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Abstract. Salsinha Y C F, Indradewa D, Purwestri Y A, Rachmawati D. 2020. Selection of drought-tolerant local rice cultivars from East Nusa Tenggara during vegetative stage. Biodiversitas 21: 170-178. East Nusa Tenggara (NTT), with the predominance of dry climate, has the potential of the plant with high tolerance to drought. This research was conducted to select drought-tolerant rice cultivars. There were eight NTT-rice cultivars tested: Pak morin (P1), Mapan (P2), Pak Mutin (P3), Gogo Fatuhao (P4), Seratus-malam Boawae (P5), Padi-Putih Kuatnana (P6), Padi-Putih Maumere (P7) and Gogo Sikka (P8) with 2 control cultivars tested: Ciherang (drought- susceptible) and IR-64 (drought tolerant). The treatment included were 100% FC (control), 50% FC (moderate) and 25% FC (severe drought) during vegetative stage. The morphological analysis of plant (plant height, number of leaves and tillers and root architecture) showed cultivars P1, P5 and P6 possess the best characteristics for tolerating drought. The physiological analysis (plant photosynthetic rate, stomatal conductance, intercellular CO2-concentration, and transpiration rate) showed cultivar P5 and P6 possess the best characteristics for tolerating drought. The high levels of chlorophyll and carotenoid contents during drought conditions were observed in P5, P6, and P7 cultivars. Based on the relative water content, membrane stability index and proline levels, highest-resistance cultivar was P5 and P7 while the cultivar with high sensitivity to drought stress was P3. Based on the morphophysiological characteristics, it can be concluded that P5, P6, and P7 cultivar have the potential as drought-tolerant rice.

Drought is the main abiotic factor that reduces productivity of crops such as rice in the suboptimum area. This study aimed to identify drought-tolerance of local rice cultivars “Nusa Tenggara Timur-Indonesia” through their oxidative defense mechanism. In this study, 17 local rice cultivars and two control cultivars (Ciherang and Situ Bagendit) were used. Drought was imposed by using three levels of FTSW: FTSW 1 (control), 0.5 (moderate drought), and 0.2 (severe drought) during the vegetative stage. Growth parameters such as plant height, number of tillers, number of leaves, and total dry weight were higher in Boawae 100 Malam, Hare Tora, and Padi Putih Kuatnana than other cultivars. The analysis of relative water content, chlorophyll, carotenoid, and proline content also indicated that the Boawae 100 Malam, Gogo Sikka, and Hare Tora cultivar showed a higher result compared to control and other cultivars. Thess characters tend to correlate with the higher activity of antioxidant enzymes in Boawae 100 Malam and Gogo Sikka, when exposed to severe drought conditions. Based on principal component analysis of the physiological changes and enzymatic antioxidant activity, the Gogo Sikka, Boawae 100 Malam, and Hare Tora cultivars were classified as rice cultivars with higher drought tolerance

The effects of exogenously supplied osmoprotectants in crops have not yet been extensively studied. In this study, an osmoprotectant containing a high concentration of proline (2.5 g mol−1 FW) was obtained from a Casuarina equisetifolia leaf extract. The effect of the extract was evaluated in local Indonesian rice cultivars Boawae Seratus Malam (BSM), Gogo Jak (GJ), Situ Bagendit (SB) (drought-tolerant), Kisol Manggarai (KM) and Ciherang (drought-susceptible) cultivars under drought at the morphological, physiological, and genetic levels. Under drought, the KM showed an increased level of OsWRKY, OsNAC, OsDREB1A, and OsDREB2A expression after application of the osmoprotectant, leading to the activation of proline synthesis genes including OsP5CS1, OsP5CR, and OsProDH, while the tolerant cultivars (BSM, GJ, and SB) showed no difference. The content of chlorophyll, carotenoids, anthocyanins, ascorbate peroxidase, catalase, and superoxide dismutase activities also increased in GJ and KM, during drought stress and applied osmoprotectants, but remained low in the BSM. We conclude that the foliar application of osmoprotectants derived from C.equisetifolia caused an accumulation of proline in susceptible plants. The existence of these extracts stabilizes leaf cells and supports photosynthetic compartments and carbon assimilation in plants, leading to growth.

Response by plants to drought occurs through a series of mechanisms that involve transcription regulation. This research was conducted to study transcription factors (TF) and physiological changes in the drought response of local rice cultivars from East Nusa Tenggara (Nusa Tenggara Timur, NTT) during drought stress. Using three NTT local rice cultivars (Boawae Seratus Malam (BSM), Gogo Jak (GJ), and Kisol Manggarai (KM)) and the fraction of transpirable soil water (FTSW) method with two treatment levels, FTSW 1 (control) and FTSW 0.2 (severe stress), we analyzed the TF expression of OsDREB1A, OsDREB2A, OsWRKY45, and OsNAC6. Based on the result, the highest level of TF expression occurred in the BSM, followed by the GJ and KM cultivars. Analysis of physiological characteristics showed an association between TF expression levels and physiological response, with the BSM cultivar showing high pigment levels, high proline content, and lower H2O2 levels. A linkage was also found in relation to water conservation, as indicated by the higher relative water content and cell membrane stability index in the BSM cultivar in contrast to lower electronic leakage and malondialdehyde percentage when exposed to drought. Based on the results, it can be concluded that the BSM cultivar can be considered as a drought‐tolerant local cultivar according to morpho‐physiological analysis. In this study, all NTT local rice cultivars showed a subtle upregulation of stress‐responsive transcription factors OsDREB1A, OsDREB2A, OsWRKY45, and OsNAC6 as responses to drought stress.

Abstract. Putra SP, Santosa, Salsinha YCF. 2023. Waterlogging and salinity stress affecting growth and morphological character changes of Limnocharis flava. Biodiversitas 24: 333-340. Salinity stress and waterlogging affect plant growth response. This study aims to determine the effect of variations in salinity concentration (NaCl) and water depth on the growth and morphological characters of Genjer (Limnocharis flava) plants. The study used a completely randomized design (CRD) with 5 replications with a variable depth of water (W) consisting of W0 = 0 cm from the soil surface, W1 = 5 cm from the soil surface, W2 = 10 cm from the soil surface, and treatment of variations in salt concentration. (NaCl) (S) as many as 4 levels, namely S0 = 0 ppm, S1 = 25 ppm, S2 = 50 ppm and S3 = 75 ppm. Statistical analysis with Analysis of Variance (ANOVA) showed the interaction of high NaCl concentration and higher water depth decreased wet weight, dry weight, height, length and width of leaves of L. flava. The concentration of NaCl significantly affects the growth morphology and anatomy of L. flava. The high concentration of NaCl reduced the wet weight, dry weight, height, length and width of the leaves of L. flava. The high concentration of NaCl causes changes in the anatomical structure of L. flava. Water depth significantly affects the growth morphology and anatomy of L. flava. The higher water depth reduces the wet weight, dry weight, height, length and width of the leaves of L. flava. There is an interaction between NaCl concentration and water depth. The high concentration of NaCl and high level of­­ water depth reduced the wet weight, dry weight, height, length and width of the leaves of L. flava.

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