Effects of leaf N concentration and leaf area index on determining rice tillering

Relative tillering rate(RTR)increased linear-ly with the increasing of leaf N concentration(NLV)has been already reported.To testwhether this relationship could be used toquantitatively explain the difference in tilleringamong a wide range of N application,field ex- periments were conducted at the IRRI farm,Los Banos,Laguna,the Philippines.Two in- dica cultivars,IR 72 and IR68284H wereused.For each cultivar,12 treatments includ- ing 4 N levels(0,60,120,and 180kgN·ha~(-1))and 3 transplanting spacing(30×20,20×20,and 10×20cm)were arranged in a ran-domized split-plot design with 4 replications.The N treatments were designated as mainplots and spacings as subplots.Fourteen-day-old seedlings were transplanted with 3seedlings per hill.The subplot area was 20m~2.Nitrogen fertilizer was applied as basal,atmidtillering,and at panicle initiation in threeequal splits.P,K,and Zn were applied asbasal at normal dosage.The field was flooded.Plant samples were taken every 7-14 d from 14d after transplanting to flower     

Inheritance of leaf color in purple rice

Two purple rice mutants OPL and PL184 were se lected from normal green rice lines Ketan Nangka and W6184 in 1988 and 1990 respectively. No segre gation was found in two sequent generations. When these two purple rice were crossed with each other. the F_1 and F_2 showed all purple color and no segregation occurred also, inferring that their leaf color maybe controlled by the same genotype. If these two purple rice lines crossed with other 23 normal green rice lines including 12 TGMS indica lines, 2 PGMS japonica lines, 2 WA indica lines. 1 BT indiea lines,4 convenLional indica varieties, and 2 conventional japonica varieties, their F_1 showed all normal green color.     

The absorption of^137 Cs in rice leaf

~(137)Cs is one of the fission products of nuclearfuel.~(137)Cs can translocate to crop and then getinto human body by food chain,harming hu-manbeing's health.Many works have reportedon the root absorption of ~(137)Cs,but few re-ported on the foliage absorption.     

Serological specificity of leaf streak pathogen of rice

The leaf streak of rice is one of the seedborne and quarantine bacterial disease in China. The rice seeds must be strictly inspected to prevent the disease from spreading. The serological test is a rapid and accurate method of identifying seedborne bacterial plant pathogens. But the specificity and thus reliability of any serological method depend first on the specificity of the antiserum. Therefore, a high specificity of antiserum is always required for and has become a key in detecting the leaf streak pathogen in rice seeds. The present study was conducted on the method of improving the specificity. Two group of antigen, the yellow and white proteins, were extracted from the cells of Xanthornonas oryzae pv. oryzicola by the methods of stepwise precipitation with ammonium sulfate and differential centrifugation. Antiserum A and B against the yellow and white proteins were each produced in white rabbit immunized with the proteins respectively. The tittle of the two antiserum were the same(1: 6400).     

Quantitative trait loci analysis of leaf morphology in rice

Ｔｈｅｌｅａｆｍｏｒｐｈｏｌｏｇｙｔｒａｉｔｓａｒｅｉｍｐｏｒｔａｎｔｃｏｍｐｏｎｅｎｔｐａｒｔｏｆｒｉｃｅｉｄｅｏｔｙｐｅ．Ｔｈｅｐｒｅｓｅｎｔｓｔｕｄｙｗａｓｃｏｎｄｕｃｔｅｄｗｉｔｈａｄｏｕｂｌｅｄｈａｐｌｏｉｄ（ＤＨ）ｐｏｐｕｌａｔｉｏｎｏｆ１１７ｌｉｎｅｓｄｅｒｉｖｅｄｆｒｏｍａｃｒｏｓｓｂｅｔｗｅｅｎａｎｉｎｄｉｃａｖａｒｉｅｔｙ，Ｚｈａｉｙｅｑｉｎｇ８（ＺＹＱ８）ａｎｄａｊａｐｏｎｉｃａｖａｒｉｅｔｙ，Ｊｉｎｇｘｉ１７（ＪＸ１７）．ＴｈｅＱＴＬｓｒｅｓｐｏｎｓｉｂｌｅｆｏｒａｒｅａ…     

Morphology and inheritance of a new rice leaf death mutant

A new mutant showing successive leaf death was selected in a mutmion populalion from an indica rice variety Zhongxian 3037 trealed with 94^Co-γ rays. The leaves of this rnutanl began lodie on the emergence of tlle third leaf tip, and all leaves died sooner alter flowering. Consequently,     

Factors affecting β carotene destruction in moist preserved leaf protein

Leaves are, and will probably remain, an important dietary source of carotene (provitamin A). There is enough of it in extracted leaf protein (LP) to make that a useful source. carotene is rapidly destroyed when LP, especially from young leaves, is preserved with salt. Destruction can be partly prevented by avoiding contamination with iron during preparation, by coagulating LP by heating rather than acidification, and by treatment with chelating agents. The unsaturated fatty acids in leaf lipids seem not to be involved in the destruction.     

