Increased Plant Dry Weight Research Articles

Efektivitas Frekuensi dan Volume Penyemprotan Daun dengan Agens Hayati Filosfer dalam Meningkatkan Pertumbuhan Tanaman dan Hasil Padi

ABSTRACT<br /><br />Increased of plant productivity in field determined by the use of quality seed from improved variety. The purpose of this research was to study the effect of frequency and volume of phyllosphere biological agents by foliar spray on rice plant infected by Xanthomonas oryzae pv. oryzae (Xoo) in improving plant growth, production of rice seed, and controlling bacterial leaf blight (BLB). This research was conducted at Seed Health Laboratory, Department of Agronomy and Horticulture, Bogor Agricultural University, and Muara Experimental Field, Rice Research Institute, March through September 2014. The experiment was conducted using a randomized complete block design with two factors, and replicates as blocks. The first factor was five levels of frequency of spraying with biological agents: P0 = control, P1 = Xoo seed inoculated then invigorated with biomatriconditioning, P2 = Xoo inoculated seed, then biomatriconditioned, and the plants were sprayed with phyllosphere biological agents F112 once, P3 = as P2, and the plants were sprayed with F112 twice, and P4 = as P2, and the plants were sprayed with F112 three times. The second factor was three levels of spray volume: i.e., 300, 400, and 500 L ha-1. Result of this experiment revealed that biomatriconditioning with rhizobacteria P. diminuta A6 and B. subtilis 5/B improved field emergence and seedling dry weight. Seeds applied with biomatriconditioning then followed by foliar spray with phyllosphere bacteria F112 at 40, 60, and 80 days after transplanting effectively reduced severity of BLB, increased plant dry weight and seed yield. All treatments increased yield as compared to untreated control. Volume of foliar application showed no significant difference, therefore, the lowest volume of 300 L ha-1 was recommended. <br /><br />Keywords: Bacillus subtilis 5/B, biomatriconditioning, Pseudomonas diminuta A6, Xanthomonas oryzae pv. oryzae

Effects of Selected Diazotrophs on Maize Growth.

Laboratory, greenhouse, and field experiments were conducted at the University of KwaZulu-Natal, Pietermaritzburg, South Africa in the 2010/2011 and 2011∖2012 seasons to study the effects of eight strains of diazotrophic bacteria on the growth and yield of maize. Maize seeds were treated with Bacillus megaterium (V16), Pseudomonas sp. (StB5, A3, A6, and A61), Burkholderia ambifaria (V9), Enterobacter cloacae (L1) and Pantoea ananatis (LB5), aiming to stimulate plant growth, and maintain or increase yields while reducing the need for N fertilization. All the diazotrophic bacteria increased germination of maize seed, and Pseudomonas sp. (StB5) and B. megaterium (V16) significantly increased shoot length. Pseudomonas sp. (StB5), B. megaterium (V16), E. cloacae (L1), B. ambifaria (V9), and Pseudomonas sp. (A3) very significantly increased root length and seed vigor index. Under greenhouse conditions, plants treated with diazotrophic bacteria developed more leaf chlorophyll and greater dry weight, albeit not significantly (n.s.). In a field trial in 2010/2011, application of the best five diazotrophic bacteria, with or without 33% N-fertilizer, had no significant effect on germination, grain yield, dry weight, plant height and leaf chlorophyll. In the 2011/2012 growing season, at 60 days after planting (DAP), all the diazotrophic bacteria increased plant dry weights to equal that of the fertilized control (33%N-fertilizer) (n.s.). After inoculation with the diazotrophs alone increased plant heights (n.s.), and chlorophyll contents (n.s.). With the addition of 33%N-fertilizer at planting, the diazotrophs still caused increases of chlorophyll content relative to the control with 33%N (n.s.). It may be concluded that the tested diazotrophs alone may be beneficial for use on maize growth.

Screening of Rhizospheric Actinomycetes for Various In-vitro and In-vivo Plant Growth Promoting (PGP) Traits and for Agroactive Compounds.

