Characteristics Of Rice Plant Research Articles

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.

Pengaruh pemberian air kotoran ikan dan biourin domba terhadap karakteristik fisiologi tanaman padi (Oryza sativa L.) Varietas inpari 32

One of the factors that influences plants physiological processes is the absorption of nutrients obtained from both organic and inorganic fertilizers. Some organic fertilizers that can be given are fish waste water and sheep urine fertilizer. The aim of this research is to obtain information regarding the effect of fish waste water and sheep biourine on the physiological characteristics of rice plants (Oryza sativa L.) such as leaf chlorophyll content, Net Assimilation Rate (NAR) and Crop Growth Rate (CGR). This research was conducted on Agricultural Extension Field, Majalaya District, Karawang Regency, from January to April 2022. This experiment used an experimental method with a split plot design (Split Plot Design) with 10 treatment combinations which were repeated 3 times. The main plots are fish waste water (A): A1 (fish waste water), and A2 (ordinary irrigation water). As subplots for Sheep Biourine (P): P0 (Control), P1 (Factory Biourine 100 ml/l), P2 (Sheep Biourine 100 ml/l), P3 (Sheep Biourine 150 ml/l) and P4 (Sheep Biourine 200 ml /l). The research results showed that there was no interaction between biourine fertilizer treatment and fish waste water on the physiology characteristics of the rice plants (Oryza sativa L.).

Straw application improved soil biological properties and the growth of rice plant under low water irrigation

The application of organic amendments is one way to manage low water irrigation in paddy soils. In this 60-day greenhouse pot experiment involving paddy soil undergoing drying-rewetting cycles, we examined the effects of two organic amendments: azo-compost with a low carbon to phosphorus ratio (C:P) of 40 and rice straw with a high C:P ratio of 202. Both were applied at rates of 1.5% of soil weight (w/w). The investigation focused on changes in certain soil biochemical characteristics related to C and P in the rice rhizosphere, as well as rice plant characteristics. The irrigation regimes applied in this study included constant soil moisture in a waterlogged state (130% water holding capacity (WHC)), mild drying–rewetting (from 130 to 100% WHC), and severe drying–rewetting (from 130 to 70% WHC). The results indicated that the application of amendments was effective in severe drying–rewetting irrigation regimes on soil characteristics. Drying–rewetting decreased soil respiration rate (by 60%), microbial biomass carbon (by 70%), C:P ratio (by 12%), soil organic P (by 16%), shoot P concentration (by 7%), and rice shoot biomass (by 30%). However, organic amendments increased soil respiration rate (by 8 times), soil microbial biomass C (51%), total C (TC) (53%), dissolved organic carbon (3 times), soil available P (AP) (100%), soil organic P (63%), microbial biomass P (4.5 times), and shoot P concentration (21%). The highest significant correlation was observed between dissolved organic carbon and total C (r= 0.89**). Organic amendments also increased P uptake by the rice plant in the order: azo-compost > rice straw > control treatments, respectively, and eliminated the undesirable effect of mild drying–rewetting irrigation regime on rice plant biomass. Overall, using suitable organic amendments proves promising for enhancing soil properties and rice growth under drying–rewetting conditions, highlighting the interdependence of P and C biochemical changes in the rhizosphere during the rice vegetative stage.

Selecting iron and zinc nano-fertilizers for rice traits in drought by statistical analysis.

