Root Protein Content Research Articles

Responses of root physiological characteristics and yield of sweet potato to humic acid urea fertilizer.

Humic acid (HA), not only promote the growth of crop roots, they can be combined with nitrogen (N) to increase fertilizer use efficiency and yield. However, the effects of HA urea fertilizer (HA-N) on root growth and yield of sweet potato has not been widely investigated. Xushu 28 was used as the experimental crop to investigate the effects of HA-N on root morphology, active oxygen metabolism and yield under field conditions. Results showed that nitrogen application alone was not beneficial for root growth and storage root formation during the early growth stage. HA-N significantly increased the dry weight of the root system, promoted differentiation from adventitious root to storage root, and increased the overall root activity, total root length, root diameter, root surface area, as well as root volume. HA-N thus increased the activity of superoxide dismutase (SOD), peroxidase (POD), and Catalase (CAT) as well as increasing the soluble protein content of roots and decreasing the malondialdehyde (MDA) content. HA-N significantly increased both the number of storage roots per plant increased by 14.01%, and the average fresh weight per storage root increased by 13.7%, while the yield was also obviously increased by 29.56%. In this study, HA-N increased yield through a synergistic increase of biological yield and harvest index.

Differential Phytotoxic Impact of Plant Mediated Silver Nanoparticles (AgNPs) and Silver Nitrate (AgNO3) on Brassica sp.

Continuous formation and utilization of nanoparticles (NPs) have resulted into significant discharge of nanosized particles into the environment. NPs find applications in numerous products and agriculture sector, and gaining importance in recent years. In the present study, silver nanoparticles (AgNPs) were biosynthesized from silver nitrate (AgNO3) by green synthesis approach using Aloe vera extract. Mustard (Brassica sp.) seedlings were grown hydroponically and toxicity of both AgNP and AgNO3 (as ionic Ag+) was assessed at various concentrations (1 and 3 mM) by analyzing shoot and root length, fresh mass, protein content, photosynthetic pigments and performance, cell viability, oxidative damage, DNA degradation and enzyme activities. The results revealed that both AgNPs and AgNO3 declined growth of Brassica seedlings due to enhanced accumulation of AgNPs and AgNO3 that subsequently caused severe inhibition in photosynthesis. Further, the results showed that both AgNPs and AgNO3 induced oxidative stress as indicated by histochemical staining of superoxide radical and hydrogen peroxide that was manifested in terms of DNA degradation and cell death. Activities of antioxidants, i.e., ascorbate peroxidase (APX) and catalase (CAT) were inhibited by AgNPs and AgNO3. Interestingly, damaging impact of AgNPs was lesser than AgNO3 on Brassica seedlings which was due to lesser accumulation of AgNPs and better activities of APX and CAT, which resulted in lesser oxidative stress, DNA degradation and cell death. The results of the present study showed differential impact of AgNPs and AgNO3 on Brassica seedlings, their mode of action, and reasons for their differential impact. The results of the present study could be implied in toxicological research for designing strategies to reduce adverse impact of AgNPs and AgNO3 on crop plants.

