Iron toxicity stress causes physiological and metabolic changes in rice and other plants. To date, there is little information about the metabolite profile of rice under Fe toxicity conditions. In fact, metabolite has a contribution to the physiological condition of plants. Plant metabolomics is a study of low-molecular weight metabolites in plants under certain conditions. The objective of the research was to investigate physiological and metabolic changes in rice under Fe toxicity stress. Two-week-old seedlings of four rice varieties with various Fe toxicity tolerance levels were stressed hydroponically with 400 ppm FeSO 4. 7H 2 O for 10 d. Numerous physiological characters were observed and untargeted metabolomic analysis was carried out using gas chromatography-mass spectrophotometry (GC-MS). The results showed Fe toxicity induced physiological and metabolite variation in rice. By comparing the metabolites synthesized in Fe toxicity-stressed plants with control plants, it showed that elaidic acid, linoleic acid, and linolenic acid could be as metabolite marker candidates for rice response to Fe toxicity stress. When plants exposed to Fe toxicity stress, elaidic acid increased, whereas linoleic-and linolenic acid decreased. The alteration of fatty acid composition in the root and shoot suggests the alteration of metabolites is one of the tolerance strategies of rice to Fe toxicity stress. This finding offers an insight about the tolerance strategies of rice under Fe toxicity stress related to the maintenance process of the cell membranes during this stress. The genes underlying biosynthesis of the fatty acid could be a target of future research on responsible genes for Fe toxicity tolerance in rice.

Drought is one of the limiting factors in crop cultivation, such as in oil palm (Elaeis guineensis Jacq.). The transgenic approaches are expected to increase plant tolerance to drought stress and minimize low productivity when drought occurs. Proline is an osmoprotectant compound in plants which its biosynthesis involved the P5CS gene. The objective of this study was to evaluate the tolerance level of P5CS-transgenic oil palm to drought stress induced by polyethylene glycol 6000 (PEG-6000). In this present study, the transgenic and non-transgenic oil palms were treated by  0, 2, and 4% PEG-6000 under in vitro conditions. The experiment was arranged as a factorial completely randomized design with three replications. The drought level score, total chlorophyll content, carotenoids, and proline content, as well as P5CS gene expression in leaf tissues were observed at 7 and 14 days after stress treatments. The result showed that transgenic plantlets had a lower drought level score than those of non-transgenic lines. A concentration of 4% PEG-6000 treatment reduced the total chlorophyll and carotenoids contents than that of 2% concentration in non-transgenic plantlets at 7 and 14 day after treatments (DAT). In addition, proline content and P5CS gene expression level in transgenic had been significantly increased during stress treatment. Based on these results, it can be concluded that the P5CS transgene increased the drought stress tolerance of oil palm.

No abstract

Efek negatif yang ditimbulkan oleh pestisida kimia terhadap ekosistem dan lingkungan mendorong usaha untuk menekan penggunaannya, salah satunya melalui penggunaan biopestisida nabati. Sebagai salah satu hama penting tanaman pertanian, ulat grayak (Spodoptera litura) perlu untuk ditekan populasinya untuk meminimalisir kehilangan hasil panen. Salah satu tanaman yang dapat dimanfaatkan sebagai biopestisida nabati untuk mengendalikan hama ulat grayak yaitu Cerbera odollam. Penelitian ini bertujuan untuk mengetahui potensi biopestisida nabati daun bintaro terhadap waktu berhenti makan (stop feeding) dan mortalitas larva ulat grayak. Penelitian ini didesain menggunakan rancangan acak lengkap yang terdiri dari enam taraf perlakuan (0 (kontrol), 10, 15, 20, 25, dan 30 g/L) dan masing-masing perlakuan diulang tiga kali. Ekstrak diaplikasikan ke larva ulat grayak dengan menggunakan metode leaf dipping methods. Efektivitas pengaruh ekstrak daun bintaro terhadap ulat grayak dilakukan dengan mengamati waktu berhenti makan (time of stop feeding) dan mortalitas (tingkat kematian larva). Hasil penelitian menunjukkan bahwa ekstrak daun bintaro berpotensi digunakan sebagai biopestisida nabati untuk larva S. litura. Mortalitas larva S. litura semakin meningkat sejalan dengan semakin lamanya waktu aplikasi ekstrak. Selain itu, mortalitas larva ulat grayak tertinggi terjadi pada perlakuan 20, 25, dan 30 g/L yaitu sebesar 40% pada 168 jam setelah aplikasi.

No abstract