ROOT CONFINEMENT AFFECTS CANOPY GROWTH, DRY MATTER PARTITIONING, CARBON ASSIMILATION AND FIELD BEHAVIOUR OF OPUNTIA FICUS–INDICA POTTED PLANTS

The objective of this study was to quantify the effect of restricted root volume on canopy and root development and dry matter accumulation in cactus pear Opuntia ficus–indica (L.) Mill.
Measurements of canopy and root development as well as malic acid nocturnal accumulation in the cladodes were taken on plants growing on pots of 3.71, 7.51, 151 and 281. Cuttings of the same size were grown in container over two seasons (30 months) before being transplanted in the field.
The nocturnal accumulation of malic acid, that in CAM species reflects nocturnal CO₂ uptake, was measured routinely in 1-year old cladodes.
Root volume was related to canopy development, and both cladode size and cladode number decreased linearly with container size.
A significative reduction of malic acid nocturnal accumulation in 1-year-old cladodes was measured 4 and 6 months after the plant had been placed in 3.71 containers, and sugar content was also highest in plants growing in the smallest container.
The reduction of root volume was accompained by a substantial increase of root density which was 2–3 times higher for plants in the smallest containers.
The effect of root confinement was still significant after transplanting plants into the field, and vegetative growth and cladode size were still lowest for plants coming from the smallest containers.
One year after field planting, plants from containers were still 2 times larger in canopy volume and produced significantly more fruits than cuttings planted in the field.

XXV International Horticultural Congress, Part 6: Culture Techniques with Special Emphasis on Environmental Implications Physiological Processes in Plants

P. Inglese, L.S. Pace

Cactus pear, propagation

https://doi.org/10.17660/ActaHortic.2000.516.11