Relationship between calcium and agar on vitrification and shoot-tip necrosis of quince (Cydonia oblonga Mill.) shoots in vitro

Abstract

Shoot-tip cultures of Quince C (Cydonia oblonga Mill.) initiated on Murashige & Skoog (MS) medium containing 5 #M BA and 0.6% Phytagar showed both shoot-tip necrosis and severe vitrification. Culturing explants on medium containing 1.2% Phytagar and Ca levels of 3 mM (MS medium), 18 mM and 30mM showed a decrease in growth with increasing medium Ca levels, being especially severe at 30 mM. The Ca content of the explants increased linearly with increasing medium Ca. Culturing explants on medium containing 3 mM, 9 mM, and 18 mM Ca at 0.6, 0.9, and 1.2% agar resulted in reduction in growth, shoot-tip necrosis, and vitrification when either factor was increased. The reduction in shoot-tip necrosis could be accounted for primarily by an increase in medium Ca levels but may also be affected by a change in explant growth. Increasing Ca concentration in the medium resulted in a linear increase in explant K, Ca, Mg, and B levels and a decrease in Mn and Na. Although increasing medium Ca or agar levels reduced vitrification, it is unclear whether they were the direct cause of the reduction in vitrification or whether this response was an effect of the reduction in culture fresh weight.

In vitro Shoot Regeneration and Control of Shoot Tip Necrosis in Tissue Cultures of Soymida febrifuga (Roxb.) A. Juss.

“…Some report that the use of higher concentrations of Ca alleviates or controls the STN (Dyson and Digby 1975, Vieitez et al 1989, Singha et al 1990, Barghchi and Alderson 1996, Piagnani et al 1996, Wang and Van Staden 2001, Chang and Miller 2005, Martin et al 2007). In contrast, other reports show that high Ca concentrations in the culture media significantly increase the percentage of STN (Grigoriadou et al 2000).…”

Micropropagation of Handroanthus heptaphyllus (Vell.) Mattos from seedling explants

“…After 2 weeks of culturing, necrotic apices were observed in shoots growing in semisolid medium provided with either diffused or forced ventilation. This physiological disorder is commonly seen in in vitro cultures affecting a wide range of herbaceous and woody plants (Bairu et al, 2009a) and it is caused by a complex set of factors including plant growth regulators (Bairu et al, 2009b), calcium and boron deficiency (Hepler, 2005;Martin et al, 2007), medium type and salt strength (Jain et al, 2009;Takura and Kanwara, 2011), gelling agent (Singha et al, 1990), aeration (Bairu et al, 2009a), and pH (Pasqua et al, 2002). Our results indicated that the use of liquid medium through a TI system could overcome the shoot tip necrosis of H. heptaphyllus and promote growth and rooting of shoots.…”

Plant regeneration from Crotalaria spectabilis hairy roots which showed inhibited growth of root-knot nematodes (Meloidogyne hapla and M. incognita) in vitro

“…Although shoots could be induced by application of BA, they mostly failed to grow normally due to severe hyperhydricity and callus formation at the base. To avoid the hyperhydricity, it has been recommended to apply some treatments to reduce the water potential such as an elevated concentration of gelling agents (Singha et al 1990;Nugent et al 1991) and forced air ventilation (Wardle et al 1983). Also hyperhydricity was avoided in C. juncea by using medium containing high concentration of gelling agents and using of Milliseal on the plastic cap, which was effective for air ventilation (Ohara et al 2000).…”