Effect of exogenous ABA on somatic embryo maturation and germination in Persian walnut (Juglans regia L.)

Abstract

Low efficiency of embryo maturation, germination and conversion to plantlets is a major problem in many species including Persian walnut. We studied the effects of abscisic acid (ABA) and sucrose, on the maturation and germination of Persian walnut (Juglans regia) somatic embryos. Individual globular somatic embryos were grown on a maturation medium supplemented with different combinations of ABA and sucrose for ca. 1 month, until shoot meristems and radicles had developed. White and opaque embryos in late cotyledonary stage were subjected to desiccation after the culture period on maturation media. The number of germinated somatic embryos was influenced by the concentrations of ABA in the maturation medium. The best treatment for germination, in which both shoot and root were developed contained 2 mg l -1 ABA and resulted in 41% conversion of embryos into plantlets. Regeneration was reduced at higher levels of ABA. While ABA always reduced the rate of secondary embryogenesis, treatments containing 4.0% sucrose significantly increased the number of secondary embryos. On the other hand, sucrose had little influence on maturation. Normal and abnormal embryos were verified anatomically.

Polyethylene glycol effects on somatic embryogenesis of papaya hybrid UENF/CALIMAN 01 seeds

“…Maturation is a crucial phase in the somatic embryogenesis process, in which the addition of maturation promoters, such as PEG (KeinonenMetta et al 1996, Vooková and Kormuták 2002, Langhansov et al 2004, Maruyama and Hosoi 2007, Krajnakova et al 2009, Calic-Dragosavac et al 2010, abscisic acid (ABA) (Find 1997, Vahdati et al 2008, Calic-Dragosavac et al 2010, Anandam et al 2012, maltose (Li et al 1998) and activated charcoal (Krajnakova et al 2009, Calic-Dragosavac et al 2010, is crucial to promote the maturation of somatic embryos and conversion into plantlets.…”

Improvement of in vitro embryo maturation, plantlet regeneration and transformation efficiency from alfalfa (Medicago sativa L.) somatic embryos using Cuscuta campestris extract

“…4 Chromatogram of HPLC on total ABA extracted from the C. campestris Fig. 5 Comparison of antibacterial activity of C. campestris extracts against Agrobacterium tumefaciens, using the agar well diffusion method (Vahdati et al 2008;Rai et al 2011). Exogenous ABA regulates synthesis of storage proteins in somatic embryos and inhibits the precocious germination of somatic embryos.…”

“…Since somatic embryos lack endosperm, which is a source of plant regulators and nutrients, providing natural plant regulators and nutrients in the culture medium could be helpful to somatic embryos. Abscisic acid improves the somatic embryo maturation and their development into normal plantlets (Vahdati et al 2008). Culture medium can be enriched with natural organic extracts which has amino acids, vitamins and some plant regulators that can promote plant growth, regeneration and somatic embryogenesis.…”

Endogenous Quantification of Abscisic Acid and Indole-3-Acetic Acid in Somatic and Zigotic Embryos of Nothofagus alpina (Poepp. & Endl.) Oerst

“…The main problem in the somatic embryogenesis process is the efficient maturation of the embryos, in general, somatic embryo germination is altered by culture conditions (embryo induction and maturation); therefore, it generally results in different degrees of development (germination) and plantlet development (Vahdati et al, 2008). Therefore, it is necessary to apply maturation treatments in order to maximize the development of embryos in later stages (Corredoira et al, 2003;Miguel et al, 2004).…”

“…ABA had a positive effect in the control of SSE in Quercus suber L. (García-Martín et al, 2005) and plays a role in the accumulation of reserve substances (Gupta and Grob, 1995). ABA has been recognized as a factor for promotion of normal development and maturation of somatic embryos and their uniformity in Quercus ilex L. and Juglans regia L. (Mauri and Manzanera, 2003;Vahdati et al, 2008). Studies show a decrease in fresh weight (FW) and SSE in treatments where ABA was added can be explained by a possible osmotic besides the effect and ABA's capability to inhibit premature germination and control SSE (Bentsink and Koornneef, 2008;Manoj et al, 2008) ABA plays a fundamental role in both somatic embryogenesis and zygotic embryogenesis.…”