Loss S P, Robson A D, Ritchie G S
Soil Science and Plant Nutrition, School of Agriculture, University of Western Australia, Nedlands, WA 6009, Australia.
Ann Bot. 1994 Jul;74(1):69-74. doi: 10.1093/aob/74.1.69.
Unlike many plants reported in the literature, lupins do not excrete OH(-) in amounts equivalent to the net excess of inorganic anion uptake over inorganic cation uptake. To investigate the mechanisms involved in the maintenance of charge balance, nutrient uptake and organic anion accumulation of lupins and peas supplied with a range of NO(3)(-) concentrations, were compared. Lupins absorbed less NO(3)(-) than peas on a dry weight basis, which largely ACCOUNTED for the smaller excess of anion uptake over cation uptake in lupins than in peas at the same NO(3)(-) supply. When anion uptake exceeded cation uptake, peas excreted an equivalent charge of OH(-), whereas lupins excreted much smaller amounts of OH(-) than the excess of anion over cation uptake. It was calculated that lupins excreted significant amounts of organic anions when anion uptake exceeded cation uptake, whereas organic anion excretion from peas was negligible, regardless of their NO(3)(-) supply and cation-anion balance. In this study, organic anion excretion was measured from lupin roots grown in near-sterile conditions while supplied with NO(3)(-) at 0, 500 and 2000 microM. Although complete sterility was not achieved, there was close agreement between the organic anion excreted and the excess anion over cation uptake.
与文献中报道的许多植物不同，羽扇豆不会以与无机阴离子吸收量超过无机阳离子吸收量的净过量相当的量来排泄OH(-)。为了研究羽扇豆和豌豆在电荷平衡维持、养分吸收和有机阴离子积累方面的机制，比较了在一系列NO(3)(-)浓度供应下它们的情况。以干重计，羽扇豆吸收的NO(3)(-)比豌豆少，这在很大程度上解释了在相同的NO(3)(-)供应下，羽扇豆比豌豆阴离子吸收量超过阳离子吸收量的过量部分更小的原因。当阴离子吸收量超过阳离子吸收量时，豌豆排泄出等量电荷的OH(-)，而羽扇豆排泄的OH(-)量比阴离子超过阳离子吸收量的过量部分少得多。据计算，当阴离子吸收量超过阳离子吸收量时，羽扇豆会排泄大量有机阴离子，而豌豆的有机阴离子排泄量可以忽略不计，无论其NO(3)(-)供应情况和阳离子-阴离子平衡如何。在本研究中，在近无菌条件下生长的羽扇豆根系在供应0、500和2000 microM的NO(3)(-)时，对有机阴离子排泄进行了测量。尽管没有实现完全无菌，但排泄的有机阴离子与阴离子超过阳离子吸收量的过量部分之间有密切的一致性。