In this study 98 rhizospheric actinomycetes were isolated from different wheat and tomato fields, Punjab, Pakistan. The isolates were characterized morphologically, biochemically, and genetically and were subjected to a comprehensive in vitro screening for various plant growth promoting (PGP) traits. About 30% of the isolates screened were found to be the promising PGP rhizobacteria (PGPRs), which exhibited maximum genetic similarity (up to 98–99%) with different species of the genus Streptomyces by using16S rRNA gene sequencing. The most active indole acetic acid (IAA) producer Streptomyces nobilis WA-3, Streptomyces Kunmingenesis WC-3, and Streptomyces enissocaesilis TA-3 produce 79.5, 79.23, and 69.26 μg/ml IAA respectively at 500 μg/ml L-tryptophan. The highest concentration of soluble phosphate was produced by Streptomyces sp. WA-1 (72.13 mg/100 ml) and S. djakartensis TB-4 (70.36 mg/100 ml). All rhizobacterial isolates were positive for siderophore, ammonia, and hydrogen cyanide production. Strain S. mutabilis WD-3 showed highest concentration of ACC-deaminase (1.9 mmol /l). For in-vivo screening, seed germination, and plant growth experiment were conducted by inoculating wheat (Triticum aestivum) seeds with the six selected isolates. Significant increases in shoot length was observed with S. nobilis WA-3 (65%), increased root length was recorded in case of S. nobilis WA-3 (81%) as compared to water treated control plants. Maximum increases in plant fresh weight were recorded with S. nobilis WA-3 (84%), increased plant dry weight was recorded in case of S. nobilis WA-3 (85%) as compared to water treated control plants. In case of number of leaves, significant increase was recorded with S. nobilis WA-3 (27%) and significant increase in case of number of roots were recorded in case of strain S. nobilis WA-3 (30%) as compared to control plants. Over all the study revealed that these rhizospheric PGP Streptomyces are good candidates to be developed as bioferlizers for growth promotion and yield enhancement in wheat crop and can be exploited for the commercial production of different agro-active compounds.

Metal resistant and phosphate solubilizing bacterium improves maize (Zea mays) growth and mitigates metal accumulation in plant

Abstract The current study focuses on plant promoting and metal detoxifying properties of a heavy metal resistant bacterium with phosphate (P) solubilizing and Indole-3-acetic acid (IAA) producing capabilities. The bacterium was a strain of Pseudomonas putida Ws3 selected from an agricultural land irrigated with sewage water. It could solubilize P up to 300 mg/l and produce IAA up to 200 µg/l in seven days at optimal culture condition, i.e. NaCl (0.5%), KCl (0.01–0.04%), Mg/Cl2 (0.3%) and NH4Cl (0.5%) and 30 °C. Regarding soluble P and IAA concentrations in Pikovskaya (PVK) liquid media, the activity of the bacterium declined in media containing CuCl2 (500 mg/l), PbCl2 (300 mg/l) or CdCl2 (300 mg/l). The metals at elevated levels limited the bacterial population growth in a soil-like substrate supporting roots of a model plant (maize or Zea mays). Weekly bacterial inoculation to the substrate for 40 days alleviated the condition for plant growth, led to increased plant dry weight and decreased the metals accumulated in plant with large effect sizes in the shoot (g=1.49) and root (g=1.36).

Management of Meloidogyne incognita and Macrophomina phaseolina by Graphene Oxide on Lens culinaris