Optimum use of fertilizer plays an important role in increasing the performance of traits in rice and other agricultural products. The use of nano-fertilizers can be very important in the optimal use of fertilizer and in increasing the quantity and quality of agricultural products. To investigate the effect of iron and zinc nano-fertilizers on the physiological and morphological characteristics of rice plants (Tarom Hashemi variety) under drought stress conditions, a split plot experiment was carried out in the form of a randomized complete block design in three replications in Mazandaran region. The results of the combined analysis indicated that the effect of iron nano-fertilizer and zinc nano-fertilizer has a significant difference at the level of 0.01 and 0.05 in terms of all the evaluated traits. In the means comparison, it was concluded that normal humidity conditions can have a positive effect on the performance of the traits, but in the S1 stress conditions (drought stress at the rate of 50% of normal irrigation), the traits showed a good performance trend. Furthermore, increasing the amount of iron nano-fertilizer at the F2 level (Iron sulphate 100 kg/ha + 1 foliar spraying of iron chelate 2%) can be very effective in the growth of yield and the desirability of traits. In examining the amount of zinc nano-fertilizer consumption on the traits, showed the most positive performance on the traits at the level of Z2 (Use of 5 mg of zinc nano-fertilizer per kg of experiment soil), but with the increase to the level of Z3 (Use 7.5 mg of zinc nano-fertilizer per kg of experiment soil), this favorability was greatly reduced. The result of the correlation coefficients between the traits and the correlation diagram also showed a positive and significant correlation between the traits. In the graphical analysis, treatments tr33, tr8, tr19, tr24, tr7, tr6, and tr2 were selected as desirable treatments from the polygon graph. Treatments tr19, tr9 and tr6 were recognized as favourable treatments in terms of the treatment ranking diagram in terms of all traits. Based on the treatment selection diagram based on ideal treatment, tr19, tr9 and tr6 treatments were identified as desirable treatments. In general, it is possible to use tr19 (S1×F1×Z2), tr6 (N×F1×Z1) and tr9 (N×F2×Z0) treatments as treatments with high efficiency and power to increase the performance of traits and optimal use of nano-fertilizers in rice cultivation.

Some Agronomical and Physiological Characteristics of Sang Yod Phatthalung Rice from In Vitro Regenerated Plant After Transfer to Clay Soil in Field Conditions

Sang Yod Phatthalung rice is indica rice and grown as Geographical Indications (GI) in Patthalung province. Its dark red color seed contains high antioxidant activity that helps reduction in the risk of some chronic diseases such as diabetes, cancer, and cardiovascular diseases. So far, yield per planting area of this rice is still low. Thus, application of PGRs might play an alternative role in agronomical and physiological characteristics leading to improving yield of this rice. First, shoot tips of Sang Yod Phatthalung rice were cultured to induce multiple shoots and root on liquified PGR-free oil palm culture medium (OPCM) with different concentrations of 6-benzyladenine (BA) (0, 0.5, 1, 1.5 mg/L) alone or in combination with 1-naphthaleneacetic acid (NAA) (0 and 0.5 mg/L). Complete plants were acclimatized to field condition at Phatthalung Rice Research Station (PRRS). After acclimatization for 120 and 140 days, some agronomical and physiological characteristics of rice plant obtained from different PGR containing OPCM were statistically compared. A 2×4 factorial design in RCBD with 4 replication was performed. The results were clearly demonstrated that adding BA in the culture medium increase plant height, number of panicles, panicle length and leaf chlorophyll content. Plantlets obtained from in vitro culturing shoot tip on 0.5 mg/L BA containing medium gave the highest results in average plant height at 189.50 cm, number of panicles at 34.00 panicles, panicle length at 32.50 cm and leaf chlorophyll content at 39.65 SPAD unit. The results from this present study indicated the production of new plant types or characteristics for Sang Yod Phatthalung rice for high yield in future. HIGHLIGHTS The effect of concentrations of PGRs, and culture conditions on agronomical and physiological characteristic were evaluated 5 mg/L BA-derived plants germinated in vitro gave higher results than ex vitro in agronomical and physiological characteristic Addition of 0.5 mg/L BA in the medium increases the plant height, number of panicles, panicle length and leaf chlorophyll content 5 mg/L BA-derived plants in vitro gave the highest plant height, number of panicles, panicle length, and leaf chlorophyll content at 189.50 cm, 34.00 panicles, 32.50 cm, and 39.65 SPAD units, respectively GRAPHICAL ABSTRACT

