Uptake and metabolism of isouron in rice (Oryza sativa L.) seedlings

Summary Isouron, a pre-emergence herbicide, inhibited the growth of rice seedlings in a nutrient solution; the critical concentration was about 0.10 mg l^-1. Isotope studies showed that isouron, added to the nutrient solution, was observed by the rice roots and translocated rapidly to the shoot. In rice seedlings, isouron was converted to six known metabolites, 3-(5-(1-dimethyl-2-hydroxy-ethy)-3-isoxazolyl]urea, 3-(5-tert-butyl-3-isoxazolyl)-1-methylurea, 3-(5-tert-butyl-3-isoxazolyl)ure, 3-amino-5-tert-butylisoxazole, 3-[5-(1,1-dimethyl-2-hydroxyethyl)-3-isoxazolyl]-1-dimethylurea, and 3-[5-(1,1-dimethyl-2-hydroxyethyl)-3-isoxazolyl]-1-methylurea, and two unknown metabolites.     

Comparison of protein quality and mineral element concentrations in grain of spelt (Triticum spelta L.) and common wheat (Triticum aestivum L.)

The cultivation of Triticum spelta (spelt) has no tradition in Hungary. In recent years the interest towards this old species renewed in many countries. This high‐nutritional cereal, which has a high ash and fibre content, can be used in many health‐oriented grain‐based food products. Therefore, field experiments have been conducted for some years to test the performance of this species under home growing conditions. Here we report the results of analyses for some important quality parameters of grain samples from the 1996/97 season in comparison with those of older and new home‐grown bread wheat cultivars. Three common wheat cultivars and one advanced spelt line were grown on small plots fertilised with an NPK dose necessary to reach the highest yield and quality. Spikes were sampled weekly from the time of 70–77% grain moisture to full ripening. The grains were analysed for ash, N, P and K content and amino acid composition. Concentrations of 16 other macro + micro elements and in the ripe grains, baking quality parameters were also assessed. The grain development of spelt showed a remarkable time‐lag compared to that of the common wheat cultivars. However, the highest thousand‐grain‐masses, ash, N, and P concentrations were measured in this cultivar after milk ripening. The grains of spelt contained the macro‐nutrient Mg and four micro‐nutrients (Zn, Mn, Fe, Cu) in higher concentrations compared to those of the common wheat varieties. The total and essential amino acid concentrations measured in the ripe grains of spelt were also remarkably higher.

Although its wet gluten content (47.5%) was considerably higher than that of the bread wheat cultivars, its breadmaking quality was poor.     

UV-B辐射增强对水稻多胺含量及其相关酶活性的影响

试验研究表明,处理前期(7～14d)UV-B辐射增强使“汕优63”水稻精氨酸脱羧酶(ADC)、鸟氨酸脱羧酶(ODC)和S-腺苷蛋氨酸脱羧酶(SAMDC)活性分别增加165.74％、104.60％和89.60％,“南川”(NC)运3种酶活性分别增加59.91％、41.30％和23.68％,新品系“IR_(65600-85)”在UV-B辐射胁迫下多胺脱羧酶活性表现与前2品种略不同,即ADC和ODC活性分别提高115.93％、14.45％,而SAMDC活性下降33.01％。处理后期(21～28d)随UV-B辐射累积量的增加,这3种酶活性均有所下降,其中ODC和SAMDC活性降幅大于ADC,其中“汕优63”ADC、和ODC活性分别比对照增加89.72％、3.71％,“南川”则分别增加73.95％、27.38％,“IR_(65600-85)”ADC活性增加94.41％,ODC、活性却下降13.57％。处理后期(21～28d)3类水稻“汕优63”、“南川”和“IR_(65600-85)”SAMDC分别下降40.06％、19.20％和38.21％。多胺氧化酶(PAO)活性变化趋势则相反,即处理前期(7～14d)呈不同程度下降趋势,处理后期(21～28d)则呈极显著上升趋势,其结果引起多胺(PA)含量特别是腐胺(Put)含量明显上升。水稻对UV-B辐射增强的反应具有基因型差异。     

