Kidd P S, Proctor J
Department of Biological Sciences, University of Stirling, Stirling FK9 4LA, Scotland, UK.
J Exp Bot. 2000 Jun;51(347):1057-66. doi: 10.1093/jexbot/51.347.1057.
Aluminium (Al) is rhizotoxic and is often present in acidic soils at activities high enough to inhibit root elongation. The objectives of the present study were to assess the level of Al tolerance in different races of Betula pendula Roth (Silver Birch) and to investigate how growth and nutrient acquisition were affected by Al. A solution culture technique was employed which simulated natural soil solutions. Aluminium at low concentrations (2 and 5 mg l(-1)), enhanced the growth of two races of B. pendula originating from soils poor in Al (FM and KP). In contrast, Al, at all concentrations tested, inhibited growth in an Al-sensitive race (KR) whose provenance was a calcareous soil. At concentrations >/=10 mg l(-1), Al reduced growth in FM and KP races, while growth increased with increasing Al (up to 25 mg l(-1)) in the Al-tolerant, SMM, race. Aluminium altered both root and leaf architecture. Low Al concentrations (<5 mg l(-1)) significantly increased leaf expansion, and high concentrations (>25 mg l(-1)) reduced leaf expansion. In the Al-sensitive race, KR, there was a loss of apical dominance, and both lateral and primary roots were stunted and swollen, with increasing Al concentrations. These results demonstrated pronounced racial differences in tolerance to Al by B. pendula that could be predicted from the soil environment of each race.
铝（Al）具有根毒性，在酸性土壤中常以足以抑制根系伸长的活性水平存在。本研究的目的是评估不同种源欧洲白桦（Betula pendula Roth）对铝的耐受水平，并研究铝对其生长和养分获取的影响。采用了模拟天然土壤溶液的溶液培养技术。低浓度（2和5毫克/升）的铝促进了源自低铝土壤的两个欧洲白桦种源（FM和KP）的生长。相反，在所有测试浓度下，铝抑制了来自钙质土壤的铝敏感种源（KR）的生长。在浓度≥10毫克/升时，铝降低了FM和KP种源的生长，而在耐铝的SMM种源中，生长随着铝浓度增加（高达25毫克/升）而增加。铝改变了根和叶的形态结构。低铝浓度（<5毫克/升）显著增加叶片扩展，高浓度（>25毫克/升）则降低叶片扩展。在铝敏感种源KR中，随着铝浓度增加，顶端优势丧失，侧根和主根发育不良且肿胀。这些结果表明欧洲白桦对铝的耐受性存在明显的种源差异，这可以从每个种源的土壤环境中预测出来。
