Abstract The aim of the present work was to evaluate and analyze the growth and mineral nutrition response of stone pine (Pinus pinea L.) seedlings, an economically important forest species. We ...analyzed the salinity effects on the kinetics of growth, development, and absorption of nutrients of plants cultivated under controlled conditions on a solid organic substrate. Pinus pinea plants were able to tolerate 25 mM NaCl concentration without reduced growth compared to the non-saline control. However, the salt concentration of 50 mM significantly affected the seedling growth after two weeks of treatment. Root growth activity was decreased more than the aerial parts at applied NaCl concentrations. On the other hand, seedlings restricted the transport of Na+ ions to the aerial parts and were strongly selective in favour of K+ ions. The presence of NaCl in the culture medium decreased the absorption rate and the export of K+ and Na+ ions to the aerial parts. This was reflected in the accumulation way of these two ions in the whole plant.
Resumo O objetivo do presente trabalho foi avaliar e analisar a resposta de crescimento e nutrição mineral de mudas de pinheiro-manso (Pinus pinea L.), uma espécie florestal economicamente importante. Analisamos os efeitos da salinidade na cinética de crescimento, desenvolvimento e absorção de nutrientes de plantas cultivadas sob condições controladas em substrato orgânico sólido. As plantas de P. pinea foram capazes de tolerar a concentração de 25 mM de NaCl sem redução do crescimento em comparação com o controle não salino. No entanto, a concentração de sal de 50 mM afetou significativamente o crescimento das plântulas após duas semanas de tratamento. A atividade de crescimento das raízes foi mais reduzida do que as partes aéreas nas concentrações de NaCl aplicadas. Por outro lado, as plântulas restringiram o transporte de íons Na+ para a parte aérea e foram fortemente seletivas em favor dos íons K+. A presença de NaCl no meio de cultura diminuiu a taxa de absorção e a exportação de íons K+ e Na+ para as partes aéreas. Isso se refletiu na forma de acúmulo desses dois íons em toda a planta.
A method is described for producing de novo shoots from internode-derived callus of carnation (Dianthus caryophyllus L.). Plants were regenerated in four steps: callus induction, control of callus ...hyperhydricity, shoot regeneration and root formation. Callus induction occurred on full strength MS medium supplemented with NAA and TDZ. Callus hyperhydricity was avoided using half-strength MS medium. From internode callus, shoot buds obtained on medium containing 0.05 mg/1 NAA with 2 mg/1 BA and 10 mg/1 AgNO₂ needed to be subcultured on 1 mg/1 NAA supplemented MS medium for proliferation. Shoots were rooted on half-strength MS medium with 0.5 mg/1 IBA. Regenerated plants with well-developed root and shoot systems were successfully transferred to field conditions following acclimatization.
In vitro Regeneration of NaCl-adapted Tomato Plants (Lycopersicon esculenteum Mill.). In vitro growth seedlings of tomato (Lycopersicon esculentum Mill. Var. Sabra) were used as source of explants: ...internode segment and leaf fragment. These explants were cultivated into a MS-based medium containing 0.2 mg.l-1ANA and 2 mg.l-1 BAP, supplemented or not with NaCl at 3 and 6 g.l-1 in order to regenerate salt-tolerant plants. Results show that internode's segment and leaf fragment formed callus both in the control and in the saline media (3 and 6 g.l-1). However NaCl affected calli growth and mineral uptake. The callus growth was stimulated by NaCl at 3 g.I-1, but reduced at 6 g.I-1. Na+ and Cl- content of calli increased in saline media with respect to the control. K+ content decreased slightly with salinity, but Ca2+ content did not change. Leaf callus showed higher K+ and Ca2+ contents both in the control and saline media and were more salt tolerant than internodes callus. Latest ones regenerated shoots only on control medium. Leaf callus adapted to 3 g.l-1 NaCl were able to regenerate shoots, but with high percentage of hyperhydricity. Regenerated plants were rooted and acclimatized successfully and they tolerated 3 g.l-1 NaCl added to irrigation solution, when cultivated on peat under glasshouse.
Exploitation of Somaclonal Variability for Research of Carnation (Dianthus caryophyllus L.) Tolerant to Salinity. Callogenesis in carnation (Dianthus caryophyllus L. 'Légion d'Honneur') is possible ...from internodes in a medium containing 0.1 mg.l-1 NAA and 0.1 mg.l-1 TDZ. Regeneration from callus needs 2 mg.l-1 BA. Shoots rooting is obtained on a medium containing 0.5 mg.l-1 IBA. Callus growth is reduced and regeneration rate is very affected in presence of NaCl 100 mM. Shoot rooting is better without NaCl. Regenerated plants present somaclonal variation and those obtained under salt stress have a better relative tolerance to salinity than plants regenerated without salt.
Plusieurs paramètres phénologiques et physiologiques ont été étudiés, chez 9 variétés de céréales cultivées sous des conditions de déficit hydrique. En prenant le rendement en grains comme ...indicateur, les résultats ont montré que, la résistance à la sécheresse est liée à la capacité d'une variété de développer un nombre élevé de mécanismes d'adaptation et non pas à la présence d'un mécanisme donné