Exogenous silicon enhances resistance to 1,2,4-trichlorobenzene in rice

Environmental contamination with 1,2,4-trichlorobenzene (TCB) is a threat to rice growth, and ultimately, to human health. Silicon (Si) plays an important role in plants' stress responses. However, little is known about the effects of Si on the TCB tolerance of rice plants. We investigated the effects of Si on the morphological, physiological, and molecular characteristics of rice plants under TCB stress. First, we compared the TCB tolerance of 13 rice cultivars by measuring seven growth-related and 13 physiological indices across four treatments. Then, six cultivars with contrasting TCB tolerance were selected to study the expression of Si transport and detoxification related genes. Compared with the control, the TCB treatment resulted in decreased growth indices, chlorophyll content, and antioxidant enzyme activities, and increased the superoxide anion content and root electrical conductivity. Application of Si improved rice growth, chlorophyll content and alleviated oxidative damage caused by TCB. The alleviating effect of Si ranged from 4.1 % to 56.72 % among the cultivars, with the strongest alleviating effect on Wuyujing 36. The transcript levels of genes encoding Si transporters and detoxification enzymes were higher in tolerant cultivars than in sensitive cultivars. The TCB treatment induced the expression of GST and Lsi2 in roots and HO-1 in leaves; these genes as well as Lsi1 were differentially expressed in roots and/or leaves in the TCB + Si treatment. Lsi1 played a key role in Si-mediated TCB tolerance in Wuyujing 36. The joint analysis of gene transcript levels in TCB and TCB + Si treatments confirmed that all six genes were associated with TCB tolerance, especially Lsi1 and Lsi2 in roots and GST and CuZn-SOD in leaves. Si can increase rice plants' resistance to TCB stress by improving growth and enhancing superoxide dismutase (SOD) activity and chlorophyll content, and by up-regulating genes involved in Si transport and detoxification.

MAPPING SPATIAL DISTRIBUTION OF MAIN SEASON RICE FIELDS IN EASTERN NEPAL USING MULTI-TEMPORAL LANDSAT 8 IMAGES

Mapping rice area can be beneficial for change detection, irrigation management, climate change impact and vegetation protection and restoration programs. Remote sensing has provided a vantage means of mapping rice area. The unique physical characteristics of rice plants is that it is grown in flooded soil, which significantly affect the spectral reflectance from the rice fields. After a period of two months, the dense rice canopy cover replaces the flooded soil. This dynamic of the rice field is captured with the help of vegetation indices and are used to identify rice fields. Multi-spectral and multi-temporal data Landsat 8 data is used in the study. An algorithm that uses Normalized difference vegetation index (NDVI) and Land-surface Water Index (LSWI) derived from Landsat 16-days 30-meter data was used to differentiate paddy field from other areas. It works on the basis of sensitivity of LSWI for surface moisture and NDVI for vegetation content. This algorithm was used to detect rice fields in twelve local levels in Sunsari and Morang districts of Nepal. The results were validated using 0.44m resolution digital globe satellite imagery with 79 well-distributed control points. The overall accuracy of the method was found to be 79.746%.

Effects of cultivation techniques on CH4 emissions, net ecosystem production, and rice yield in a paddy ecosystem

This study analyzed the effects of traditional rice cultivation (TC), ridge tillage and terrace rice cultivation (RC), and ridge tillage and terrace rice cultivation plus loach (Misgurnus anguillicaudatus) breeding in ditches (RLC) on methane (CH4) emissions and daytime net ecosystem production (NEP) of CO2 fluxes in a paddy ecosystem using the ultra-portable greenhouse gas (GHG) analyzer with a static transparent chamber. Rice plant characteristics and yields were also measured with field experiments and laboratory analysis. The aim was to explore the possible contribution of the rice ridge terraced cultivation to yield while reducing GHG emissions. We found that (1) RC has the highest rice yield for both the early-and late-season rice, followed by TC and RLC. (2) The combined CH4 emission and daytime NEP values were the least for RC during the double growing season, followed by TC and RLC. (3) Comparing the cumulative global warming potential and yield-scaled emission, RC showed the lowest GHG emission and the highest NEP for the double growing season, followed by TC and RLC. The results indicated that RC was beneficial for increasing rice yields while decreasing CO2 and CH4 emissions in the paddy ecosystem.

