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Accueil du site → Doctorat → Royaume-Uni → 1990 → Micropropagation and micrografting of pistachio (Pistacia vera L. and Pistacia atlantica Desf.)

Imperial College London (1990)

Micropropagation and micrografting of pistachio (Pistacia vera L. and Pistacia atlantica Desf.)

Abousalim, A

Titre : Micropropagation and micrografting of pistachio (Pistacia vera L. and Pistacia atlantica Desf.)

Auteur : Abousalim, A

Université de soutenance : Imperial College London

Grade : Doctor of Philosophy (PhD) 1990

Résumé
In vitro propagation and micrografting techniques of pistachio were developed on two Pistacia species of direct relevance to Morocco ( P. vera and P. atlantica ). Successful in vitro establishment was achieved for seeds of P. vera (98&#37), P. atlantica (89&#37) and nodal explants of actively growing shoots of four-year-old P. vera grafted plants (93&#37). In the case of 30-year-old field-grown P. vera trees, 85&#37 survival of nodal explants was obtained with summer-harvested shoots. However, the subsequent maintenance of cultures was difficult because of a slow decline in growth, increased levels of vitrification and chlorosis. Reduction of apical dominance and stimulation of multiple shoot formation was achieved by culturing P. vera and P. atlantica germinating seeds in the presence of BAP (4 and 0.5 mgl -1 , respectively). In Stage II cultures, MS medium was superior for shoot growth and multiplication but induced faint chlorosis on leaves and callus development at the basis of shoots. BAP at 4 mgl -1 was optimal for multiplication of materials derived from seedlings and four-year-old P. vera . However, vitrification tended to increase with the BAP level used. In the case of explants obtained from P. atlantica seedlings, 1 mgl -1 BAP was optimal. Growth and multiplication were clearly improved by incubating cultures of four-year-old P. vera at 25 o C/16h and were even better at 29 o C/12h as opposed to 19 o C/16h. Shoot-tip necrosis (STN) persisted in cultures of both species at Stages I, II and III. Evidence was obtained that STN was associated with fast growing and low transpiring shoot-tips. The results obtained showed it was most likely to be a calcium- rather than a boron-related physiological disorder aggravated by low vapour pressure deficit in culture vessels. Supplementation of media with calcium gluconate to semi-solid culture media reduced development of STN but did not prevent it. A practical solution to this problem was developed whereby periodic inversion of tubes containing a liquid medium (supplemented with 15 mM Ca gluconate) prevented development of STN in cultures. In Stage III, best rooting of P. vera and P. atlantica seedling on Stage II and previously induced to root (83.3 and 87.5&#37, respectively) on 2 and 1 mgl -1 IBA. Lower rooting responses were obtained for four-year-old-derived shoots of P. vera (50&#37) by a 1000 mgl -1 IBA dip for 10 s. At Stage IV, 81.8&#37 in vitro rooted shoots of P. vera seedling materials were successfully weaned in vivo . Direct rooting of 100&#37 P. vera seedling explants was achieved following a 500 mgl -1 IBA dip for 5 s.

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