 2.0 (P3) and 4.0 (P4) mmol·L-1 were set up with the modified Hoagland nutrient solution. We analyzed the effects of different phosphorus levels on root morphology and phosphorus uptake of O. henryi seedlings. The results showed that: (1) Total root length, total root surface area, total root volume, average root diameter, and root vigor were highest under the P2 treatment and lowest under the P4 treatment. (2) Acid phosphatase activity from root base and middle regions was higher under the P1 treatment, and that from seedling root middle and tip regions was higher under the P2 treatment, which was significantly higher than that of the P0 and high-phosphorus treatments (P3 and P4). (3) The types and total amount of organic acids secreted by the roots were the largest under the P2 treatment, while the types and total amount of organic acids under the P0 and P1 treatments were higher than those under the P3 and P4 treatments. (4) Compared with the P0 treatment, phosphorus application increased the phosphorus uptake of shoots and roots, with the low phosphorus treatment (P1) performed best. In summary, the indicators of root morphology, root activity, acid phosphatase secreted from the middle and tip region of roots, and the type and content of organic acids secreted by roots were all maximized at the phosphorus level of 1.0 mmol·L-1, which was the optimal phosphorus application level for the growth of O. henryi seedlings in this study. Under low P treatment (0.5 mmol·L-1), the uptake of P was promoted by increasing root morphological indices, root activity, acid phosphatase activity secreted from the base and middle region roots, and the types and content of organic acids secreted. However, high phosphorus levels (2.0 and 4.0 mmol·L-1) were not favorable to root growth of Ormosia henryi seedlings. This study provides a theoretical basis for scientific fertilization and efficient utilization of phosphate fertilizer in the seedling stage of O. henryi.

Key words: phosphorus level, Ormosia henryi, root morphology, phosphorus uptake