Potential option for mitigating methane emission from tropical paddy rice through selection of suitable rice varieties

Cultivation of rice, a globally important cereal crop, is a major cause of emission of the greenhouse gas (GHG) methane (CH4), giving rise to global warming. Physiological and anatomical characteristics of rice plants associated with CH4 emission were studied in six high-yielding rice varieties, Dikhow, Dishang, Jaya, Kolong, Kopilee and Lachit, during the pre-monsoon season (April–August) for 2 years (2013 and 2014) in a tropical climate in India. Significant differences (P < 0.001) in photosynthetic rate among the rice varieties were recorded and were found to influence CH4 emission from the ecosystem. Rate of CH4 emission was found correlated (r = 0.942) with size of the xylem vessels of the node of the varieties. Kolong, Lachit and Dikhow were identified as low CH4 emitters with smaller xylem vessels. The recorded GHG intensity (GHGI) revealed rice varieties as a source of GHGs, and among the varieties, Kopilee as a major source of CH4, with GHGI of 0.083 and 0.093 during 2013 and 2014, respectively. Results suggest that selection of suitable rice varieties with high grain yield accompanied by lower rate of CH4 emission can be a viable option for reduction of CH4 emissions from rice agriculture.

Aboveground morphological traits do not predict rice variety effects on CH4 emissions

High-yield varieties with low methane emissions will benefit sustainable rice (Oryza sativa L.) production. However, no specific plant characteristics have been identified to be primarily responsible for rice variety impacts on the CH4 emission. We conducted a comprehensive study through comparing effects of 66 varieties on CH4 under both greenhouse and field conditions to identify rice plant characteristics that may significantly affect soil CH4 emission. Although there were significant differences in CH4 emissions among the tested rice varieties, no significant and consistent relationships were observed between aboveground traits and CH4 fluxes or dissolved CH4 concentrations in soil solutions. Yet dissolved CH4 concentrations were significantly correlated with the mean CH4 flux over the growing season. In addition, cutting rice plants 5cm off above the floodwater did not increase CH4 fluxes, indicating that the CH4 transport through the removed part of rice plant contributed little to the total CH4 emission. Taken together, our results indicate that differences in CH4 emissions among rice varieties primarily stem from the differential effects of rice plants on the belowground CH4 production and oxidation. Aboveground plant traits do not provide reliable predictions of variety effects on CH4 emissions. Future efforts should be focused on understanding belowground processes and the underlying mechanisms that govern rice variety impacts on the CH4 emission.

Can we create “Elite Rice”—a multifunctional crop for food, feed, and bioenergy production?

Because arable land is limited, land use for food and bioenergy production remains a controversial issue. If food crops can generate high yields and the biomass can also be used effectively for both animal feed and bioenergy production feedstock, conflicts over land use can be reduced. Rice is an important crop; as a worldwide staple food with abundant residuals (polysaccharide-rich straw) after grain collection, this crop plant is attractive as a renewable raw material for bioenergy and feed production. Here, we address current issues and discuss promising methods for improving rice plant characteristics suitable for food, feed, and bioenergy production. Advanced genetic engineering techniques can be used to precisely manipulate the mechanisms regulating grain production, cellulose and lignin content, and stress tolerance. In addition, genetic modification of the mechanisms controlling glycoside hydrolase expression can enhance biomass saccharification for bioenergy production and improved animal digestibility. We also address the issue of nutrient recycling associated with rice straw utilisation for biofuel production.

The Effect of Macro and Micro-nutrient Fertilizers on Yield and Yield Attributes of Rice in a Calcareous Soil

In order to examine the effect of macro and micronutrient fertilizers on the growth and yield of rice (Oryza sativa L.) under calcareous soils, the experiment carried out as splitsplit plot design in randomized complete block with three replications. Macro, sulfur powder and micronutrient fertilizers have chosen as main, sub and sub-sub plots, respectively. The amount of lime and pH of the experimental soil is 16.7% and 7.54, respectively that categorized as calcareous soils. The aim of the present study is decrease soil pH at the five stages of rice plant growth and investigation of vegetative growth and rice grain yield. The results showed that soil pH decreased by using NPK+S+Zn fertilizers (0.32) compared to the control plot. With decreasing soil pH all the agronomic characteristics of rice plant and its grain yield increased significantly, except 1000-grain weight. The number of filled grain (119) and total number of seed per panicle (127) and grain yield (4376 kg ha) reached at the maximum values when NPK+S+Zn fertilizers applied together. Rice grain yield was increased 1483 kg ha by this treatment compared to the control plot (2893 kg ha). Thus, this treatment can be resulted as the best treatment under calcareous soils conditions with high soil pH.