籼稻2个杂种F1种子活力和劣变处理后生化性状的比较

为明确杂交稻种子在储藏过程中品种间抗老化能力的差异,采用人工老化方法研究了杂交籼稻“汕优63”F1;和“特优559”F1种子活力,比较了2品种劣变后9个生化性状的变化。结果表明：种子活力,SOD、POD、CAT、脱氢酶活性,可溶性蛋白含量随种子老化而降低,种子浸出液电导率、可溶性糖和MDA含量随种子老化增加。劣变后“特优559”的SOD、POD、CAT、脱氢酶活性降低程度及可溶性糖和MDA含量增加程度比“汕优63”低,说明“特优559”抗老化能力比“汕优63”强。SOD、POD、CAT、脱氢酶活性和可溶性蛋白含量与种子活力极显著正相关,电导率、可溶性糖、MDA含量与种子活力极显著负相关。     

Variation and correlation analysis of flavonoids and carotenoids in Korean pigmented rice (Oryza sativa L.) cultivars

Flavonoids and carotenoids of pigmented rice ( Oryza sativa L.), including five black cultivars and two red cultivars, from Korea were characterized to determine the diversity among the phytochemicals and to analyze the relationships among their contents. Black cultivars were higher in flavonoids and carotenoids than the red and white cultivars. The profiles of eight phytochemicals identified from the rice grains were subjected to principal component analysis (PCA) to evaluate the differences among cultivars. PCA could fully distinguish between these cultivars. The Heugjinjubyeo (BR-1) and Heugseolbyeo (BR-2) cultivars were separated from the others based on flavonoid and carotenoid concentrations. Flavonoid contents had a positive correlation with carotenoid contents among all rice grains. The BR-1 and BR-2 cultivars appear to be good candidates for future breeding programs because they have simultaneously high flavonoid and carotenoid contents.     

Morphological and molecular evaluation of Turkish rice (Oryza sativa L.) landraces

Genetic Resources and Crop Evolution - This study was carried out to evaluate Turkish rice landraces, in 2016 and 2017. Twenty-nine morphological traits were used for morphological evolution and 10...     

大田条件下模拟UV-B辐射滤减对水稻生长及内源激素含量的影响

对大田栽培条件下人工模拟的UV-B辐射滤减环境对晚稻品种“协优432”的叶绿素含量、株高、内源激素吲哚乙酸(IAA)、脱落酸(ABA)、赤霉素(GA3)、玉米素(Zeatin)含量的影响研究结果表明,在正常日光处理组与UV-A滤光组之间叶绿素a含量变化显著;正常日光处理组与UV-A滤光组、UV-A UV-B滤光组之间株高无明显变化。UV-A UV-B滤光组IAA、GA3、Zeatin含量分别比正常日光处理组降低了40.42%、48.60%、36.21%;分别比UV-A滤光处理组降低了36.52%、70.94%、54.54%。单因素方差分析及多重比较结果显示,UV-A UV-B滤光组与正常日光处理组之间IAA、GA3含量差异显著;UV-A UV-B滤光组与UV-A滤光处理组之间GA3、Zeatin含量差异显著。UV-A UV-B滤光组ABA含量比正常日光处理组降低了29.74%,比UV-A滤光处理组降低了5.19%,经单因素方差分析后发现差异不显著。     

Effect of elevated nitrogen levels on endogenous gibberellin and jasmonic acid contents of three rice (Oryza sativa L.) cultivars

Three rice (Oryza sativa L.) cultivars ( cv. Daesanbyeo, cv. Dongjinbyeo, cv. Junambyeo) were analyzed for endogenous gibberellin (GA) and jasmonic acid (JA) contents and their changes in response to elevated nitrogen (N) levels. The N fertilizer was applied in the form of urea [(NH₂)₂CO] at three rates (0, 36.8, 73.6 kg N ha^–1). Plant growth (height and dry weight) was enhanced by the first N rate but not further enhanced by the highest rate. The endogenous GA contents were analyzed through high‐performance liquid chromatography (HPLC) and gas chromatography–mass spectrometry–selected ion monitoring (GC‐MS‐SIM) while that of JA with GC‐MS‐SIM. They were analyzed one week after N application and were significantly increased with elevated N levels in all rice cultivars. The bioactive GA₁ markedly increased, but its concentration differed in different rice cultivars. Similar fluctuations were observed for endogenous GA₈, GA₁₂, GA₁₉, GA₂₀, and GA₅₃ in response to elevated N levels, showing that the rates of biosynthesis of GAs were differently affected by elevated N levels within different rice cultivars. The level of GA₂₀, a precursor of GA₁ biosynthesis, was not significantly increased, though GA₁₉, a precursor of GA₂₀, was found to be the most abundant GA type in all rice cultivars. Jasmonic acid content in the plants increased with the basic urea application (36.8 kg N ha^–1), but significantly decreased with the double urea level (73.6 kg N ha^–1). The results demonstrate that GA and JA are differentially affected in response to elevated N application in rice.     

Crop growth and nitrogen transformations in wheat (Triticum aestivum L.) planted after wetland rice (Oryza sativa L.)

Summary A field study was undertaken to examine the effects of various management strategies on wheat (Triticum aestivum L.) performance and N cycling in an intensively cropped soil. Microplots receiving 100 kg N ha^–1 as¹⁵NH₄ ^{+ 15}NO₃ ^– at sowing, tillering or stem elongation were compared with unfertilized microplots. Stubble from the previous rice crop was either incorporated, burnt without tillage, burnt then tilled or retained on the surface of untilled soil. Wheat grain yield ranged from 1.5 to 5.1 t ha^– and was closely related to N uptake. Plant accumulation of soil N averaged 36 kg N ha^–1 (LSD 5% = 10) on stubble-incorporation plots and 54 kg N ha^–1 on stubble-retention plots. Fertilizer N accumulation averaged 18 kg N ha^–1 (LSD 51% = 6) on stubble-incorporation plots and 50 kg N ha^–1 on stubble-retention plots. Tillage had little effect on burnt plots. Delaying N application from sowing until stem elongation increased average fertilizer N uptake from 26 to 39 kg N ha^–1 (LSD 5% = 6), but reduced soil N uptake from 50 to 37 kg N ha^– (LSD 5% = 10).Immobilization and leaching did not vary greatly between treatments and approximately one-third of the fertilizer was immobilized. Less than 1% of the fertilizer was found below a depth of 300 mm. Incorporating 9 t ha^–1 of rice stubble 13 days before wheat sowing reduced net apparent mineralization of native soil N from 37 to 3 kg ha^–1 between tillering and maturity. It also increased apparent denitrification of fertilizer N from an average 34 to 53 kg N ha^–1 (LSD 5% = 6). N loss occurred over several months, suggesting that denitrification was maintained by continued release of metabolizable carbohydrate from the decaying rice stubble. The results demonstrate that no-till systems increase crop yield and use of both fertilizer and soil N in intensive rice-based rotations.     

水稻产量形成的生理生态研究进展

水稻产量形态规律是水稻育种和栽培的基础理论，已成为作物学研究的热点课题。从产量构成、光合生产和源库结构方面简介了水稻产量形成规律的生理生态研究进展，分析了3个方面的研究特点和构成产量形成过程的网络关系。同时水稻产量形成是一个动态过程，水稻产量性状的最终表现决定于其生长发育过程中众多基因的表达、调控和相互作用，提出应用现代发育遗传学与分子生态学的理论和方法，深入研究水稻产量的形成规律。     

Detection of changes in taste of japonica and indica brown and milled rice (Oryza sativa L.) during storage using physicochemical analyses and a taste sensing system

Changes in the taste of japonica, hybrid, and indica brown and milled rice, stored for 10 months at low (5 degrees C, 65-70% relative humidity) and room temperatures were observed by physicochemical analyses and a novel method using a taste sensing system. During storage, some properties increased or decreased while others were fairly constant. The main taste components of cooked rice such as sweetness (sucrose) and umami tastes (glutamic acid and aspartic acid) were reduced during storage, whereas glucose and fructose increased. The increase of fat acidity and consequent decrease of the pH value of the cooking solution may contribute to the off-taste of cooked stored rice. A taste sensing system with 10 lipid membrane sensors was also used to classify new and old rice samples using principal component analysis. Fresh and room temperature stored japonica and indica rice could be clearly distinguished; however, it was not possible to differentiate the samples stored at low temperature.     

