Growth Of Rice Plants Research Articles

Identifikasi Perubahan Iklim dan Korelasinya terhadap Produksi Tanaman Padi (Oryza sativa L.) di Kabupaten Karawang

Rice is a food crop that is widely consumed by Indonesian people. Water availability and environmental conditions greatly influence the growth of rice plants, so that climate change can affect the production and productivity of rice plants. Efforts to anticipate a decline in rice production and productivity due to climate change require a study by identifying climate variabels, analyzing the correlation between climate and rice plants, and identifying solutions to adapt to climate change. The research was conducted in Karawang Regency using quantitative-descriptive methods, with the data analyzed being climate variabels including rainfall, temperature, humidity from 1991-2022 and rice plant variabels including rice production and productivity from 1991-2022. The analysis was carried out using trend analysis, correlation, regression, auto-regressive integrated moving average methods, and farmer interviews as analyses of adaptation strategies. The results of the research show that climate change has occurred in Karawang Regency as indicated by a decrease in rainfall intensity of 41.84 mm, a decrease in humidity percentage of 4.69%, and an increase in temperature of 〖0,92 〗^o C, and the climate type according to Oldeman is type D2, or there is no change in Oldeman’s Agroclimate zone. The results of interviews for adaptations include rotating crop planting, managing planting time, using seeds that are resistant to pest attacks, paying attention to the type of fertilizer used, controlling pests using insecticides or natural predators, and pumping water for irrigation channels.

OsPP2C49, a Negative Regulatory Factor in the Abscisic Acid Signaling Pathway, Positively Regulates Grain Yield in Rice

Clade A type 2C protein phosphatases (PP2Cs) are crucial components of the abscisic acid (ABA) signaling pathway. Research on clade A PP2Cs has focused more on their roles related to ABA signaling and stress responses than on the molecular mechanisms mediating their effects on plant growth and grain yield. Rice (Oryza sativa L.) is an important food crop worldwide. We previously determined that OsPP2C49, which encodes a rice clade A PP2C family member, negatively controls rice responses to drought, salt, and high-temperature stresses. In this study, we investigated the regulatory effects of OsPP2C49 on ABA responses and rice grain yield. By analyzing potential interactions with core ABA components, including pyrabactin resistance 1 (PYR1)/PYR1-like (PYL)/regulatory component of the ABA receptor (RCAR) and stress-activated protein kinases (SAPKs), we confirmed that OsPP2C49 is involved in the ABA signaling pathway. OsPP2C49 overexpression led to decreased ABA sensitivity and increased rice grain yield; the opposite phenotypes were observed in the ospp2c49 knockout mutants. Therefore, OsPP2C49 negatively regulates ABA responses, but positively modulates rice grain yield. Furthermore, we found that OsPP2C49 can interact with and dephosphorylate five OsSAPKs in vitro. Unlike OsPP2C49, these OsSAPKs positively modulate ABA responsiveness, but negatively affect rice yield. These findings indicate that OsPP2C49 may partially regulate ABA responses and rice grain production by dephosphorylating OsSAPKs. This study preliminarily explored the molecular basis of the regulatory effects of OsPP2C49 on rice plant growth and grain yield.

Cavalcade Legume (Centrosema pascuorum) Used as Soil Amendment in RD41 Rice Fields: Short-term Effects on the Soil Nematode Community, Soil Properties, and Yield Components

Numerous phytoparasitic nematodes have been identified in Thailand’s paddy fields, which routinely cause substantial reductions in rice crop yields. However, effective strategies for their management have yet to be documented. In this study, cavalcade legume was used as a soil amendment in RD41 rice fields to examine its effects on the soil nematode community, soil properties, and yield components compared to untreated control plots. The results demonstrated that the population densities of plant-parasitic nematodes (PPNs) in the order Tylenchida, primarily Hirschmanniella sp., significantly decreased in cavalcade-treated plots across all soil sampling periods. Moreover, there was an increase in the populations of beneficial nematodes within the orders Dorylaimida and Araeolaimida. In contrast, greater PPN populations were observed in the control plots compared to the initial nematode population. In addition to reducing PPN populations, this legume showed other benefits, specifically increased soil properties (available P) and rice plant growth (plant height and number of tillers). While there was no statistically significant difference in soil organic matter (SOM) content, the application of this legume tended to increase SOM content, in contrast to a decrease in SOM content observed in the control plots. Overall, this study provides valuable insights into the substantial advantages of using cavalcade legumes in RD41 rice fields.