Of yield gaps and yield ceilings: Making plants grow in particular places

The System of Rice Intensification (SRI) and rice genetic improvement are proposed as two approaches to improving and increasing rice production. In recent exchanges, they have been represented by their respective supporters as starkly contrasting, almost mutually incompatible alternatives. However, advocates on both sides of this argument have tended to stress the genetic and physiological characteristics of rice plants and place less emphasis on the spatially and temporally situated knowledge and management skills of farmers, which are the means by which any agricultural technology is locally adapted and integrated into livelihood strategies, and technological potential is translated into real outcomes in specific settings. Taking this proposition seriously would entail a substantial reorganisation of agricultural research and extension, bridging the historical divide between these two wings of professional agronomy. It would require agronomists of both types to work more collaboratively with farmers. It would also require scientists to produce new kinds of outputs, such as analytical frameworks, heuristics and decision-making tools to help farmers apply scientific insights to their own constrained circumstances. This argument is made with reference to the cases of SRI (a cultivation system that is said to boost farm yields without the need for genetically improved germplasm) and C4 rice (a crop-improvement project intending to ‘supercharge’ rice photosynthesis to increase rice yields). The paper uses the agronomic concepts of the ‘yield gap’ and the ‘yield ceiling’ to offer a perspective on strategic questions about the goals and organisation of agricultural research and extension.

Effects of different soil amendments on the remediation of Cd-contaminated soil and the photosynthetic characteristics of rice plant

Effects of different soil amendments on the remediation of Cd-contaminated soil and the photosynthetic characteristics of rice plant

Relativity between CH<SUB>4</SUB> and N<SUB>2</SUB>O emission and rice plant characteristics

Relativity between CH<SUB>4</SUB> and N<SUB>2</SUB>O emission and rice plant characteristics

Comparative Performance of Rice with System of Rice Intensification (SRI) and Conventional Management using Different Plant Spacings

AbstractThe System of Rice Intensification (SRI) reportedly enhances the yields of rice (Oryza sativa L.) through synergy among several agronomic management practices. This study was conducted to investigate the effects on rice plant characteristics and yield by comparing the plants grown with different methods of cultivation – SRI vs. recommended management practices (RMP) focusing on the impact of different plant spacings.Performance of individual hills was significantly improved with wider spacing compared with closer‐spaced hills in terms of root growth and xylem exudation rates, leaf number and leaf sizes, canopy angle, tiller and panicle number, panicle length and grain number per panicle, grain filling and 1000‐grain weight and straw weight, irrespective of whether SRI or RMP was employed. Both sets of practices gave their highest grain yield with the spacing of 20 × 20 cm; however, SRI yielded 40 % more than the recommended practice. At this spacing, canopies also had the highest leaf area index (LAI) and light interception during flowering stage. The lowest yield was recorded at 30 × 30 cm spacing under both the practices, as a result of less plant population (11 m−2), despite improved hill performance.During the ripening stage, hills with wider spacing had larger root dry weight, produced greater xylem exudates, and transported these towards shoot at faster rates. These features contributed to the maintenance of higher chlorophyll levels, enhanced fluorescence and photosynthesis rates of leaves and supported more favourable yield attributes and grain yield in individual hills than in closely‐spaced plants.Moreover, these parameters further improved in SRI, apart from the enhanced percentage of effective tillers and showed substantial and positive impacts on grain yield (17 %) compared with recommended practice. In conclusion, wide spacing beyond optimum plant density, however, does not give higher grain yield on an area basis and for achieving this, a combination of improved hills with optimum plant population must be worked out for SRI.

