EFEK PENYALUTAN KITOSAN TERHADAP KUALITAS PASCA PANEN DAN REGULASI EKSPRESI GEN TERKAIT ROS (REACTIVE OXYGEN SPESIES) PADA TANAMAN HORENZO (Spinacia oleracea)

• Main Author: Pramesti, Yonadita
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/42762
• Institution: Institut Teknologi Bandung

One of the major problems with agriculture in Indonesia is the declining quality of fresh vegetable and fruit commodities due to poor post-harvest management, such as decreased nutritional content and rapid changes in structure and decay. Spinach or Spinacia oleracea is a vegetable that is rich in nutrients and antioxidants, but post-harvest storage and distribution can reduce these nutrients and antioxidants. In general, quality degradation in post-harvest vegetables occurs due to loss of water content in vegetables, microbial activity, and senescent processes. The whole process can increase the production of Reactive Oxygen Species (ROS) which then triggers further damage. Technology that is currently being developed to overcome the problem of spoilage in post-harvest vegetables, one of which is by using environmentally friendly coatings. Chitosan is a by-product of the maritime industry which can be degraded naturally, so it is not toxic to the environment. This makes chitosan an environmentally friendly alternative for use in coating technology. This research was carried out by dipping Horenzo leaves into four treatment solutions namely control treatment (distilled water), acetic acid 1% (v/v), chitosan 0.1%, and chitosan 0.5% (w/v). After that, the leaves are dried and packaged in plastic packages. Spinach was then stored at room temperature for four days and observed every day. Some parameters seen include morphology, reduction in wet weight, accumulation of ROS superoxide and hydrogen peroxide which is carried out by staining with DAB reagent (3,3'-diaminobenzidine) for localization of hydrogen peroxide and staining with NBT (nitro blue formazan) reagent for localization of superoxide. The leaf area that is colored DAB and NBT is then quantified by ImageJ. RNA isolation was also carried out to see the relative expression of ROS-related genes, superoxide dismutase (SOD) and catalase (CAT) to housekeeping gene actin using quantitative RT-PCR or qRT-PCR. SOD and CAT are involved in the degradation of superoxide and hydrogen peroxide in cells. The results showed that 0.1% chitosan coating on Horenzo leaves can reduce the accumulation of superoxide and hydrogen peroxide in plant tissue. Chitosan 0.1% coating can also increase the relative expression of SOD and CAT genes. This shows that the low accumulation of superoxide in the 0.1% chitosan treatment occurs due to high SOD gene expression, whereas the low hydrogen peroxide accumulation in the 0.1% chitosan treatment occurs due to high CAT gene expression. This study concludes that 0.1% of chitosan coating can reduce the accumulation of superoxide and hydrogen peroxide in post-harvest Spinach plants and also can increase the relative expression of SOD and CAT genes in Spinach plants.