Mechanistic insight into interactive effect of microplastics and arsenic on growth of rice (Oryza sativa L.) and soil health indicators

Microplastics (MPs) pollution has recently become a major concern for agroecosystems. The interplay between MPs, and heavy metal(loid)s in the soil can intensify the risks to plant growth and human health. The current study investigated the interactive effects of arsenic (As) and biodegradable and petroleum-based conventional MPs on rice growth, As bioavailability, soil bacterial communities, and soil enzyme activities. As-contaminated soil (5 mg kg−1) was treated with conventional MPs i.e., polystyrene (PS) and polyethylene (PE) and biodegradable MPs i.e., polylactic acid (PLA) and polybutylene adipate terephthalate (PBAT) at 0.1 % and 1 % rates. In a pot experiment, rice plants were cultivated in soil co-contaminated with As and MPs. PLA-MPs exhibited significant interactions with As, increasing its bioavailability and impairing rice plant growth by enhancing plant oxidative stress. The results illustrated that T2 treatment (PLA-MPs @ 1 % + As 5 mg kg−1) significantly decreased the root and shoot lengths, root and shoot dry weights as well as the rates of photosynthesis, transpiration, intercellular CO2, and stomatal conductance in rice plants. Biodegradable PLA-MPs @ 1 % resulted in increased uptake of As in rice roots, stems, and leaves by 13.4 %, 38.9 %, and 20.6 %, respectively. In contrast, conventional PE-MPs @ 1 % showed contradictory results with As uptake declined by 2.2 %, 5.1 %, and 9.9 % in rice roots, stem and leaves. Soil enzyme kinetics showed that biodegradable MPs increased the activities of soil catalase, dehydrogenase, and phytase enzymes, whereas both conventional PS and PE-MPs decreased their activities. Moreover, As and PLA-MPs combined stress altered soil bacterial communities by increasing the relative abundance of Protobacteria, Acidobacteria, Chloroflexi, and Firmicutes phyla by 49 %, 29 %, 82 %, and 57 %, respectively. This study provides new insights into MPs-As interactions in soil-plant system and ecological risks associated with their coexistence.

Interaction Effects of Phosphorus and Zinc Application on Their Availability and Growth of Rice (<em>Oryza sativa</em>) in an Alfisol of Sri Lanka

This study investigated the interactive effects of phosphorus (P) and zinc (Zn) application on P and Zn availability, and growth of rice (Oryza sativa) in an Alfisol. In a laboratory incubation experiment, soil samples were supersaturated with treatment solutions with all possible combinations of four P levels (0, 6, 12, and 24 mg kg-1 equivalent to 0, 10, 20, and 40 kg ha-1, respectively) and three Zn levels (0, 1.2, and 2.4 mg kg-1 equivalent to 0, 2, and 4 kg ha-1, respectively), and then allowed to air-dry. Available P and Zn contents in soil increased as the application rates were increased but P×Zn rate interaction effect was not significant. In a pot experiment, rice (var Bg 358) was grown for 10 weeks with all possible combinations of three P levels (0, 5.5, and 16.5 mg kg-1) and three Zn levels (0, 1, and 2 mg kg-1). Initial soil P was higher than the critical level (12 mg kg-1), but available Zn was below the critical level (1.5 mg kg-1). The main effect of P rate did not significantly affect the number of tillers and shoot dry matter content while Zn application decreased them. Root dry matter, and root and shoot P concentrations were significantly (P<0.05) influenced by P×Zn rate interaction effect. While, plant P uptake was significantly decreased due to P and Zn application, plant Zn uptake was not affected. Therefore, for a better growth of rice plant, the soils with high available P and low Zn contents should be carefully fertilized with P and Zn fertilizers.