Effect of Graphene oxide (GO) was observed on Meloidogyne incognita and Macrophomina phaseolina and on the growth of lentil in pot experiment. Treatment of plants with 10 ml solution of GO with 125, 250 and 500 ppm concentration caused a significant increase in plant dry weight over control. Inoculation of plants with M. incognita or M. phaseolina caused a significant reduction in plant dry weight over uninoculated control. Treatment of plants with 125, 250 and 500 ppm GO and subsequent inoculation with M. incognita or M. phaseolina caused a significant increase in plant dry weight over plants inoculated without GO pretreatment. Treatment of 500 ppm GO caused a greater increase in plant dry weight of M. incognita or M. phaseolina inoculated plants followed by 250 ppm and 125 ppm. Numbers of nodules per root system were high in plants without pathogen. Inoculation of M. incognita or M. phaseolina caused reduction in nodulation. However, treatment of GO in all the three concentrations had no significant effect on nodulation in plants both with and without pathogens. Treatment of GO resulted in reduced galling, nematode multiplication and root-rot index. Greater reduction in galling, nematode multiplication and root-rot index were observed in plants treated with 500 ppm GO followed by 250 ppm and 125 ppm. Indices were reduced to 4, 3 and 2, respectively, when plants with M. phaseolina were treated with 125, 250 and 500 ppm GO. This study shows that the use of GO is useful for the management of M. incognita and M. phaseolina on lentil.

Role of chitosan in improving salinity resistance through some morphological and physiological characteristics in fenugreek (Trigonella foenum-graecum L.)

Soil salinity is a serious environmental problem that has negative impacts on growth and production of plants. On the other hand, application of chitosan has recently been increased to enhance the resistance to different stresses, such as salinity. In order to study the effect of chitosan seed-priming on alleviation of salinity stress in fenugreek (Trigonella foenum-graecum L.) a factorial experiment, based on completely randomized design with three replications, was conducted in 2014 in the Research Greenhouse of University of Zabol. Chitosan pretreatment, taken as the first factor, was applied at three levels (0, 0.5 and 1 g/l) and sodium chloride (NaCl) was the second factor at four levels (0, 50, 150 and 250 mM). Before planting, the seeds were soaked for 6 hours in the chitosan solutions. NaCl was applied to the plants by irrigation water (after 2-leaf stage), with 3-day intervals. Results indicated that increasing salinity stress reduced growth characteristics, content of photosynthetic pigments, leaf relative water content, chlorophyll index and increased the amount of anthocyanin and proline. Seed-pretreatment by application of 0.5 mg/L chitosan, under salinity stress, increased plant dry weight, length of stem and roots, and leaf relative water content, as compared to the control treatment. In addition, under the salinity level of 250 mM, application of 1 g/L chitosan increased chlorophyll a, chlorophyll b and carotenoids content by 43.7, 65.4 and 28 percent, respectively, as compared to the control treatment. The highest amount of anthocyanin was found in the 1 g/L chitosan treatment. In general, these results suggested that in salt-affected areas, seed pretreatment by application of chitosan could be utilized efficiently for reducing the salinity stress on leaf relative water content and photosynthetic pigments, and better growth and stablishment of fenugreek plant.

Role of Arbuscular Mycorrhiza in Alleviating Salinity Stress in Wheat (Triticum aestivum L.) Grown Under Ambient and Elevated CO2

AbstractPlant growth and development are influenced by future elevated atmospheric CO2 concentration and increased salinity stress. AM (arbuscular mycorrhiza) symbiosis has been shown to improve plant growth and resistance to environmental stresses. The aim of this study was to investigate the potential role of AM fungus in alleviating salinity stress in wheat (Triticum aestivum L.) plants grown under ambient and elevated CO2 concentrations. Wheat plants inoculated or not inoculated with AM fungus were grown in two glasshouses with different CO2 concentrations (400 and 700 μmol l−1) and salinity levels (0, 9.5 and 19.0 dS m−1). Results showed that salinity stress decreased and elevated CO2 increased AM colonization. AM inoculation increased plant dry weight under elevated CO2 and salinity stress. Stomatal conductance, density, size and aperture of AM plants were greater than non‐AM plants. AM fungi enhanced NUE by altering plant C assimilation and N uptake. AM plants had higher soluble sugar concentration and [K+]: [Na+] ratio compared with non‐AM plants. It is concluded that AM symbiosis improves wheat plant growth at vegetative stages through increasing stomatal conductance, enhancing NUE, accumulating soluble sugar, and improving ion homeostasis in wheat plants grown at elevated CO2 and salinity stress.

