红豆树苗木根瘤及其对生长的影响

Root nodule of Ormosia hosiei Hemsl.et Wils.and its Effects on Seedling Growth

红豆树根瘤的形成时间和根瘤的数量与圃地土壤的质量有关,在土壤水肥条件好的环境中,1 a生苗木中的根瘤少见,且根瘤个体极小;在土壤较贫瘠的圃地中,红豆树根瘤十分发达,数量多且形成时间早。红豆树根瘤能够促进苗木生长,有根瘤生长比无根瘤生长的1年生红豆树植株中,根系的干物质增长率46%、根系鲜重的增长率41.9%、茎干物质增长率40.3%、植株总干物质的增长率35.0%、植株总鲜重增长率22.4%、植株叶的干物质增长率14.8%。截根处理有助于根瘤菌感染苗木植株,苗木生长更健壮:截根处理的苗木径高比为4.1%,未截根处理的为3.4%;截根处理促进根系的发育,截根处理的侧根总长度47cm/株、未截根处理的侧根总长度为26cm/株、侧根增加率为80.8%,截根处理的须根总长度228cm/株、未截根处理的侧根总长度为102cm/株、须根增加比率123.5%;截根处理促进苗木根幅的扩大,比未截根处理的根幅增大27.3%。

The quantity and producing time of Ormosia hosiei Hemsl. et Wils. were related to soil conditions in nursery. One-years-old seedlings of Ormosia hosiei Hemsl et Wils. produced more root nodules and earlier in infertile soils compared with in the fertile soils. The root nodule significantly improved growth of Ormosia hosiei Hemsl. et Wils. seedlings. Com- pared with the annum seedlings without root nodules, the dried roots and fresh roots of seedlings with root nodules were in- creased by 46% and 41.9% respectively, the dried stems were increased by 40.3% and the leaves increased by 14.8%. And the dry matter and fresh matter of the whole seedling was increased by 33.0% and 22.4%, respectively. Root-inter- cepting treatment was helpful to nodule bacteria infecting seedlings and improving the seedling growth. The ratio of diameter at basal to height of seedlings in root-intercept treatment was 4.1%, higher than the control （only 3.4% ）. The general length of lateral roots of seedlings in root-Intercepting treatment was 47cm, much greater than that in the control （26cm）. Meanwhile, the fibrous rooi length of seedlings in root-intercepting treatment was 228cm, increased by 123.5% compared with that in the control （102cm）. Root-intercepting treatment could also promote seedling roots expansion and the root width of seedlings in root-intercepting treatment was increased by 27.3% compared with that in the control.