Municipal-treated wastewater as a practical alternative to conventional rice irrigation: Effects on antibiotic resistance genes, virulence factors and human bacterial pathogens in soil, and responses of rice grain quality

Reuse of municipal-treated wastewater for agricultural irrigation is becoming increasingly prevalent due to growing demand and decline in freshwater supplies. However, the microbial contamination profile, including antibiotic resistance genes (ARGs), virulence factors (VFs), and human bacterial pathogens (HBPs) in agricultural soil irrigated with municipal-treated wastewater for paddy cultivation, was unknown. Here, metagenomic analysis was applied to provide a systematic insight into the resistome, VFs and HBPs in paddy soils irrigated with municipal-treated wastewater. The obtained results revealed that the residual antibiotics in municipal-treated wastewater has an impact on the antibiotic resistome by increasing both the total number and abundance of ARGs. Furthermore, it was found that sul1 could serve as a potential risk indicator for assessing ARG contamination. VFs, core HBP abundance, and dangerous pathogens remain unaffected by municipal-treated wastewater irrigation for paddy. The good coexistence patterns of ARGs-HBPs and ARGs-VFs demonstrated the presence of resistant pathogenic bacteria. The network analysis revealed that ARGs-bearing Legionella pneumophila, Mycobacterium marinum, Bordetella pertussis, Staphylococcus aureus, and Pseudomonas aeruginosa might be ranked as high-risk HBPs. Additionally, our investigation also demonstrated that reuse of municipal-treated wastewater for agricultural irrigation had no detrimental effects on rice plant growth and grain quality. This study was the first to investigate the response of VFs and HBPs in paddy soil under long-term municipal-treated wastewater irrigation. The obtained results provide a scientific basis for the safe application of municipal-treated wastewater.

Analysis of the Application of Vitamin B1 on the Response of Salinity Stress Resistance in Several Varieties of Rice (Oryza Sativa L.)

One of the most common stresses in rice cultivation is salinity. Rice plants stressed by salinity exhibit changes such as yellowing leaves, drying tips, and chlorosis. The efforts made by the government and farmers so far include implementing cultivation scheduling techniques, planting patterns, and using stress-resistant varieties, as well as improving soil to increase water-holding capacity through lime application. Each of these efforts comes with its own risks. Another approach to enhance the growth and yield of rice plants is the application of vitamins. Providing vitamins can stimulate the growth of plant organs, as they play a crucial role in the growth process by acting as catalysts for metabolism. Research has indicated that vitamin B1 can significantly promote plant growth under stressful conditions. This study aims to investigate the positive effects of various concentrations of vitamin B1 on the growth and yield of rice plants while also reducing salinity stress. The method used involved planting three varieties of rice—IR-46, Inpari-32, and Pokkali—in planting buckets using the TABELA system. Vitamin B1 was applied at concentrations of 0, 5, and 10 mM during the peak vegetative phase, with salinity stress of 6 dS/m introduced one day after vitamin application. The plants were maintained under salinity stress conditions until harvest, during which morphological and phytochemical analyses were conducted. Morphological analysis included measurements of plant height, number of tillers, number of productive tillers, number of grains per panicle, and percentage of healthy grains. Biochemical parameters measured included total chlorophyll and electrolyte leakage analysis. The results indicate that vitamin B1 can effectively reduce stress in plants affected by salinity.

Pertumbuhan dan Produksi Padi (Oryza sativa L) Menggunakan Berbagai Sistem Tanam Pada Varietas Yang Berbeda

Rice is the most important food crop in Indonesia. Indonesian people use rice as a daily staple, because rice contains a source of carbohydrates and energy. The aim of the research is to determine the planting systems, varieties and interactions between planting systems and varieties that provide the highest growth and production in rice plants. This research uses a 2 factor factorial design, the first factor is the planting system (S) which consists of 3 treatments: 20 x 20 cm tile planting system (S1), 25 x 25 cm tile planting system (S2), and legowo planting system 2 :1 (S3), the second factor is Variety (V) which consists of 2 treatments, namely the Ciherang Variety (V1) and the Mekongga Variety (V2). The observation parameters are plant height, number of tillers, number of productive tillers, number of perennial seeds, weight of permalai seeds, weight of 1000 grains, and weight of grain per unit. The research results showed that the Jajar Legowo 2:1 planting system gave the highest average number of tillers, namely 24.8 stems, and the highest number of productive saplings with an average of 18.9 stems. The Ciherang variety has a higher plant height and number of perennial seeds than the Mekongga variety. There is no interaction between planting system and variety.

