Salt Tolerance in the Halophyte Suaeda maritima (L.) Dum.: Interaction between Aluminium and Salinity

Growth of Suaeda maritima was stimulated by low aluminium concentrationsin saline solution culture with an increase in the number andextent of lateral roots. Under non-saline conditions the sameAl concentrations inhibited growth and led to an abnormal lateralroot initiation. Increasing the level of Al led to growth inhibitionunder both culture conditions. Salinity reduced the uptake of A1 into plant tissue, and therewas no evidence that A1 was tolerated internally. Although short-term³²P influx was increased by A1 there were no long-term effectsof significance on levels of Na, K, Ca nor P in the shoots. The results are discussed in relation to proposed mechanismsof A1 toxicity and the interaction between A1 and salt toxicities.An explanation is proposed for both stimulatory and inhibitoryeffects of A1 as a quantitative expression of a single primaryeffect upon the root system.