Amelioration of salt stress in chickpea (Cicer arietinum L.) by coinculation of ACC deaminase-containing rhizospheric bacteria with Mesorhizobium strains

Chickpea is a major legume crop grown in the semi-arid tropics and its yields are adversely affected by salinity. In this study, 55 rhizobacterial isolates obtained from the chickpea rhizosphere soil were screened for their salt tolerance. At 3% NaCl concentration, 41.8% rhizobacterial isolates formed colonies varying from 0.5-10 mm size and only 10.9 per cent isolates showed growth at 4% NaCl concentration. Significant growth on ACC supplemented medium plates was observed in 32.7% rhizobacterial isolates. Coinoculation studies with ACC+ as well as ACC- Mesorhizobium and rhizobacterial isolates were made on chickpea under chillum jar conditions containing sloger’s broth with salt (EC, 4dS/m) and without salt. Coinoculation of Mesorhizobium isolate MBD26 (ACC+) and rhizobacterial isolate RHD18 (ACC+) formed 59 nodules/plant and caused 112.9% increase in plant dry weight as compared to uninoculated control plants at 50 days of plant growth, whereas in the presence of salt, only 31.2% increase in plant dry weight was observed in comparison to uninoculated plants. At 80 days of plant growth, coinoculation of Mesorhizobium isolate MBD26 (ACC+) with rhizobacterial isolate RHD18 (ACC+) further increased the nodule number (78 nodules/plant) and 141.9% increase in shoot dry weight was observed as compared to uninoculated plants. Thus, it was concluded that coinoculation of ACC+ Mesorhizobium and rhizobacterial isolates showed more stimulatory effect on nodulation and plant biomass under normal and salt amended treatments.

Nitrogen Fertigation Rates Affect Stored Nitrogen, Growth, and Blooming in Iris germanica ‘Immortality’

Tall bearded (TB) iris (Iris germanica L.) has great potential as a specialty cut flower due to its fragrance and showy, multicolor display; however, limited research has been reported on optimal nitrogen (N) nutrient management for TB iris. The objectives of this study were to investigate the effects of N fertilizer rate on plant growth and flowering of ‘Immortality’ iris and determine the influence of both stored N and spring-applied N fertilizer on spring growth and flowering. On 14 Mar. 2012, rhizomes of ‘Immortality’ iris were potted in a commercial substrate with no starter fertilizer. Plants were fertigated with 0, 5, 10, 15, or 20 mm N from NH4NO3 twice per week from 28 Mar. to 28 Sept. 2012. In 2013, half of the plants from each of the 2012 N rate were supplied with either 0 or 10 mm N from 15NH415NO3 twice per week from 25 Mar. to 7 May 2013. Growth and flowering data including plant height, leaf SPAD, number of fans and inflorescence stems, and length of inflorescence stem were collected during the growing season. Plants were harvested in Dec. 2012 and May 2013 to measure dry weight and N concentration in leaves, roots, and rhizomes. Results showed higher 2012 N rates increased plant height, leaf SPAD reading, and number of inflorescence stems at first and second blooming in 2012. Greater 2012 N rates also increased plant dry weight and N content in all structures, and N concentration in roots and rhizomes. Rhizomes (58.8% to 66.3% of total N) were the dominant sink for N in Dec. 2012. Higher 2012 N rates increased plant height, number of fans, and the number of inflorescence stems at spring bloom in 2013. In May 2013, N in leaf tissue constituted the majority (51% to 64.3%) of the total plant N. Higher 2012 N rates increased total dry weight, N concentration, and N content in all 2013 15N rates; however, leaf dry weight in all plants was improved by 2013 15N rate. Percentage of tissue N derived from 2013 15N (NDFF) decreased with increasing 2012 N rate. New spring leaves were the dominant sink (56.8% to 72.2%) for 2013 applied 15N. In summary, ‘Immortality’ iris is capable of a second blooming in a growing season, this second blooming dependent on N fertilization rate in current year. A relatively high N rate is recommended to produce a second bloom.

Exploring the efficacy of wastewater-grown microalgal biomass as a biofertilizer for wheat.

Microalgae possess the ability to grow and glean nutrients from wastewater; such wastewater-grown biomass can be used as a biofertilizer for crops. The present investigation was undertaken to evaluate two formulations (formulation with unicellular microalgae (MC1) and formulation with filamentous microalgae (MC2); T4 and T5, respectively), prepared using wastewater-grown microalgal biomass, as a biofertilizer (after mixing with vermiculite/compost as a carrier) in wheat crop (Triticum aestivum L. HD2967) under controlled conditions. The highest values of available nitrogen (N), phosphorus (P), and potassium (K) in soil and nitrogen-fixing potential were recorded in treatment T5 (75% N + full-dose PK + formulation with filamentous microalgae (MC2). Microbial biomass carbon was significantly enhanced by 31.8-67.0% in both the inoculated treatments over control (recommended dose of fertilizers), with highest values in T4 (75% N + full-dose PK + formulation with unicellular microalgae (MC1)). Both the microalgal formulations significantly increased the N, P, and K content of roots, shoots, and grains, and the highest total N content of 3.56% in grains was observed in treatment T5. At harvest stage, the treatments inoculated with microalgal formulations (T4 and T5) recorded a 7.4-33% increase in plant dry weight and up to 10% in spike weight. The values of 1000-grain weight showed an enhancement of 5.6-8.4%, compared with T1 (recommended doses of fertilizers). A positive correlation was observed between soil nutrient availability at mid crop stage and plant biometrical parameters at harvest stage. This study revealed the promise of such microalgal consortia as a biofertilizer for 25% N savings and improved yields of wheat crop.

Effect of biochars and microorganisms on cadmium accumulation in rice grains grown in Cd-contaminated soil.

Cadmium (Cd) contaminated in rice grains is a serious problem because most Asians consume rice on a daily basis. Rice grown in Cd-contaminated soil normally did not have high concentration of Cd. However, soil samples used in this study had high concentrations of Cd. The purpose of this study was to clearly see the effects of biochar and microorganism addition in rice growing in Cd-contaminated soil. The initial Cd concentration in Cd-contaminated soil used in this study was about 650 mg kg(-1). Cadmium concentration in rice plants grown in Cd-contaminated soil with the addition of 1% (w/w) different biochars such as sawdust fly ash (SDFA), bagasse fly ash (BGFA), and rice husk ash (RHA) was investigated. The results showed that SDFA was the best biochar in terms of reducing cadmium accumulation in rice grains when compared to BGFA and RHA under the same conditions. In addition, rice plants grown in Cd-contaminated soil with the addition of various nonpathogenic microorganisms, such as Pseudomonas aeruginosa, Bacillus subtilis, and Beauveria bassiana were also studied. The results showed that the addition of 2% (v/v) microorganisms can reduce Cd accumulation in grains. It was found that grains obtained from Cd-contaminated soil with the addition of P. aeruginosa had the lowest cadmium concentration compared to the ones from soil amended with other strains. This was due to the fact that P. aeruginosa adsorbed more Cd itself into its cells than other strains. The rice plants grown in Cd-contaminated soil with the addition of biochars and microorganisms were also compared. The results showed that adding 2% (v/v) microorganisms seemed to reduce Cd accumulation in rice grains better than adding 1% (w/w) biochars. In addition, the amounts of calcium and magnesium in rice grains and the dry weight of plant in Cd-contaminated soil amended with P. aeruginosa were the highest in comparison to other microorganisms, biochars, and the soil without any amendments (Cd-soil control). It might be possible that microorganisms can cause leaching of Ca, Mg, etc. from contaminated soil and compete with Cd to be uptaken by plants. This would cause the increase in plant dry weight and higher mineral nutrients accumulation in grains. Both biochars and microorganisms are suitable for reducing the amount of Cd in rice grains. The application should depend on farmers, biochars available in nearby areas, etc. Therefore, microorganisms and biochars can be used to solve the problem of cadmium contamination in rice grains.