Strigolactone Alleviates NaCl Stress by Regulating Antioxidant Capacity and Hormone Levels in Rice (Oryza sativa L.) Seedlings

Salt stress is a key environmental factor altering rice plant growth. Strigolactones (GR24) play a vital role in responding to various abiotic stresses and regulating plant growth. However, the regulatory mechanisms of SLs on rice seedlings under salt stress have not yet been clarified. A pot experiment was undertaken to evaluate the effects of GR24 soaking on the rice variety ‘Huanghuazhan’ (salt-sensitive) seedling growth, antioxidant metabolism, and endogenous hormones under NaCl stress. Results showed that NaCl stress significantly inhibited rice growth; disrupted antioxidant enzymes activity; and increased the content of soluble proteins (SPs), proline (Pro), malondialdehyde (MDA) and hydrogen–peroxide (H2O2). GR24 significantly improved photosynthetic pigments and antioxidant–enzyme activities, including superoxide dismutase (SOD), catalase (CAT), peroxidase (POD), and ascorbate–peroxidase (APX); increased SP, ascorbic acid (AsA); and reduced glutathione (GSH) content and MDA, H2O2, and Pro content, resulting in the mitigation of oxidative injury caused by NaCl stress. Moreover, GR24 significantly increased the content of strigolactones (SLs), cytokinin (CTK), auxin (IAA), Gibberellin A3 (GA3), and IAA/ABA and CTK/ABA ratios and decreased the abscisic acid (ABA). Findings indicated that GR24 alleviated oxidative damage caused by NaCl stress by increasing photosynthetic and antioxidant capacity and maintaining the balance of endogenous hormones, thus improving the salt tolerance of rice seedlings.

Endophytic Bacteria From Banana Plants Improves The Growth of Rice (Oryza sativa) and Maize Plants (Zea mays)

AbstractFive isolates of endophytic bacteria from the roots of klutuk and ambon banana plants produce indole acetic acid (IAA) hormone. However, the evidence of its potential as Plant Growth Promoting Bacteria (PGPB) has not been observed. Therefore, this study aims to determine the effect of bacterial isolate to increase the growth of rice and maize plants. The growth rates of bacterial isolates were measured before the inoculation into the plant root. The root inoculation was performed following a complete randomized design. Root inoculation was carried out using 5 isolates of endophytic bacteria in rice and maize plant seedlings, and the process was repeated 15 times (n=15). The growth of rice and maize plants was monitored from 1st day after planting (dap) to the 14th dap. The collected data were analyzed by student t-test with a significant level of 5% (a= 0.05). The results showed that the logarithmic phase of all isolates was reached at 4 to 16 hours and K10, K25, K35, K111, and A41 isolates increased the height of plants while the K111 isolate can significantly increase the plant height compared to the control. This experiment revealed that the endophytic bacteria from banana plants increase the rice and maize plant’s growth.AbstrakLima isolat bakteri menghasilkan hormon indole acetic acid (IAA) yang berpotensi memacu pertumbuhan tanaman. Namun, bukti empiris potensinya sebagai Plant Growth Promoter Bacteria (PGPB) belum didapatkan. Penelitian ini bertujuan untuk mengetahui pengaruh isolat bakteri terhadap peningkatan pertumbuhan padi dan jagung. Penelitian ini menggunakan metode eksperimen dengan desain rancangan acak lengkap dan setiap perlakuan diulang 15 kali (n= 15). Hasil pertumbuhan tanaman yang diinokulasi dengan isolat bakteri masing-masing dibandingkan dengan perlakuan kontrol. Sebelum perlakuan, tingkat pertumbuhan bakteri endofit diukur sehingga didapatkan fase logaritmik yang cocok untuk dilakukan inokulasi ke akar tanaman. Setelah perlakuan, pertumbuhan tanaman padi dan jagung dipantau dari hari ke-1 setelah tanam (hat) sampai dengan ke-14 hat. Data dianalisis dengan uji t dengan taraf signifikan 5% (α= 0,05). Hasil penelitian menunjukkan bahwa 5 isolat yang berasal dari tanaman pisang mengalami fase logaritmik pada masa inkubasi 4 hingga 16 jam dan semua isolat bakteri meningkatkan tinggi tanaman serta isolat K111 dapat meningkatkan tinggi tanaman secara signifikan dibandingkan dengan kontrol. Penelitian ini mengungkapkan kemampuan bakteri endofit dari tanaman pisang untuk meningkatkan pertumbuhan tanaman.