Free proline accumulation in rice plants under different leaf water potential

Seedlings of drought-tolerance rice varieties Han 501 and Han A03, and the drought sensitive varieties Nanjing 11 and Yanjing 2 were raised in a paddy field and transplanted into pots at the age of 8 leaves. Water stress started at the tillering stage by holding water from 0 MPa of the soil water potential in pots till the leaves showed seriously wilting. Plants with well-watered were taken as control. Free proline content in rice leaves at different leaf water potential was measured. The levels of free proline accumulation in leaves under water stress were expressed by the relative proline content(RPC), the stress treatment/the control (100%).     

Quantitative trait loci analysis of chlorophyll content for flag leaf in rice

Ｃｈｌｏｒｏｐｈｙｌｌｃｏｎｔｅｎｔｓａｒｅｏｎｅｏｆｉｍｐｏｒｔａｎｔｐｈｙｓｉｏｌｏｇｉｃａｌｔｒａｉｔｓ，ｗｈｉｃｈａｆｆｅｃｔｐｈｏｔｏｓｙｎｔｈｅｓｉｓｉｎｐｌａｎｔｓ．ＴｈｅｒｅｗｅｒｅｓｉｇｎｉｆｉｃａｎｔｄｉｆｆｅｒｅｎｃｅｓｉｎｃｈｌｏｒｏｐｈｙｌｌｃｏｎｔｅｎｔｓｂｅｔｗｅｅｎＺｈａｉｙｅｑｉｎｇ８（ＺＹＱ８），ａｎｉｎｄｉｃａｖａｒｉｅｔｙａｎｄＪｉｎｇｘｉ１７（ＪＸ１７），ａｊａｐｏｎｉｃａｖａｒｉｅｔｙ（Ｔａｂｌｅ１）．Ｉｎ１１７ＤＨｌｉｎｅｓｏｆｔｈｅｃｒｏｓｓｏｆＺ…     

Plant regeneration of protoplasts isolated from suspension cells derived from leaf blade of Oryza sative

We used the leaf blade of rice (cultivars were Nonghu 6, Sugeng 2, Huyou 2 and Hanfeng) as initial material for protoplast culture, and a great number of regenerated plants were obtained.     

qRgls1.06, a major QTL conferring resistance to gray leaf spot disease in maize

Gray leaf spot(GLS)caused by Cercospora zeae-maydis and C.zeina is an extremely devastating leaf disease that limits maize production annually.The use of GLS-resistant maize hybrids is the most cost-effective approach for reducing losses.Resistance to GLS is quantitatively inherited in maize(Zea mays L.)and further sources of resistance remain to be analyzed.Here,we detected qRgls1.06,a major quantitative trait locus for GLS resistance in bin 1.06 that explained approximately 55%of the phenotype variance.Fine mapping over 2 consecutive years localized qRgls1.06 to a 2.38-Mb region.Homozygous qRgls1.06^WGR/WGR plants in DZ01 background displayed higher GLS resistance and 100-grain weight than DZ01 plants.The GLS responses of several susceptible elite inbred lines were improved by the introduction of qRgls1.06 by marker-assisted backcrossing.Our findings extend the understanding of the genetic basis of resistance to GLS and provide a set of resistant germplasm for genetic improvement of resistance to GLS in maize.     

Plant regeneration of protoplasts isolated from suspension cells derived from leaf blale of Oryza sative

We used the leaf blade of rice (cultivars were Nonghu 6, Sugeng 2, Huyou 2 and Hanfeng) as initial material for protoplast culture, and a great number of regenerated plants were obtained. Rice seeds were sterilized and germinated. The immature leaves were cut into 3-5 mm pieces when the third or forth leaf appeared. Leaf pieces were inoculated on MS medium with 2,4-D 4 mg/1, NAA 2mg/1 and IAA Img/1. After 2 wk culture, calli were induced and subcultured once or twice for multiplication. 3-5 g calli were transferred to the modified MS liquid medium with 2,4-D 2 mg/1 and KT 0.5mg/1 for suspension culture. Embryogenic cell suspension was established after 2 mo culture. The effect of the growth period of suspension cells on the     

The effects of topdressing at heading stage on translocation of assimilation from rice leaf to grain

Each 1g / pot of urea and K2SO4 were supplied to 15L pots containing four rice plants of two-line hybrids, W6154S / Tesan‘ai and W6154S/DF0(Ft), 5-7 d before and after heading. Basal fertilizers of each 2g/pot of urea, calcium superphosphate,     

QTL analysis of leaf photosynthetic rate and related physiological traits in rice(Oryza sativa L.)