Asymmetric warming effects on N dynamics and productivity in rice (Oryza sativa L.)

Climate warming exhibits strong diurnal variations, with higher warming rates being observed at nighttime, which significantly affects rice (Oryza sativa L.) growth and grain yield. The objective of this study was to determine the effects of asymmetric warming (all-day warming, AW; daytime warming from 07:00 to 19:00, DW; nighttime warming from 19:00 to 07:00, NW, and a control, CK) on rice nitrogen (N) dynamics and productivity. Two rice bucket warming experiments were performed in Nanjing in Jiangsu Province, China, using the free air temperature increase (FATI) technique. The daily mean temperatures in the rice canopy in the AW, DW and NW plots were 2.0, 1.1 and 1.3ºC higher than those in the rice canopy in the CK plots, respectively. The results indicated that the total N accumulation of rice was 8.27–40.53% higher in the warming treatment than in the control during the jointing, anthesis and maturity stages. However, there was no significant difference detected among the three warming treatments. The warming treatment substantially decreased N translocation efficiency, leading to the retention of more N in the plant stems during grain filling. The warming treatment also decreased the N harvest index, N utilization efficiency based on grain yield and N utilization efficiencies based on biomass in both growing seasons. The warming treatment significantly increased the aboveground biomass (9.26–16.18%) in the jointing stage but decreased it (2.75–9.63%) in the maturity stage. Although DW increased the carbon (C) gain by photosynthesis and NW increased the C loss by night respiration, the daytime higher-temperature treatment affected rice photosynthesis and reduced its photosynthetic rate and product. This effect may be one of the primary reasons for the insignificant difference in the aboveground biomass between the DW and NW treatments. In the AW, DW and NW plots, the grain yield was reduced by an average of 10.07, 5.05 and 7.89%, respectively, across both years. The effective panicles and grains per spike tended to decrease in the warmed plots, whereas irregular changes in the 1000-grain weight were observed. Our results suggest that under the anticipated climate warming, rice productivity would further decline in the Yangtze River Basin.     

Influence of vesicular-arbuscular mycorrhizal fungi (Glomus etunicatum L.) on mobilization of zinc in wetland rice (Oryza sativa L.)

In a greenhouse trial, rice (Oryza sativa L.) cultivar Pusa Basmati-1 was grown in a Zn-deficient Typic Ustochrept soil from IARI farm, New Delhi, India. The experimental design included two rates of inoculation with vesicular-arbuscular mycorrhizal fungi (VAMF), Glomus etunicatum (nil and inoculated) and different combinations of organic (farmyard manure, FYM) and inorganic (NPK, ZnSO₄) fertilizers. The results revealed that a high intensity of root colonization in rice inoculated with G. etunicatum could be achieved by raising seedlings in P- and Zn-deficient soil in the nursery under aerobic conditions. Moreover, the VAMF that infected rice seedlings in the nursery also survived when the same seedlings were transplanted into pots under waterlogged conditions. The application of ZnSO₄ significantly increased the inflow of Zn to rice roots at the panicle-initiation stage (40 days after transplanting) relative to NPK. The former treatment also increased root length, root weight, root volume and total uptake of Zn and thereby increased the grain and dry matter yields. Alternatively, these variables were substantially enhanced by inoculating rice with the VAMF, G. etunicatum. The VAMF-colonized rice plants were more active in acquiring Zn from either added or native sources than non-colonized plants, and consequently the available-Zn content in soil was lower after the harvest of rice.     

Establishment of Azorhizobium caulinodans in the rhizosphere of wetland rice (Oryza sativa L.)