Excess supply of sulfur mitigates thallium toxicity to rice (Oryza sativa L.) growth in hydroponic experiment

Sulfur (S) is an essential element for the growth of rice plants (Oryza sativa L.), crucial for enhancing crop yield and grain quality. However, its potential in mitigating thallium (Tl) toxicity in rice remains unclear. In this study, a hydroponic experiment was performed to investigate the effects of low, medium and high S application levels (LS, MS, HS) on Tl accumulation in rice at three Tl exposure levels (0, 0.5 and 1 mg·L−1). Our findings reveal that the exogenous S application could alleviate Tl toxicity, enhancing fresh weight and shoot length of rice plant. Additionally, HS (HS, SO42− content was 387.84 mg·L−1) group significantly increased chlorophyll and glutathione (GSH) content by 6.46 to 21.38 % and 2.15 to 7.31 % respectively, while reducing malondialdehyde (MDA) levels by 17.43 to 28.48 %, compared to MS (MS, SO42− content was 193.41 mg·L−1) group. Fe content in rice roots and iron plaque consistently increased with S provision under Tl-free and Tl-contaminated conditions. In Tl exposure environment, HS and LS (LS, SO42− content was 1.02 mg·L−1) groups exhibited significant differences in Fe contents and iron plaque in rice root. Moreover, in Tl exposure environment, S application reduced Tl concentration in iron plaque, root, and shoot, HS treatment showed Tl content reduction from 16.29 % to 25.89 %, compared to LS treatment. Our findings underscore the potential of S application in hydroponic environment to promote rice growth and mitigate Tl accumulation, offering insights for developing effective Tl remediation strategies by using S-contained fertilizers.

Impact of 240 g/L glyphosate IPA on weed control and upland rice (Oryza sativa L.) growth and yield in a no-tillage system

Glyphosate IPA 240 g/L herbicide is known as one of the effective chemical solutions in weed control, especially in no-tillage systems. No-tillage systems offer advantages in upland rice cultivation by reducing soil damage and production costs. However, the main challenge in the application of no-tillage systems is the presence of pre-planting weeds that can compete with plants in the absorption of growth factors such as nutrients, light, and water. This experiment aims to test herbicide doses that effectively suppress weed growth and optimize the growth and yield of upland rice with the no-tillage system. The experiment was conducted from December 2023 to April 2024 at Ciparanje Farm, Faculty of Agriculture, Padjadjaran University, Jatinangor District, Sumedang Regency, West Java Province, Indonesia. The experiment used Randomized Block Design (RBD), consisting of 7 treatments, each repeated four times. The treatments consisted of 5 doses of glyphosate IPA 240 g/L herbicide 2.00, 3.00; 4.00, 5.00; 6.00 L/ha with no-tillage system; manual weeding; and control with perfect tillage system. Experimental results showed that glyphosate IPA 240 g/L herbicide at a dose of 3.00 - 6.00 L/ha with the no-tillage system can be used to replace the perfect tillage system because it can suppress the growth of broadleaf weeds, namely Ageratum conyzoides, Cleome rutidosperma, Mollugo pentaphylla and Synedrela nodiflora, and grass Digitaria ciliaris. No phytotoxicity symptoms were found, and had a favorable effect on rice plant growth regarding population size and tillers. The yield of rice plants with the highest milled dry grain yield was 4.45 t/ha.

Mitigation of soil salinity by addition of different rice straw biochar doses in salt-affected acid soil

The current study was carried out to evaluate the effect of rice straw biochar amendment and to identify the appropriate dose of biochar application to reduce soil acidity, salinity, toxicity, and sodicity in salt-affected acid soils. The rice straw biochar at 4 different rates of 0%, (control) 1%, 3%, and 5% (w/w) was mixed with 6 salt-affected acid soils: S1 (non-saline), S2 and S3 (low saline), and S4, S5, and S6 (moderate saline). The mixture was continuously shaken in distilled water for 7 days. The biochar application significantly increased soil pH and saturated electrical conductivity (ECe) with an increasing biochar application rate compared with the control. Significant decreases in sodium adsorption ratio (SAR) and exchangeable sodium percentage (ESP) values below the critical level of sodicity were observed above the biochar application rate of 1%. Soluble chloride (Cl–) and soluble and exchangeable sodium (Na+) were significantly reduced above the biochar application rate of 1%. The biochar application (≥ 1%) led to a significant increase in soluble and exchangeable potassium (K+) and declines in soluble and exchangeable calcium (Ca2+) and magnesium (Mg2+). This study concluded that the biochar application rate of 1% was suitable for reducing soil acidity to a safe level for rice plants. The rice straw biochar application improved soil toxicity and sodicity by reducing soluble Cl– and soluble and exchangeable Na+, decreasing SAR and ESP. The biochar application also increased available K+, essential for rice plant growth and development in salt-affected soils.

SOS! Hydrogen Sulfide Enhances the Flavonoid Early Warning System in Rice Plants to Cope with Thiocyanate Pollution.

The presence of thiocyanate (SCN-) in irrigation water has adverse effects on both plant growth and crop output. Hydrogen sulfide (H2S) is an important gaseous signaling molecule that can alleviate SCN- stress. Flavonoids are secondary compounds produced by plants and are ubiquitous in the plant kingdom. They play important roles in several physiological and biochemical processes. To investigate the effect of exogenous H2S on the growth of early rice plants under SCN- stress, we carried out a hydroponic experiment focusing on the interaction of exogenous H2S with flavonoids. In this study, a hydroponic experiment was performed to investigate the behavior of SCN- when subjected to varying effective doses (EC20: 24.0 mg/L; EC50: 96.0 mg/L; and EC75: 300.0 mg/L). The findings indicated that the relative growth rate (RGR) of the plants treated with H2S + SCN- was greater than that of the plants treated with SCN- alone. Higher amounts of flavonoids were detected in the shoots than in the roots, with more variability in the shoots. The early warning level results showed that most of the flavonoids were present at levels I and II, while quercetin was present at level IV. Genetic expression variation factor (GEVF) analyses revealed an increase in the quantity of "promoter genes" with increasing SCN- concentration in both rice tissues. Furthermore, administering external H2S while exposing rice tissues to SCN- resulted in a considerable decrease in the levels of reactive oxygen species. This study provides novel insights into the regulation of flavonoid levels in rice plants by exogenous H2S, facilitating enhanced resistance to SCN- stress and promoting sustainable agriculture.

Synergistic effects of combined application of biochar and arbuscular mycorrhizal fungi on the safe production of rice in cadmium contaminated soil

Arbuscular mycorrhizal fungi (AMF) have been shown to effectively mitigate the detrimental effects of heavy metal stress on their plant hosts. Nevertheless, the biological activities of AMF were concurrently compromised. Biochar (BC), as an abiotic factor, had the potential compensate for this limitation. To elucidate the synergistic effects of biotic and abiotic factors, a pot experiment was conducted to assess the impact of biochar and AMF on the growth, physiological traits, and genetic expression in rice plants subjected to Cd stress. The results demonstrated that biochar significantly increased the mycorrhizal colonization rate by 22.19 %, while the combined application of biochar and AMF led to a remarkable enhancement of rice root biomass by 42.2 %. This resulted in a shift in spatial growth patterns that preferentially promoted enhanced underground development. Biochar effectively mitigated the stomatal limitations imposed by Cd on photosynthetic processes. The decrease in IBRv2 (Integrated Biomarker Response version 2) values suggested that the antioxidant system was experiencing a state of remission. An increase of Cd content within the rice root systems was observed, ranging from 33.71 % to 48.71 %, accompanied by a reduction in Cd bioavailability and mobility curtailed its translocation to the aboveground tissues. Under conditions of low soil Cd concentration (Cd ≤ 1 mg·kg−1), the Cd content in rice seeds from the group subjected to the combined treatment remained below the national standard (Cd ≤ 0.2 mg·kg−1). Furthermore, the combined treatment modulated the uptake of Fe and Zn by rice, while simultaneously suppressing the expression of genes associated with Cd transport. Collectively, the integration of biological and abiotic factors provided a novel perspective and methodological framework for safe in-situ utilization of soils with low Cd contamination.

