Tomato (Lycopersicon esculentum Mill., cv. 'Better Bush') Plant Response to Root Restriction

Publisher Website
Google Scholar
Abstract
Our earlier observations of root-restricted tomato plants indicated that alterations in plant morphology occurred from day 18 to 32 of a 46 d culture period. Here, root-respiration capacity and root-ethylene production were measured to determine if these parameters were correlated with the observed changes in plant morphology. Plants were cultured in a flow-through hydroponic system. Roots in large containers (1500 cm 3 , control), exhibited a gradual decline in respiration capacities, from 9009 to 2147 mm 3 O 2 g -1 (DW) h -1 . A significant decline in respiration capacity was observed for roots grown in small containers (25 cm 3 , root-restriction treatment) after 18 d in culture. Once treated root systems attained a maximum weight (c. 1.59 g DW), their respiration capacity remained relatively constant (c. 1212 mm 3 O 2 g –1 (DW) h –1 ). The observed change in root respiration, for the restricted plants, was closely correlated with alterations in root:shoot ratio. We conclude that the decline in root respiration capacity represents a significant indicator of reduced root metabolism. Thus, root energetics plays a role that influences the growth habit of root-restricted plants. Slight increases in ethylene production were observed for treated roots on days 22, 25 and 30. This increase in production appeared at a time when adventitious rooting was initiated. Overall, control and treated roots produced ethylene within a range of 61 to 10.2 mm 3 kg -1 (FW) h -1 . Preliminary sampling of leaf tissues suggests that ethylene production rates did not differ for mature leaves of the two plant groups.

This publication has 0 references indexed in Scilit: