Recent ipnc_xvi items

The effect of the AltSB gene on root growth in nutrient solution of isogenic sorghum hybrids

Sun, 4 Oct 2009 00:00:00 +0000

AlTSB, a major gene of the Multidrug and Toxic Compound Extrusion (Mate) family confers tolerance to aluminum toxicity in sorghum. This gene is a transporter gene that is responsible for the exudation of citric acid in the presence of toxic level of aluminum in the soil. The citrate complexes with the toxic aluminum forming a nontoxic compound. During the past several years, isogenic sorghum breeding lines, both cytoplasmic male-sterile lines (A and B-lines) and fertility restoring pollinator lines (R-lines) for this AlTSB gene have been developed at Embrapa Maize and Sorghum. These isogenic lines for AlTSB were used to develop sixteen isogenic sorghum hybrids with zero, one and two alleles for tolerance to aluminum toxicity. These sixteen hybrids are essentially genetically equal but with variation in the dose of the AlTSB allele. Seedlings of these isogenic hybrids were evaluated for root growth in nutrient solution with 0, 11, 20, 27 and 39μM aluminum for seven days at...

Potassium influenced phenylalanine ammonia-lyase, peroxidases and polyphenol oxidases in Fusarium graminearum infected maize (Zea mays L.)

Thu, 1 Oct 2009 00:00:00 +0000

Potassium (K) fertilizer is important for the reduction of many plant diseases, e.g., stalk rot of maize (Zea mays L.). However, the mechanism by which potassium promotes resistance to pathogens is not completely understood. Fusarium graminearum, which is the main pathogen causing stalk rot in maize, was selected to study the effect of potassium on phenylalanine ammonia-lyase (PAL; EC 4.3.1.5), peroxidase (POD; EC 1.11.1.7) and polyphenol oxidase (PPO; EC 1.14.18.1), at both the physiological and molecular level. Gene expression was quantified by real-time reverse transcription PCR (Q-RT-PCR) technology. The incidence of maize stalk rot was significantly reduced by K application. After inoculation with F. graminearum, the potassium concentration increased in susceptible organs. Potassium induced the expression of and sustained elevated activities of PAL, POD, and PPO when maize was inoculated with the pathogen. The expression of the corresponding genes was also stimulated by...

Biofortifying Brassica with calcium (Ca) and magnesium (Mg)

Tue, 15 Sep 2009 00:00:00 +0000

Billions of people worldwide consume insufficient calcium (Ca) or magnesium (Mg) for adequate health. Dietary Ca and Mg intakes can potentially be increased through crop biofortification. Recently, we reported sufficient natural genetic variation and heritability in a leafy crop plant (Brassica oleracea; C-genome, 1n=9; cabbage, cauliflower, kale etc.) to indicate that genetic biofortification is feasible in vegetable Brassica. We also reported loci affecting shoot Ca and Mg concentration (shoot-Ca and Mg). Here, we extend the previous study to explore the closely related species B. rapa (A-genome, 1n=10; Chinese cabbage, pak choi, a more tractable species genetically, and the amphidiploid species B. napus(AC-genome, 1n=19; canola/oilseed rape etc.). Wide variation in shoot/leaf-Ca and Mg occurs among all three species. Shoot/leaf-Ca and Mg is significantly and highly heritable. Quantitative trait loci (QTL) affecting shoot/leaf Ca and Mg concentration occur in potentially...

Is the Taste of Strawberry fruits (Fragaria x ananassa Duch.) affected by Ammonium and Nitrate Nutrition?

Fri, 4 Sep 2009 00:00:00 +0000

Strawberries are one of the most popular fruits. Since only tasteful fruits are attractive for the consumers the improvement of strawberry quality has been brought into focus over the last few years. The contributors to strawberry flavor are sugars, organic acids, and various volatile substances, making up the odor. Fructose, glucose, and sucrose represent 99% of the sugars. About 97% of the organic acids are citric acid and malic acid. In these studies we investigate the effect of the macronutrient nitrogen on the concentration of organic acids in strawberry plants and the fruits. Plant metabolism is differentially affected if nitrogen is taken up as NH4+ or NO3-. A high NH4+ uptake leads to a decreased pH in the cytoplasm and has to be stabilized by a proton excretion and by decarboxylation of organic acids by malic enzyme. In contrast, during NO3- reduction OH- is produced causing an increased cytosolic pH. This activates the enzyme PEP-caboxylase, which leads to an enhanced...

Integrated plant nutrient management on diversified cropping system in aqua-terrestrial ecosystem for yield potentiality, quality and rural sustainability

Wed, 2 Sep 2009 00:00:00 +0000

Balanced and integrated plant nutrient management is imperative in agricultural production system including its quality - more applicable to those of developing country in the world. Like arable land in wetland ecosystem, nitrogen and other essential key plant elements and its management is also an integral part for so many beneficial aquatic crops (food, non-food etc.). With this significant importance of IPNM, number of case studies were undertaken through TOT, TDET based integrated aquaculture research projects (NWDPRA, ICAR, DoLR, Govt. of India) suited to wetland ecosystem at different agro-climatic zones (NAZ, OAZ including Coastal zone) of Indian sub-continent. In field study, emphasize were paid for utilizing divergence of waste wetlands followed with adoption of improvised agro-techniques (IPN & its management) on nutritious, valuable and popular aquatic food crops [deep-water rice - Oryza sativa, water chestnut - Trapa bispinosa, makhana - Euryale ferox, water...

Nitrogen retranslocation during senescence in plants

Mon, 24 Aug 2009 00:00:00 +0000

Nitrogen remobilization is essential for nitrogen economy at the whole plant level. 15N tracing experiments showed that the Arabidopsis leaf to leaf N-remobilisation at vegetative stage was mainly determined by leaf senescence severity while N-remobilisation from rosette to seeds is depending on harvest index (Diaz et al. 2008). N-remobilisation efficiency to the seeds was higher in N limiting conditions (Lemaître et al. 2008). In order to investigate natural variation of nitrogen uptake and remobilisation in Arabidopsis, a core collection of accessions was grown at low (N-) and high (N+) nitrate supplies. Plants were labelled using 15N nitrate and traits measured (15N partition, nitrogen concentrations, remobilisation, biomass, yield, flowering). Globally, it was observed that the late-flowering plants had higher vegetative biomass, lower seed biomass and heavier seeds at both N+ and N- conditions. As a result, the late-flowering genotypes had lower harvest index (HI), higher...

Nitrogen (and phosphorus) nutrition of a woody plant and its root associates: a post-genomic perspective

Tue, 18 Aug 2009 00:00:00 +0000

Trees differ fundamentally from annual plant species in that they are adapted to survive on a long time-scale. The sequencing of the poplar genome and the use of appropriate functional tools offer an unprecedented opportunity to highlight key and specific mechanisms that characterize woody species. Most particularly, the isolation and characterization of complete sets of genes encoding transporters for inorganic / organic N and for P will bring fundamental knowledge that will be used to tackle changes in capacities for N and P uptake and assimilation under natural conditions. Additionally, under natural conditions the majority of trees are believed to have ectomycorrhizal (ECM) associations (intimate symbiotic association between fungi and roots), which can have a significant role in the worldwide nitrogen and/or phosphorus cycle. This mycorrhizal status relies 1) on efficient uptake processes by the fungal partner 2) on the bidirectional transfer of nutrients between the two...

Agronomic approaches in biofortification of food crops with micronutrients

Wed, 12 Aug 2009 00:00:00 +0000

Zinc (Zn) and iron (Fe) deficiencies are well-documented public health issue affecting nearly half of the world population. Developing countries are among the worst affected from Zn and Fe deficiencies which result in number of serious health complications, such as impairments in brain function and mental development, high susceptibility to deadly infectious disease and high risk for anemia. Recent reports indicate that, for example, Zn deficiency is responsible for death of nearly 450 000 children under 5-years old, annually. Very low concentrations and poor bioavailability of Zn and Fe in the commonly consumed foods seem to be the main reason for widespread occurrence of micronutrient deficiencies in human populations. Cereal-based foods are most commonly consumed foods and contribute up to 75 % of the daily calorie intake in the rural parts of the developing countries. Zinc and Fe deficiencies are also common micronutrient deficiencies in agricultural soils limiting both...

Phosphate Sensing in Root Development

Tue, 11 Aug 2009 00:00:00 +0000

Inadequate availability of inorganic phosphate (Pi) in the rhizosphere is a common challenge to plants, which activate metabolic and developmental responses to maximize Pi acquisition. The sensory mechanisms that monitor environmental Pi status and regulate root growth via altered meristem activity are unknown. We show that PHOSPHATE DEFICIENCY RESPONSE 2 (PDR2) encodes the single P5-type ATPase of Arabidopsis thaliana. PDR2 functions in the endoplasmic reticulum (ER) and is required for proper expression of SCARECROW (SCR), a key regulator of root patterning, and for stem cell maintenance in Pi-deprived roots. We further show that the multicopper oxidase encoded by LOW PHOSPHATE ROOT1 (LPR1) is targeted to the ER and that LPR1 and PDR2 interact genetically. Since the expression domains of both genes overlap in the stem cell niche and distal root meristem, we propose that PDR2 and LPR1 function together in an ER-resident pathway that adjusts root meristem activity to external...

Responses of Some Dwarf Bean (Phaseolus vulgaris L.) Genotypes Grown in Turkey to Zinc and Boron Applications

Mon, 10 Aug 2009 00:00:00 +0000

This study was conducted to determine the effects of boron (B) and zinc (Zn) applications on biomass, dry weight content and grain yield of 25 registered and local populations of dwarf bean genotypes tested. Plants were grown for 3 B and 3 Zn doses (0, 5, 10 mg kg-1 each). The trial was conducted in three replicates within a controlled glasshouse according to randomized plots factorial design. Results have shown that B and Zn applications considerably effect on the dwarf dry bean varieties in terms of biomass, dry weight and grain yield. From the genotypes used, Eskisehir-855, Karacasehir-90, Noyanbey, Terzibaba, Yakutiye, Fasulye sira, Yalova-17, Romano, Nazende, Seminis Gina, Yunus-90, Akman-98, Z¨ulbiye, Horoz fasulye and Kanada were found to be resistant to B deficiency while Sehirali-90, G¨oyn¨uk-98, Akdag, Sahin-90, ¨Onceler-98, Aras-98, Sarikiz, Magnum, May Gina and Efsane were the sensitive ones. The highest grain yield at 10 mg B kg-1 application was attained from...

Regulation of nitrogen nutrition at the whole tree level: biotic interactions in the rhizosphere of European beech forests

Mon, 10 Aug 2009 00:00:00 +0000

Despite high N requirements for growth and development, many forest trees have developed at sites with low N availability that are characterized by a largely closed ecosystem N cycle. Under such conditions trees have to compete with other organisms for the limited amount of N present. The competitors include the soil microflora, the natural regeneration, other understorey species, as well as competing tree species. In this contribution mechanisms of these competitive interactions are discussed in beech-dominated, deciduous forests that constitute the potential natural vegetation of Central Europe.

A mechanistic model for understanding pH effect on phosphorus availability in rhizosphere and bulk soil

Sat, 8 Aug 2009 00:00:00 +0000

While most studies have tried to assess phosphorus bioavailability based on phosphorus availability determined in the bulk soil, we question this approach which does not account for changes of P availability that occur in the rhizosphere. In this study, we combined the extraction of soil inorganic phosphorus (P) with CaCl2 or water and geochemical modelling in order to unravel the variations of P availability in the bulk soil and rhizosphere of durum wheat (Triticum turgidum durum L.) over a range of soil pH (pH ~ 4 to 9) chemically modified from initial pH. For this purpose, mechanistic models were used to simulate the adsorption of cations and anions by soil constituents with an additive approach. The geochemical codes accurately reproduced the concentration of extracted P by CaCl2 and water for both bulk soil and rhizosphere (RMSE = 5.3 and 10.6 µg.kg-1 for bulk and rhizosphere soil respectively). In rhizosphere, the effect of pH on P availability obtained by both extraction...

Investigation of vesicular – arbuscular mycorrhizal (VAM) on yield quantity and quality of sorghum cultivars under irrigation in arid area

Sat, 8 Aug 2009 00:00:00 +0000

Vesicular – arbuscular mycorrhiza (VAM)are beneficial microorganisms used in various industrial practices, such as mining, agriculture, and environmental rehabilitation. In the current experiments we studied the effects of different mycorrhizal fungi symbiosis with sorghum genotypes in the dryland area, Zabol , Iran. The results showed that there is significant differences between cultivar of sorghum and mycorrhiza on plant height, number of seed per spike, biomass, root colonization, plant growth and crop yield. Glomus etunicatum species were best mycorrhiza strain used in this research.

Delayed leaf senescence induces extreme drought tolerance in crop plants

Sat, 8 Aug 2009 00:00:00 +0000

Drought, the most prominent threat to agricultural production worldwide, accelerates leaf senescence, leading to a decrease in canopy size, loss in photosynthesis and reduced yields. On the basis of the assumption that senescence is a type of cell death program that could be inappropriately activated during drought, we hypothesized that it may be possible to enhance drought tolerance by delaying drought-induced leaf senescence through the stress-induced synthesis of cytokinins. We generated monocot and dicot transgenic plants expressing an isopentenyltransferase gene driven by pSARK, a stress- and maturation-induced promoter. Remarkably, the suppression of drought-induced leaf senescence resulted in outstanding drought tolerance as shown by, among other responses, vigorous growth following a long drought period that killed the control plants. The transgenic plants expressing pSARK-IPT maintained high water contents and retained photosynthetic activity (albeit at a reduced level)...

Impact on the fates of fertilizer Nitrogen of Different soil managements on black soil farmland

Sat, 8 Aug 2009 00:00:00 +0000

The use efficiency of fertilizer N decreased gradually during the grain production in black soil region in northeast China. Through a ten-year long experiment on wheat, corn and soybean, the evaluation on soil capacity of keeping and supplying N under three different soil management patterns using 15N have been conducted. The results showed there was no significant difference between the three management patterns in wheat removal of soil N, while the removal of fertilizer differed significantly; the residual rate of fertilizer was 12.84%,15.28% and17.51% respectively in pattern Ⅰ, pattern Ⅱ and pattern Ⅲ, and the loss rates of fertilizer in the three patterns were 57.93%, 49.49% and 42.07% respectively. Under the patternⅠmanagement, soil N removal by corn was less. There were no significant differences on the soil N removal between pattern Ⅱand pattern Ⅲ. The loss ratios were 54.19%, 46.61% and 39.94% in patternⅠ, Ⅱ and Ⅲ respectively. The order of utilizing N efficiency of...

Metal distribution in rice seeds during the germination

Sat, 8 Aug 2009 00:00:00 +0000

To investigate the flow of the nutrients iron (Fe), zinc (Zn), manganese (Mn), and copper (Cu) during rice seed germination, we performed microarray analysis to examine the expression of genes involved in metal transport. Many kinds of metal transporter genes were strongly expressed and their expression levels changed during rice seed germination. Furthermore, imaging of the distribution of elements (Fe, Mn, Zn, and Cu) was carried out using Synchrotron-based X-ray microfluorescence at the Super Photon ring-8 GeV (SPring-8) facility. The change in the distribution of each element in the seeds following germination was observed by in vivo monitoring. Iron, Mn, Zn, and Cu accumulated in the endosperm and embryos of rice seeds, and their distribution changed during rice seed germination. The change in the patterns of mineral localization during germination was different among the elements observed.

Does jasmonic acid control the maize shoot growth during the first phase of salt stress?