ROOT ACCLIMATIZATION OF THE MICROPROPAGATED FRUIT TREE ROOTSTOCK 'ADAFUEL' (PRUNUS DULCIS (MILL.) D.A. WEBB × P. PERSICA (L.) BATSCH)
Micropropagated plants undergo acclimatization to adapt to the greenhouse environment. In vitro grown plants have a modified anatomy caused by the in vitro environment. The adaptive capacity of plants (phenotypic plasticity) is based on the modification of their anatomical structure and physiology. This adaptation has been demonstrated in studies dealing with leaf tissues of different species. However, little attention has been paid to root changes and to its capacity to adapt to acclimatization. In this work, changes in roots of in vitro rooted shoots of the almond × peach hybrid rootstock Adafuel (Prunus dulcis × persica) during acclimatization are described using histological and histochemical techniques. Root structure of in vitro rooted shoots was compared with that of acclimatized shoots as well as with that of in vivo rooted shoots that displayed normal anatomy and functioning. Normal roots, grown under in vivo conditions, showed well defined phloem and xylem vessels, endodermis with frequent presence of Casparian strips and phi-thickenings in the cell walls of the cortex close to the endodermis. These characters match with a functional structure able to supply water to the aerial part of the plant and related to a selective nutrient uptake. On the other hand, roots formed in vitro lacked well defined vessels and showed weakly stained Casparian strips and the absence of phi-thickenings, which agrees with a limited water transport. Nevertheless, in vitro formed roots were able to adapt to the new environment and undertake diverse changes during the acclimatization of micropropagated plants.
Marin, J.A., Arbeloa, A., Castillo, M. and Andreu, P. (2009). ROOT ACCLIMATIZATION OF THE MICROPROPAGATED FRUIT TREE ROOTSTOCK 'ADAFUEL' (PRUNUS DULCIS (MILL.) D.A. WEBB × P. PERSICA (L.) BATSCH) . Acta Hortic. 812, 403-408
root anatomy, in vitro culture, histochemistry, exodermis, endodermis, Casparian strips, phi-thickenings