Respons Pertumbuhan Vegetatif Jagung Di Tailing Tambang Timah Terkontaminasi Kadmium Setelah Inokulasi Bakteri Indogenus

Contaminant levels of cadmium (Cd) in tin mine tailings often exceeds the upper limit. Relatively high Cd content might decrease crop yields and threatened food chain. Bioremediation by using indigenous microbes to lower soil Cd shoud be done prior to use tailings for cultivation. The objective of this experiment was to obtain information about the capacity of indigenous bacterias to induce bacterial proliferation in the rhizosphere, corn growth during the early vegetative stage and change the concentration of Cd in soil and plants. Pot experiment was set up in a Randomized Block Design consist of several combination of two bacterial isolates and their doses. Maize seeds were sown in tailings from the mine site on the island of Bangka and inoculated with indigenous bacteria. The results showed that the bacterial inoculation increased number of bacteria in the rhizosphere and plant height, but only isolates BKH1 with a dose of 5 mL/plants that increased plant dry weight. Soil Cd content decreased when inoculated by bacteria although not statistically significant, while the effect of inoculation on plant Cd uptake was inconsistent.

Cr Stable Isotope Fractionation in Arbuscular Mycorrhizal Dandelion and Cr Uptake by Extraradical Mycelium

As common soil fungi that form symbioses with most terrestrial plants, arbuscular mycorrhizal (AM) fungi play an important role in plant adaptation to chromium (Cr) contamination. However, little information is available on the underlying mechanisms of AM symbiosis on plant Cr resistance. In this study, dandelion (Taraxacum platypecidum Diels.) was grown with and without inoculation of the AM fungus Rhizophagus irregularis and Cr uptake by extraradical mycelium (ERM) was investigated by a compartmented cultivation system using a Cr stable isotope tracer. The results indicated that AM symbiosis increased plant dry weights and P concentrations but decreased shoot Cr concentrations. Using the Cr stable isotope tracer technology, the work provided possible evidences of Cr uptake and transport by ERM, and confirmed the enhancement of root Cr stabilization by AM symbiosis. This study also indicated an enrichment of lighter Cr isotopes in shoots during Cr translocation from roots to shoots in mycorrhizal plants.

Characterising the rhizospheric soil niches of beach plum (Prunus maritima) colonised by arbuscularmycorrhizal fungi and/or phosphate-solubilising fungi when grown under NaCl stress

SummaryThe objective of this work was to study the effects of inoculation with an arbuscular mycorrhizal fungus (AMF), Glomus mosseae, and/or a phosphate-solubilising fungus (PSF), Mortierella sp. SM-1, on the rhizospheric niche of beach plum (Prunus maritima) when grown under 1% (w/v) NaCl stress. Salinisation adversely affected colonisation by AMF, microorganism populations, available-P, and hydrolysable-N concentrations in the soil, as well as phosphatase, urease, and proteinase activities in the rhizospheric niche of beach plum, resulting in a significant reduction (P 0.05) in the dry weight (DW) of the plants. Plants inoculated with AMF and/or PSF avoided these adverse changes. Combined inoculation with AMF and PSF promoted AMF colonisation, increased plant DWs, and significantly increased bacterial and actinomycete numbers on the root surface and in roots, and nitrogen-fixing bacterial numbers on the root surface of beach plum plants. Dual inoculation with AMF plus PSF also resulted in significantly higher phosphatase, urease, and protease activities, and higher concentrations of available-P and hydrolysable-N in rhizosphere soil than following a single inoculation with AMF or PSF. After 90 d of 1% (w/v) NaCl stress, soil pH values in the rhizosphere of beach plum plants co-inoculated with AMF plus PSF were significantly lower than in the rhizosphere of plants inoculated with AMF or PSF alone.We conclude that inoculation with AMF plus the application PSF synergistically improved the micro-ecological environment and increased soil fertility in the rhizosphere of beach plum, which improved the tolerance of these plants to saline stress.