Assessment of N topdressing rate at panicle initiation stage with chlorophyll meter-based diagnosis in rice

This study was conducted to determine N topdressing rate at panicle initiation stage by using chlorophyll meter (SPAD-502)-based N nutritional diagnosis in rice plant for high quality production of the Chucheongbyeo variety. Field experiments were carried for 3 years from 2003 to 2005 in Gyeonggi, Hwaseong. To confirm the method of measuring the leaf color with SPAD-502, leaf position of rice plant and measuring point on the leaf were studied. And the proper period to examine the leaf color and growth characteristics of rice plants was suggested at panicle initiation stage, from the results of the correlation between SPAD value and both content of chlorophyll and nitrogen in rice leaves. The multiply value of plant height, number of tillers per m2 and SPAD value could explain well the effect of nitrogen fertilization on the growth of rice plants, and was used to determine an equation for on-site determination of nitrogen fertilization rate for Chucheongbyeo variety at the panicle initiation stage. Nitrogen fertilization increased number of tillers and rice yields, and affected the increase in protein content in rice grain resulting in loss of quality, such as taste value, and decreased the percentages of both ripened and whole rice grains. Based on the response surface statistical methodology using the SAS program, the relationship equation among protein content of brown rice (PROT), plant growth value (plant height × number of tillers × SPAD value, PGV), and nitrogen fertilization rate at the panicle formation stage (NF) was developed. That is, PROT (%) = 7.379403 − (5.27E-7) a − 0.013291 b + (3.025355E-13) a2 + (3.222997E-8) ab + (6.781E-05) b2, where a means PGV and b is NF (%), and the equation’s coefficient of determination (R2) was 0.967. From this equation, to recommend the optimum N fertilization rate at panicle initiation stage easily to produce high quality rice of Chucheongbyeo variety, which contains the target protein content of brown rice.

Characteristics of Rice Plant for Forage-use and It's Introduction to Abandoned Farmlands

Characteristics of Rice Plant for Forage-use and It's Introduction to Abandoned Farmlands

Methane emission associated with anatomical and morphophysiological characteristics of rice (Oryza sativa) plant

Plant-mediated transport is the primary route of methane (CH(4)) emission from the reduced paddy field to the aboveground atmosphere. Experiments were conducted at North Bank Plain Agro-climatic Zone of Assam, India, during monsoon rice-growing season (July to December 2006) to elucidate the influences of anatomical and morphophysiological characteristics of rice (Oryza sativa L.) cultivars on methane emission from submerged agroecosystem. Ten rice cultivars were grown in light-textured loamy soil under rainfed uniform field condition. Among the 10 cultivars, 5 were traditional rice genotypes commonly grown in the agroclimatic zone and the other 5 were improved high-yielding varieties. Wide variation in CH(4) flux was recorded among the rice cultivars, which may be regulated by the difference in anatomical and morphophysiological characteristics of rice plant. Microscopic analysis of stem portion showed that high- and medium-CH(4)-emitting cultivars recorded higher size of the medullary cavity. Leaf area and transpirational rates were also found to be higher in high-CH(4)-emitting varieties. Scanning electron microscopic analysis revealed higher stomatal frequencies in high-methane-emitting cultivars. Data presented in this study suggest that variation in anatomical and morphophysiological characteristics among different rice genotypes may influence CH(4) emission from paddy fields.

Effect of phosphorus deficiency on the photosynthetic characteristics of rice plants

The effects of phosphorus deficiency on the photosynthetic characteristics were studied in rice seedlings (Oryza sativa L.) every 8 days after treatment. P deficiency caused a significant reduction in the net photosynthesis rate (PN) in rice plants. During the first 16 days of P deficiency, the maximum efficiency of PSII photochemistry (Fv/Fm), the effective PSII quantum yield (ϕPSII), the electron transport rate (ETR) as well as photochemical quenching (qP) in the P-limited rice plants kept close to the control, but the excitation energy capture efficiency of PSII reaction centers (F′v/F′m) was significantly declined in the P-deficient rice leaves. Meanwhile, in the stressed leaves, we also found a significant increase in nonphotochemical quenching (NPQ) as well as in the activities of superoxide dismutase (SOD) and ascorbate peroxidase (APX). It was indicated that a series of photoprotective mechanisms had been initiated in rice plants in response to short-term P deficiency. Therefore, PSII functioning was not affected significantly under such stress. As P deficiency continued, the excess excitation energy was accumulated in excess of the capacity of photoprotection systems. When the rice suffered from P deficiency more than 16 days, ϕPSII, ETR, and qP were decreased more rapidly than that in the control plants, although NPQ still kept higher in the stressed plants. These results were also consistent with the data on the distribution of excitation energy. The excess energy induced the generation of reactive oxygen species, which might lead to the further damage to PSII functioning.