Study of Nitrogen and Phosporus Doses on The Growth and Yield of Rice Plant (Oryza sativa L.) Mekongga Variety Used

The rice plant (Oryza sativa L.) is the main food commodity in Indonesia, but its production has not shown a significant increase. To increase rice productivity, especially in rainfed areas, it is necessary to optimize the use of nutrients such as nitrogen and phosphorus. Facing the challenges of low fertility and limited water availability, endophytic bacterial consortia can help increase nutrient availability and plant growth. The aim of this research was to determine the effect of nitrogen and phosphorus doses and their interactions on the growth and yield of the Mekongga rice variety in rainfed land where a consortium of endophytic bacteria was applied. The treatments carried out were designed as a factorial experiment in a Randomized Completely Block Design, namely the Nitrogen factor consisting of four dose levels: 0, 92, 184, 276 kg/ha and the Phosphorus factor consisting of four dose levels: 0, 72, 144, 216 kg/ha with three repetitions. The results showed that differences in nitrogen doses had a significant effect on the number of grains per panicle of rice plants, but did not have a significant effect on other growth and yield parameters of rice plants. Varying phosphorus doses and combinations of nitrogen and phosphorus doses did not have a significant effect on all growth and yield parameters of the Mekongga rice variety.

Effects of Phosphorus and Potassium Supply on Photosynthetic Nitrogen Metabolism, Nitrogen Absorption, and Nitrogen Utilization of Hydroponic Rice

Phosphorus (P) and potassium (K) stress significantly affect the growth, physiological characteristics, and nutrient uptake of rice plants. This study investigated the photosynthetic nitrogen (N) metabolism, N uptake, and N utilization of plants under varied P and K supplies. Two local conventional high-yield rice varieties (Shennong 265 and Liaojing 294) were used. These varieties were subjected to the following hydroponic experimental treatments: HPHK (normal P and K concentrations), HPLK (normal P and 1/20 normal K concentration), LPHK (normal K and 1/20 normal P concentration), and LPLK (1/20 normal P and K concentrations). The results showed that the mesophyll cells had a relatively complete nuclear and chloroplast structures, and the antioxidant enzymes of the plants were significantly reduced under the HPHK treatment. Compared to the LP treatments (LPHK and LPLK), the HPHK treatment was found to have the following potential effects: effectively optimize plant configuration; promote leaf development (Pn, E, Ci, and Tr, chlorophyll, and leaf area index); significantly increase the N-metabolism-related enzyme activity of leaves and roots and the accumulation of N in the plant in the main growth stages; and significantly increase the rice yield and N-related efficiency. In conclusion, the HPHK treatment was found to be beneficial in improving the plant configuration, promoting photosynthetic N metabolism, and increasing grain yield and N-related utilization efficiency.

Isolation, screening, and molecular characterization of indigenous Trichoderma isolates from West Java, Indonesia and their plant growth-promoting capability on rice plants (Oryza sativa L.)

