Glasshouse tomatoes grafted onto Datura stramonium could grow vigorously to 1 metre in height, then suddenly wilt and die. Several experiments under glass in spring, summer and autumn studied the nature of this delayed incompatibility. The results suggested that the wilting was caused by a gradually developing imbalance. To test this hypothesis plants were treated to give different distributions of growth between tomato graft and datura rootstock. Factors investigated were the fruit crop, assimilation surface, light energy, additional shoot development, a 'feeding' tomato shoot with about 8 leaves just above the graft union from which the apex and all other growing organs were removed.It was concluded that if root growth was depressed more or stimulated less than shoot growth, the plant wilted. If root growth was stimulated more than shoot growth, wilting was prevented.Erasmus investigated how increased suction tension influenced wilting in grafted plants grown in nutrient solution. The values for osmotic pressure of the solutions were raised 49 days after planting by different amounts of NaCl. The wilting in fruiting grafted plants was caused by the higher proportion of shoot to root.

Glasshouse tomatoes grafted onto Datura stramonium could grow vigorously to 1 metre in height, then suddenly wilt and die. Several experiments under glass in spring, summer and autumn studied the nature of this delayed incompatibility. The results suggested that the wilting was caused by a gradually developing imbalance. To test this hypothesis plants were treated to give different distributions of growth between tomato graft and datura rootstock. Factors investigated were the fruit crop, assimilation surface, light energy, additional shoot development, a 'feeding' tomato shoot with about 8 leaves just above the graft union from which the apex and all other growing organs were removed.It was concluded that if root growth was depressed more or stimulated less than shoot growth, the plant wilted. If root growth was stimulated more than shoot growth, wilting was prevented.Erasmus investigated how increased suction tension influenced wilting in grafted plants grown in nutrient solution. The values for osmotic pressure of the solutions were raised 49 days after planting by different amounts of NaCl. The wilting in fruiting grafted plants was caused by the higher proportion of shoot to root.