Anatomical and nutritional requirements for induction and sustained growth in vitro of Cymodocea nodosa (Ucria) Ascherson

Abstract

In vitro methods of plant micro-propagation are being considered as a possible solution for the decline in seagrass communities registered worldwide. To achieve successful plant micro-propagation, culture conditions are commonly adjusted empirically within almost species-specific conditions, to comply to the following three conditions: (i) culture establishment (ii) shoot production and (iii) rooting and hardening for planting in soil. Cultures of Cymodocea nodosa were established from axenic explants of the apical meristem (approx. 0.5 cm) which regenerated new leaf or produced leaf regenerating calli (5% of cultivated explants) in media containing 10 À6 M of the cytokinin analogue TDZ. Longer ramet explants, not fully axenic, containing internode with leaf and roots were also affected by 10 À6 M cytokinins and auxin type of regulators, as they promoted leaf extension (in cm), particularly GA. None of the explants progressed further to massive shoot propagation and new plantlet production. Instead, experiments made with ramet explants which simulated potential produced plantlet revealed that there seems to be a strong interaction within leaf, rhizome and root, since the carbon fixed in the leaf was rapidly translocated to the rest of the tissue (50% in the roots in a FW basis). The explants preferred ammonium and dihydrogen inorganic phosphate as a nutrient source, efficiently assimilating the former regardless of whether such were added to the underground or surface tissue. However, underground tissue was required to maintain P status in the cultivated explants. #

Plant growth regulators improve the growth and physiology of transplanted Thalassia Hemprichii fragments

“…GA 3 treatment increased the growth rate of seagrass leaves by 41.1% (NRA) and 32.1% (RA), indicating that both treatments were effective in promoting the growth rate of seagrass leaves. This is consistent with the results of previous studies (Balestri and Lardicci, 2006;Garcıá-Jimeńez et al, 2006). However, while IAA and GA 3 accelerated leaf growth, they did not effectively promote an increase in leaf length (Figure 2B).…”

“…For example, research has shown that treating Posidonia oceanica seedlings with a-naphthalene acetic acid and indole-3-butyric acid accelerated root formation and leaf growth (Balestri and Bertini, 2003). Both cytokinins and gibberellin (GA 3 ) can induce leaf and rhizome growth in Cymodocea nodosa explants and can be used either alone or in combination (Balestri and Lardicci, 2006;Garcıá-Jimeńez et al, 2006;Maite et al, 2010).…”

Restoration of Cymodocea nodosa seagrass meadows through seed propagation: germination in vitro, seedling culture and field transplants

“…Culture vessels (Magenta R -G7 300 ml Sigma Co., Chicago, IL, USA) were filled with 40 cc of autoclaved sand and 200 ml of liquid culture medium. We used PES culture medium (Provasoli 1968), but substituted ammonium for nitrate and mono-potassium phosphate for glycerol phosphate, based on previous experience with Cymodocea nodosa explant cultures (see García-Jiménez et al 2006). The salinities of the seawater and culture medium in culture matched ambient seawater (36.6 psu), except where otherwise stated.…”

Stress to microscale of Vallisneria americana by enrichment of nutrients with stoichiometry N:P

“…Estos resultados con la relación N:P del segundo régimen nutricional concuerdan con la vulnerabilidad del ecosistema limnético con pequeños cambios en la carga de nutrientes (Kennish & Paerl, 2010) y con estudios que han indicado la limitada tolerancia de V. americana al estrés salino (Benson et al, 2008). También explica la causa por la cual muchas macrófitas de aguas limnéticas no se ajustan a esquemas convencionales de cultivo in vitro (García-Jiménez et al, 2006;Ruiz-Carrera & Sánchez, 2008;.…”