Bell Lucy E, Moir Jim L, Black Alistair D
Faculty of Agriculture and Life Sciences, Lincoln University, Lincoln 7647, New Zealand.
Plants (Basel). 2024 Aug 15;13(16):2268. doi: 10.3390/plants13162268.
(lotus) and (Russell lupin) persist in the upland grasslands of New Zealand, where soil acidity and associated aluminium (Al) toxicity impede conventional pasture legumes. This experiment investigated the response of lotus and Russell lupin to soil acidity and Al. The species were sown in 20 cm tall 1.2 L pots of acidic upland soil. A mass of 4.5 or 6.7 g lime (CaCO)/L was added to either the top or bottom or both soil horizons (0-9 cm and 9-18 cm), resulting in six treatments across six randomised blocks in a glasshouse. The soil pH was 4.4, 4.9, and 5.4; the exchangeable Al concentrations were 24, 2.5, and 1.5 mg/kg for 0, 4.5, and 6.7 g lime/L. At 16 weeks post-sowing, the plants were divided into shoots and roots at 0-9 cm and 9-18 cm. Root morphology, shoot and root dry matter (DM), shoot nitrogen (N), and nodulation were measured. The total plant DM and shoot-to-root DM ratio were higher, and the shoot %N was lower for the lotus plants than the Russell lupin plants for the various lime rates (13.2 vs. 2.9 g plant, 5.6 vs. 1.6, and 2.4 vs. 3.3%, < 0.05). No response to lime in terms of total DM or total root morphology parameters was exhibited in either species ( > 0.05). Root morphology adjustments in response to acidity between soil horizons were not observed. The results indicated that lotus and Russell lupin are tolerant to high soil acidity (pH 4.4-5.4) and exchangeable Al (1.5-24 mg kg), highlighting their considerable adaptation to grasslands with acidic soils.
百脉根和鲁冰花生长于新西兰的高地草原，那里的土壤酸度及相关铝（Al）毒性阻碍了传统牧草豆科植物的生长。本实验研究了百脉根和鲁冰花对土壤酸度和铝的反应。将这些物种播种在装有酸性高地土壤、高20厘米、容积1.2升的花盆中。在土壤表层（0 - 9厘米）或底层（9 - 18厘米）或两层（0 - 9厘米和9 - 18厘米）添加4.5或6.7克石灰（CaCO₃）/升，在温室中形成六个处理组，分六个随机区组。土壤pH值分别为4.4、4.9和5.4；对于每升添加0、4.5和6.7克石灰的处理，可交换铝浓度分别为24、2.5和1.5毫克/千克。播种后16周，将植物在0 - 9厘米和9 - 18厘米处分为地上部分和根系。测量了根系形态、地上和地下干物质（DM）、地上部氮（N）和结瘤情况。对于不同的石灰施用量，百脉根植株的总植物干物质和地上部与地下部干物质比更高，地上部%N更低（分别为13.2对2.9克/株、5.6对1.6、2.4对3.3%，P < 0.05）。两种植物在总干物质或总根系形态参数方面均未表现出对石灰的反应（P > 0.05）。未观察到不同土层间根系形态对酸度的适应性调整。结果表明，百脉根和鲁冰花对高土壤酸度（pH 4.4 - 5.4）和可交换铝（1.5 - 24毫克/千克）具有耐受性，突出了它们对酸性土壤草原的显著适应性。