Perlakuan Agens Hayati untuk Mengendalikan Hawar Daun Bakteri dan Meningkatkan Produksi Benih Padi Sehat

ABSTRACT The research objectives were to evaluate biological agent treatments in controlling bacterial leaf blight (BLB) and increasing plant growth and seed production of rice. The experiment was conducted in the greenhouse and field using the same experimental design (randomized block design with two factors) and three replications. The first factor was seed treatments, i.e. negative control, positive control, streptomycin sulphate 0.2%, Pseudomonas diminuta + Bacillus subtilis, matriconditioning + streptomycin sulphate 0.2%, and matriconditioning + P. diminuta + B. subtilis. Spraying plants (second factor): untreated control, streptomycin sulphate 0.2%, biological agent F112, biological agent F198, and biological agent F57. In the greenhouse, matriconditioning + P. diminuta + B. subtilis improved seed germination, plant height, and plant dry weight. Spraying plants with biological agent F112 increased plant dry weight. Meanwhile, matriconditioning + P. diminuta + B. subtilis followed by spraying plants with biological agent F112 reduced the BLB severity. In the field, matriconditioning + P. diminuta + B. subtilis improved seedling dry weight. Matriconditioning + P. diminuta + B. subtilis and spraying plants with biological agents F112 controlled BLB and increased plant growth. However, all treatments were not able to increase healthy seed production. Keywords: matriconditioning, seed treatment, phyllosphere biological agents, Xanthomonas oryzae pv. oryzae

Vegetative Growth of Three Southern Highbush Blueberry Cultivars Obtained from Micropropagation and Softwood Cuttings in Two Florida Locations

Field performance of southern highbush blueberry (Vaccinium corymbosum L. interspecific hybrids) cultivars Emerald, Jewel, and Primadonna derived from softwood cuttings (SW) and tissue culture (TC) was evaluated in Citra and Haines City, FL, in 2010–12. Both fields were planted in Apr. 2010 on sandy soil amended with pine bark. Plant height and width were recorded at both locations, from which plant canopy volume was calculated. Additionally, whole plants were harvested at planting and after the first growing season, after the first fruit harvest, and after the second growing season. Average plant height and width, number of major canes, and total shoot number were determined at each sampling date. Dry weights for roots, crowns, canes, shoots, and leaves were obtained. Although propagation method affected plant canopy volume during the first season, no effects were observed by the end of the second growing season. At planting and after the first and second growing seasons, TC plants of the three cultivars had more major canes. Total shoot number per plant was greater for TC ‘Jewel’ at all dates but ‘Emerald’ TC plants had more shoots only at planting and after the first growing and harvest seasons. Tissue culture resulted in increased plant dry weights of ‘Jewel’ and ‘Emerald’ after the first and second growing seasons. There were no significant differences in total number of shoots or plant dry weight between TC and SW-derived ‘Primadonna’ plants at any point during the study.

Analysing the colonisation of inoculated cyanobacteria in wheat plants using biochemical and molecular tools

The modulation in physiological and metabolic attributes associated with colonisation by cyanobacteria in wheat has been little explored. In the present investigation, the performance of six selected cyanobacterial strains was evaluated with wheat (variety HD2687). The fresh weight of plants, measured after 2 weeks, exhibited a 30–60 % increase, while 14–40 % increase in plant dry weight was also recorded, as compared to uninoculated control. The nitrogen-fixing potential (expressed as acetylene-reducing activity or ARA) was 20-fold higher in the treatment involving inoculation of Anabaena laxa RPAN8 as compared to that in the uninoculated control. The inoculation of Calothrix sp. RPC1 brought about a more than 90 % increase in endoglucanase activity and root chlorophyll. Comparison of DNA fingerprints (highly iterated palindrome (HIP)-TG profiles) of wheat roots with those of corresponding pure cultures revealed a high degree of similarity, confirming the colonisation. Significant correlation of plant parameters with nitrogen-fixing potential and growth attributes and fingerprints of cyanobacteria from roots further illustrated the novelty of our results. This represents a first report on understanding hydrolytic enzyme-mediated colonisation of cyanobacteria on roots of wheat plants using plant growth parameters and DNA fingerprints. Such synergistic combinations of cyanobacterium and wheat can lead to savings of nitrogen and increased yields, besides being a prelude to generating nitrogen-independent wheat plants.