 Azorhizobium caulinodans strongly colonized the rhizosphere of rice plants after incorporation of Sesbania rostrata in a field trial throughout the growing season and during the fallow period until 19 weeks after incorporation of S. rostrata. A. caulinodans became well established in the rhizosphere (7.17 log cfu g^–1 dry rice root) and colonized subsequent S. rostrata test plants. Three traditional and three improved high-yielding rice varieties were inoculated with A. caulinodans under gnotobiotic conditions. In none of the combinations did acetylene reduction activity significantly increase. Ethylene production on colonized rice roots only started after the growth medium had been supplemented with an extra C source (0.1 to 0.25% Na-lactate). This indicates that the bacterial nitrogenase activity is limited by energy supply. Four possible inoculant-carriers (peat, coir dust, bagasse, rice straw) were compared for long-term survival of the bacterial strain. Independent of the storage temperature (26  °C or 4  °C), the survival of A. caulinodans in peat and coir dust was very high during a 12-month period (>8 log cfu g^–1 dry carrier), whereas the bagasse and rice straw carriers showed a serious decline from 3 months onwards. Received: 6 April 1999     

水稻雄蕊导管发育研究

本文以水稻粤泰保持系为材料，采用ATPase定位方法研究了单核至三核花粉期雄蕊导管的发育。单核边位花粉期，分化的导管胞质变浓厚、细胞核染色质浓缩、核转变为新月形并出现凋亡小体；此外，导管内物质也可以大分子形式直接撤离。单核边位晚期，雄蕊导管发育成熟。在二核和三核花粉期，导管内重新出现具有ATPase活性的物质，同样的现象也存在于农垦58s可育花药成熟导管中。以上结果暗示水稻雄蕊导管分化存在程序性死亡及非程序性死亡多种途径，水稻成熟导管内具有ATPase活性物质可能是一种普遍现象。     

Selection of efficient vesicular-arbuscular mycorrhizal fungi for wetland rice (Oryza sativa L.)

Summary We tested the response of the wetland rice cultivar Prakash to inoculation with ten vescular-arbucular mycorrhizal (VAM) fungi (three selected from the first screening and seven isolated from local paddy fields) in a pot experiment under flooded conditions in order to select the most efficient mycorrhizal fungi to inoculate the rice nursery. A sandy clay loam soil was used as the substrate, fertilized with the recommended N and K levels (100 kg N ha^–1 as ammonium sulphate and 50 kg K ha^–1 as muriate of potash) and half the recommended level of P (25 kg ha^–1 as super phosphate). The inoculation was made into dry nursery beds and the beds were flooded when the seedlings were about 25 cm high, in 15 days. Twenty-eight-day old seedlings were transferred to pots filled with well puddled soil flooded with 5 cm of standing water. Based on the increase in grain yield and total biomass, Glomus intraradices and Acaulospora sp. were considered efficient and suitable for inoculation into rice nurseries.     

Genotyping USDA rice (Oryza spp.) mini-core collection with functional markers for important agronomic traits

Genetic Resources and Crop Evolution - The USDA rice mini-core collection was established to capture the diversity of an entire collection of over 18,700 accessions of global origins for efficient...     

不同类型水稻籽粒灌浆的生理生化特性研究

以3个较大穗型的不同类型水稻品种(组合)“IR_(65600-85)”、“培矮64S/E32”、“Ⅱ优86”为材料,试验研究水稻籽粒灌浆特性及其有关生理生化活性变化结果表明,3个水稻的强势粒起始生长势均高于弱势粒,从而更早进入灌浆盛期;ADPG焦磷酸化酶活性强势粒高峰值均出现在花后6d,弱势粒峰值出现在花后12d;淀粉合成酶活性强势粒在花后0～18d高于弱势粒,尔后弱势粒高于强势拉,但“IR_(65600-85)”弱势粒后期活性仅弱高于强势粒,造成3个水稻的弱势粒灌浆不如强势粒,尤其是“IR_(65600-85)”弱势粒生理生化活性更低,其籽粒充实最差,结实率也最低。