Starch accumulation in the leaves of root-restricted pepper affects plant growth by a feedback-inhibition of the photosynthesis

The mechanism behind the reduced growth occurring in plants subjected to root restriction is still not fully understood. Therefore, this investigation was planned to determine the morphological and physiological changes induced in response to root volume reduction and to determine the time frame within which these changes occurred. In particular, this research focused on the effect of root restriction on growth, leaf gas exchange parameters, carbohydrate production and water relations in pepper (Capsicum annuum L.). Our results show that the reduced growth is mainly linked to a feedback inhibition of the photosynthesis, caused by a concurrent limited stomatal conductance (probably driven by both stomatal factors and hormonal substances) together with a strong accumulation of starch in the leaves.