Trichoderma species are widely acknowledged as growth-promoting fungi that have been utilized to enhance the growth and yield of numerous crops. This research examined the capacity of 30 Trichoderma strains, isolated from two organic rice fields in West Java, Indonesia, to enhance the germination, growth, and physiological characteristics of rice plants (Oryza sativa L.). In general, Trichoderma strain TM10 demonstrated the greatest ability to increase seed germination (97.25 %), vigor index (3122.83), and germination speed (59.91 seeds/day). This strain also increased seedling root length and seedling height by 101.62 % and 112.20 %, respectively. Plants treated with TM10 exhibited a notable improvement in root length, plant height, fresh weight, and dry weight compared to control plants, demonstrating increases of 188.68 %, 69.90 %, 157.41 %, and 159.38 %, respectively. Furthermore, the total chlorophyll content and stomatal number in TM10-treated plants exhibited increments of 75.23 % and 75.53 %, respectively. Five selected isolates (TM7, TM10, SB2, SB8, and SB14) were evaluated for their potential to produce plant growth-promoting compounds, including phosphatase enzyme (ranging from 0.54 to 11.14 µg pNP g−1h−1), indole-3-acetic acid (IAA) (ranging from 28.96 to 63.91 µg/mL), ammonia (ranging from 1.96 to 5.79 µg/mL), and hydrogen cyanide (HCN) (ranging from 221.76 to 274.82 ppm). The best strain, namely TM10, was then molecularly identified as Trichoderma yunnanense. This investigation demonstrates that Trichoderma spp. isolated from organic rice fields could be used as a bioinoculant in sustainable rice production.

Effectiveness of local isolates of Trichoderma spp. in imparting drought tolerance in rice, Oryza sativa

Rice is a crop that requires high amount of water, and the drought is a major constraint in paddy cultivation. Water stress condition frequently prevails due to shortage of rain which results in significantly reduced plant growth and yield of rice. In the present study capability of Trichoderma spp. in imparting drought tolerance to rice, Oryza sativa was explored. Eleven local strains of Trichoderma spp. were applied to rice cv. Swarna Sub-1 through soil application (2 g/kg soil) and seed treatment (20 g/kg seed) under 0, 25, 50 and 75% less watering of the recommended amount. The soil application of T. harzianum AMUTHZ84 significantly promoted the shoot and root length (23.6 and 21.3%) followed by seed treatment (19.7 and 18.2%) under recommended level of irrigation condition (100% irrigation). Next in effectiveness was T. viride AMUTVR73 (21.5 and 18.1%) over untreated control. However, under 75% water availability, soil application with T. harzianum AMUTHZ82 was found superior over other isolates in enhancing shoot and root length (17.7 and 16.4%). The same isolate was also recorded to be superior under 50% (12.4 and 10.1%) and 25% water availability (9.3 and 8.1%) in enhancing the plant growth and biomass of rice cv. Swarna Sub-1. The isolate also significantly enhanced the leaf pigments, and photosynthesis in the rice plants grown under 25–75% water stress condition. In general, soil application of Trichoderma isolates was found more effective than seed treatment, and the T. harzianum AMUTHZ82 provided 8–17% enhancement in the plant growth, biomass, leaf pigments and photosynthesis of rice cv. Swarna Sub-1 grown under 25–75% water stress condition.

Effect of microbial consortium application on growth and yield of Oryza sativa L.

A group of microorganisms (bacteria, viruses, fungi, and other microbes) working together to perform a specific task is called a consortium. This study aims to study and determine the growth and yield response of rice plants to the application of a consortium of phyllosphere microbes Fm48 and rhizosphere microbes R15. This research has been conducted since from August to November 2021 in the rice fields of Boya Baliase Village, Marawola District, Sigi Regency, Central Sulawesi Province. This study used a one-factor randomized block design method with grouping based on plot height. The treatment that was tried consisted of four levels, that is: Control = Without applied microbes, Fm48 = Applied a consortium of phyllosphere microbes Fm48, R15 = Applied a consortium of rhizosphere microbes R15 and Fm48R15= Applied a consortium of phyllosphere microbes Fm48 and rhizosphere microbes R15. To determine the effect of the treatment being tested, a variance analysis was carried out. Analysis of variance which showed a significant effect, further test was carried out for LSD α = 0.5. The results showed that the treatment of various consortiums of phyllosphere microbes Fm48 and R15 rhizosphere microbes had no significant effect on growth parameters but had a significant effect on the number of hollow grains and grain weight per 1000 rice grains. The consortium of phyllosphere microbes Fm48 and rhizosphere microbes R15 gave the best results for the lowest number of hollow grains and the highest grain weight per 1000 rice grains.