Cycocel Priming and Foliar Application Affect Yield Components of Rapeseed (Brassica Napus L.)

ABSTRACT A factorial based on RCBD experiment was conducted to evaluate the effects of priming and foliar spray of cycocel on rapeseed yield components. Treatments were included; seed priming (0, 600, 900, 1200, 1500 μM) and foliar spray (0, 600, 1200 μM) with cycocel at development stage of flower buds. The results revealed that seed priming with cycocel significantly increased emerged plant number per plot, silique dry weight in the main stems and branches, plant dry weight, branches number, silique number in the main stems and branches, seed number in branches, 1000 seeds weight, and seed yield in non-stress conditions. Foliar application with cycocel also increased plant dry weight, 1000 seeds weight in branches, harvest index and seed yield. Moreover, interaction effect of priming and foliar application of cycocel increased plant dry weight and 1000 seeds weight with branches. CCC foliar application during the early stages of reproductive stage went to elevated plant dry weight and 1000 seeds weight in auxiliary branches and, also increased harvest index and grain yield. Mean comparison and interaction effects of traits also revealed that, appropriate levels of CCC had the meaningful effects on any agronomic and physiological trait. However, the most meaningful impact in most traits was traced in case with primed seed with 900 and 1500 μM CCC. Overall, owing to the present data, CCC priming under both normal and harsh conditions may raise the germination related traits, seedling establishment, plant growth and ultimately may goes to increased yield.

Regulation of hormonal responses of sweet pepper as affected by salinity and elevated CO2 concentration

This study examines the extent to which the predicted CO2 -protective effects on the inhibition of growth, impairment of photosynthesis and nutrient imbalance caused by saline stress are mediated by an effective adaptation of the endogenous plant hormonal balance. Therefore, sweet pepper plants (Capsicum annuum, cv. Ciclón) were grown at ambient or elevated [CO2] (400 or 800 µmol mol(-1)) with a nutrient solution containing 0 or 80 mM NaCl. The results show that, under saline conditions, elevated [CO2] increased plant dry weight, leaf area, leaf relative water content and net photosynthesis compared with ambient [CO2], whilst the maximum potential quantum efficiency of photosystem II was not modified. In salt-stressed plants, elevated [CO2 ] increased leaf NO3(-) concentration and reduced Cl(-) concentration. Salinity stress induced ABA accumulation in the leaves but it was reduced in the roots at high [CO2], being correlated with the stomatal response. Under non-stressed conditions, IAA was dramatically reduced in the roots when high [CO2] was applied, which resulted in greater root DW and root respiration. Additionally, the observed high CK concentration in the roots (especially tZR) could prevent downregulation of photosynthesis at high [CO2], as the N level in the leaves was increased compared with the ambient [CO2], under salt-stress conditions. These results demonstrate that the hormonal balance was altered by the [CO2], which resulted in significant changes at the growth, gas exchange and nutritional levels.

Alleviation of drought stress by silicon supplementation in pistachio (Pistacia vera L.) plants

ABSTRACT The effect of silicon (Si) supplementation (0.35 g Na2SiO3 kg-1 soil, 2.73 mmol Si kg-1 soil) was studied in drought-stressed pistachio (Pistacia vera L. ‘Ahmadaghaii’) plants under field conditions. Silicon treatment significantly increased plant dry weight and relative water content under drought stress. The application of Si for drought-stressed plants improved the maximum quantum yield of PSII. A reduction in the net assimilation rate due to drought stress was alleviated by Si application, accompanied by an increase in stomatal conductance. Silicon treatment resulted in higher catalase and superoxide dismutase activities and lower lipid peroxidation in the leaves of drought-stressed plants. The results suggest that supplementation of water-deficient pistachio plants with Si alleviates the adverse effects of drought due to its enhancement of photochemical efficiency and photosynthetic gas exchange, as well as an activation of the antioxidant defence capacity in this species.