Improvement on rice plant regeneration system from an embryogenic callus using two Malaysian indica rice MR 219 and MR 232 was developed in this study. Different stages of rice explants (zygotic embryos) were tested for callus induction and regeneration using various carbon sources and amino acids. The present study shows that dough stage of zygotic embryos was the best stage of explants for the embryogenic callus induction and regeneration of both rice cultivars. The embryogenic callus nature with the compact structure was confirmed by scanning electron microscopy (SEM) analysis. Inclusion of maltose at the concentration between 10 and 20 mg/L shown higher responsive for the development of green somatic embryos and initiation of rice regeneration with an average of 29-37 (87-91%) regenerated plantlets, respectively. All in vitro regenerated rice plantlets were green, morphological and physiologically healthy condition. Rice plantlets were hardened in acclimatization room for 3 weeks and later transferred into soil with 95% survival in both varieties were recorded. Hence, regeneration system from zygotic rice embryos via somatic embryogenesis system was carried out successfully by using 10 g/L of maltose and combinations of glutamine, asparagine and arginine amino acids.

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The present study describes a direct shoot regeneration-based micropropagation procedure for Vanilla planifolia. Two types of explant (i.e. shoot apex and stem nodal segment) were screened for their shoot induction potential following a three-month treatment with 6-benzylaminopurine (BAP) and -Naphthaleneacetic acid (NAA). Results indicated that the shoot apices were poor candidates for shoot induction whereas the stem nodal segments showed potential for shoot initiation at a rate of up to 6 shoots/explant. Stem nodal segments were the most responsive as shoots formed (55 shoots) directly following treatments with 1 mg/L BAP at half strength MS medium after the third subculture. In addition, more shoots were produced on solid medium treatments compared to the liquid medium treatments in two strengths of mediums tested. Regenerated plantlets derived from the 1 mg/L of BAP treatment were induced to root following a one month culture in growth regulator-free MS medium. There was 90% survival rate of the rooted plantlets after acclimatization in the greenhouse. The findings in the present study would be helpful for large-scale mass propagation of Vanilla planifolia using this simple and efficient protocol.

Callus and suspension cells culture of Kaempferia parviflora was successfully established. Meristematic shoots can be used for utilization of plant cell biosynthetic capabilities for obtaining useful products from valuable medicinal plant to meet out the pharmaceutical demand and also for studying the metabolism.

Preliminary steps in the genetic transformation of indica rice MR219 was investigated in the plant-Agrobacterium tumefaciens interaction. Agrobacterium tumefaciens strain LBA 4404 carrying a binary vector pCAMBIA 1305.2 harboring the modified GUS gene driven by the CaMV 35S promoter was used. Various transformation parameters influences were optimized using embryogenic calli via βglucuronidase (GUS) as a reporter marker. Various transformation parameters were optimized including bacterial concentration, age of embryogenic callus, pre-culture period, wounding technique, cocultivation period, immersion time and dry time before co-cultivation, acetosyringone (AS) concentration, pH of co-cultivation media and temperature of the co-cultivation period. The expression of the transient gusA gene in the plant genome was preliminary confirmed by histochemical GUS assay activity (as blue spots). The results from transient gusA gene expression of calli suggested that the Agrobacterium-mediated transfer system of T-DNA in indica rice MR219 was highly efficient. Therefore, the investigation of factors that influence T-DNA delivery is an important first step in the utilization of Agrobacterium in the transformation of indica rice MR219 calli.

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