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  1. Khor, Soo Ping, Rahmad Zakaria, Subramaniam, Sreeramanan
    Trop Life Sci Res, 2016;27(11):139-143.
    MyJurnal
    Throughout the cryopreservation process, plants were exposed to a series of
    abiotic stresses such as desiccation and osmotic pressure due to highly concentrated
    vitrification solution. Abiotic stress stimulates the production of reactive oxygen species
    (ROS) which include hydrogen peroxide, superoxide radicals, and singlet oxygen. Higher
    production of ROS may lead to oxidative stress which contributes to the major injuries in
    cryopreserved explants. Antioxidant enzymes in plant such as ascorbate peroxidase
    (APX) can protect plants from cell damage by scavenging the free radicals. This study was
    determined based on APX enzyme activity of Aranda Broga Blue orchid’s protocorm-like
    bodies (PLBs) in response to PVS2 (Plant Vitrification Solution 2) cryopreservation
    treatments at different stages. PLBs that were precultured at 0.25 M sucrose for 3 days
    were subjected to vitrification cryopreservation method. Results obtained showed that the
    highest APX activity was achieved at PVS2 cryoprotectant treatment prior liquid nitrogen
    (LN) storage. This phenomenon indicating that accumulation of osmotic and dehydrating
    stress throughout the cryopreservation treatment resulted in oxidative burst which in turn
    leads to higher APX activity in order to control the excess production of ROS. To
    conclude, PVS2 treatment was revealed as the most detrimental step throughout
    cryopreservation treatment. Thus, this research also suggested that exogenous
    antioxidant such as ascorbic acid can be added throughout cryopreservation procedure
    especially at PVS2 treatment in the future experiments to aid in regrowth of cryopreserved
    explants by reducing oxidative stress.
  2. Nik Fadzly, Asyraf Mansor, Rahmad Zakaria, Syed Ahmad Edzham
    Sains Malaysiana, 2014;43:973-976.
    Rattans are one of the most unique and economically important plants for most tropical countries. There is however, a lack of interest in the specific study of the rattan spines. In this paper, we tested a new hypothesis concerning the functional role of rattan spines. We proposed that rattan spines also serve as a visual deterrent against herbivores or seed predators. In our proposed method we used an Imaging software, ImageJ, to measure the spine area of four species of rattan (Calamus insignis, Myrialepis schortechinii, Plectocomiopsis geminiflorus and Calamus caesius) from two different orientations (root to shoot and vice versa). Our results showed that rattan spines were very heterogeneous and highly variable between different species. One common trait that the rattan spines share is that spine area measurements of shoot to root (ShR) are larger than root to shoot (RH) orientation. We propose that the downwards spine angle might be specifically designed to discourage climbing leaf and seed predators.
  3. Poobathy, Ranjetta, Rahmad Zakaria, Syed Mohd. Edzham Syed Hamzah, Subramaniam, Sreeramanan
    Trop Life Sci Res, 2016;27(11):15-19.
    MyJurnal
    The terrestrial Ludisia discolor, also referred to as the jewel orchid is prized for
    the quality of its leaves. L. discolor is known as a medicinal herb and is touted for its heatand
    pathogen-resisting qualities. L. discolor is valuable in the production of both flavonoids
    and anthocyanins, antioxidants that are exalted in the health industry. Plant cell cultures
    have emerged as alternative sources of anthocyanin production. Plant protoplast cultures
    are used frequently in transient gene expression studies and in the establishment of callus
    and cell suspension cultures. Benefits of plant protoplast system include similarity to cells
    found in plant tissues, reproduction under controlled conditions, and prevention of masking
    of stress responses to previous handling techniques. A study was conducted to assess the
    amenability of the stem and leaves of L. discolor to protoplast isolation. The stem and leaf
    segments were weighed, sliced into thin layers, immersed in a digestion medium, washed
    and then cultured onto a recovery medium. Results indicated that the production of plant
    protoplasts from L. discolor may be viewed as an alternative in the generation of cell
    cultures and ultimately in the production of anthocyanins from the cell cultures.
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