Photosynthesis is one of the most important factors that influence the biomass and yield. Recently, more attention has been paid to genetic study on rice photosynthesis and rice breeding for the physiological traits related to high efficient photosynthesis. Chlorophyll content, stomatal resistance, and transpiration rate were very important physiological traits related to photosynthesis. But until now, no genetic study on these traits has been reported. A DH population derived from anther culture of ZYQ8/JX17, a typical indica/japonica hybrid was developed,     

Has long-term selection for yield in durum wheat also induced changes in leaf and canopy traits?

Over the last century, most of the genetic gain in the grain yield of Italian durum has been achieved by an increase in the harvest index and promotion of flowering time. We report the indirect effects of this long-term selection on a number of leaf and canopy traits associated with photosynthesis. In a 2-year experiment, using different sowing dates and nitrogen regimes, these characters were assessed for a set of 20 cultivars released between 1900 and 2000. Leaf area, specific leaf area, specific leaf nitrogen content and stomatal resistance were all negatively correlated with year of release, whereas canopy temperature showed a positive correlation. The substantial reduction in plant height, by which the rise in harvest index was achieved, was partly responsible for the rise in canopy temperature, acting via its effect on aerodynamic resistance. Senescence, when expressed in thermal time after anthesis, was delayed for the modern cultivars, and this delay could be associated with a greater quantity of nitrogen allocated to the grain. The association of senescence onset with earliness suggests a likely role of increased earliness in delayed senescence. The yield increase over time was correlated with a decrease in stomatal resistance and in specific leaf nitrogen content.     

Effects of 4PU-30 on leaf senescence and degration of protein and nucleic acid in rice

4PU—30[N—phenyl—'N—(2—chloro—4—pyridyl) urea] is a new type of plant growth regulator with cytokinin properties. It has been confirmed to delay rice leaf senescence effectively. In order to elucidate the physiological role of 4PU—30 in delaying senescence, the changes of protein, nucleic acid contents, and the related activities of degradative enzymes were studied. Shanyou 63, an indica hybrid rice was used for this experiment. In the in vitro experiment, two full—developed leaves from the top during heading stage were collected and cut into 5.0cm segments, They were floated on the surface of distilled water containing 0.1mg/14PU—30 and incubated in darkness at 30 C. The leaves floated on distilled water were used as control.It was observed that chlorophyll content in controlled leaves declined rapidly started from the second day and dropped by 93.4% on the 6th day while that in leaves treated with 4PU—30 declined by 41.4% only. During senescence, specific activities of hemoglobin—digesting     

Effects of S3307 on the photosynthesis,the activity of SOD,and MDA content of rice flag leaf

Ｕｎｉｃｏｎａｚｏｌ，（Ｅ）＿１＿（４＿ｃｈｌｏｒｏｐｈｅｎｙｌ）＿４，４＿ｄｉｍｅｔｈｙｌ＿２（１，２，４＿ｔｒｉａｚｏｌ＿ｌ＿ｙｌ）＿１＿ｐｅｎｔｅｎ＿３＿０１，ｎａｍｅｄＳ３３０７，ｉｓａｎｅｗｐｌａｎｔｇｒｏｗｔｈｒｅｔａｒｄａｎｔｔｈａｔｃａｎｒｅｔａｒｄｔｈｅ ｇｒｏｗｔｈｏｆ ｐｌａｎｔｓ，ｍａｋｅ ｐｌａｎｔｄｗａｒｆ，ｐｒｏｍｏｔｅｒｏｏｔａｎｄｔｉｌｌｅｒｇｒｏｗｔｈ，ｄｅｌａｙｔｈｅｓｅｎｅｓｃｅｎｃｅｏｆｌｅａｖｅｓ，ａｎｄｉｎｃｒｅａｓｅｔｈｅｎｅｔｐｈｏｔｏ ｓｙｎｔｈｅ…