Levofloxacin is phytotoxic and modifies the protein profile of lupin seedlings

The toxicity of levofloxacin to yellow lupin plants was evaluated in this study. Recommended indexes of plant (roots and shoots) growth were determined and new indexes were proposed which better characterise the phytotoxicity of levofloxacin. These were, in particular, the activity of antioxidative enzymes, the content of free radicals, as well as the root protein content and the root protein profile. The results showed that levofloxacin considerably affected EC50, measured as the activity of catalase in roots, and leaves (1.05 and 0.069 mM, respectively). The activity of peroxidase in the roots and the dry weight of seedlings were the least sensitive parameters (EC50 was 1.8 and 1.76 mM, respectively). Units of toxicity clearly showed that the activity of catalase is a better measure of toxicity for low concentrations of the drug, and it is a better index of plant physiological state than the morphological parameters of seedlings. Moreover, levofloxacin changed the location of free radicals and the protein profile in plants. The changes in location of reactive oxygen species in roots were an important symptom of the drug toxicity to lupin seedlings. Our results have shown that the toxicity of levofloxacin was manifested mainly by changes in the protein profile. The content of the glyceraldehyde-3-phosphate dehydrogenase, 14-3-3-like protein A, expansin-B3-like precursor, fructose-bisphosphate aldolase, lipoxygenase, nucleotide-binding subunit of vacuolar ATPase and pyruvate dehydrogenase were found to decrease. On the other hand, plant exposure to levofloxacin resulted in an increase in the content of enolase, protein LlR18A, class III chitinase, ascorbate peroxidase, aspartate aminotransferase, alcohol dehydrogenase 1, leghemoglobin reductase-like 17 and heat shock cognate protein 80-like.

Influence of Drought Stress on Several Root Traits and their Correlation with Seed Protein and Oil Contents in Soybean

The important crop soybean [Glycine max (L.) Merr.] is cultivated worldwide and the US is its number one exporter. However, farmers face many challenges in cultivating soybeans, including drought and diseases that reduce yields drastically. The root system is very important for plants, including crops, because it receives water and minerals from the soil so that the plant/crop can photosynthesize, grow, and increase its yield. The objective of this study was to grow the ‘MD 96-5722’ by ‘Spencer’ recombinant inbred line (RIL) population (n=86) in the greenhouse under normal (Group I) and drought stress (Group II) conditions, and compare the root length (RL), root surface area (RSA), average root diameter (ARD), and average root volume (ARV) in the two groups of plants. WhinRhizo software was used to measure the root traits and SPSSTM was used to evaluate population performance under normal and drought conditions. JMPTM was used to compare the root traits under normal and drought conditions, and to analyze the correlation between root traits, protein and oil contents. The results showed that there is a huge variation in these traits among the parents ‘MD 96-5722’ and ‘Spencer’, and among their RILs. For Group I plants, the RL of parents and RILs ranged from 20.67 cm to 2,327.88 cm; the RSA ranged from 4.57 cm2 to 1,176.79 cm2; the ARD ranged from 0.38 mm to 4.04 mm; and the ARV ranged from 0.08 cm3 to 47.34 cm3. For Group II plants, the RL of parents and RILs ranged from 15.70 cm to 3,562.42 cm; the RSA ranged from 4.15 cm2 to 829.72 cm2; the ARD ranged from 0.24 mm to 5.74 mm; and the ARV ranged from 0.03 cm3 to 23.67 cm3. It is clear from the results that Group I plants have higher means of RL [572.58 cm vs. 537.33 cm], RSA [201.20 cm2 vs. 165.50 cm2], ARD [3.96 mm vs. 1.45 mm], and ARV [6.31 cm3 vs. 5.61 cm3] compared to Group II plants which demonstrates that drought-stressed plants have reduced overall plant growth and development. However, statistically, these differences were not significant; therefore, further studies with several replicates should be conducted both in the greenhouse and the field in order to determine the effects of drought stress on the ‘MD 96-5722’ by ‘Spencer’ RILs. Moreover, studies of quantitative trait loci (QTL) mapping of the root traits studied here are underway to genetically map QTL for these root traits in this soybean RIL population.

Seed priming with cobalamin (vitamin B12) provides significant protection against salinity stress in the common bean

Salinity is an important environmental factor that has a negative impact on plant growth. Availability of growth regulators plays a crucial role to enhance adverse effects of salinity. The effects of saline water irrigation and cyanocobalamin (vitamin B12) priming were evaluated on some growth parameters and biochemical attributes of common bean (Phaseolus vulgaris L.). The seeds were primed in various concentrations of vitamin B12 (0, 11, and 22µM). Ten seeds of each group were sown in plastic pots. All pots were placed into a growth chamber. Four weeks after sowing, salt stress treatment was initiated and nine of the pots were subjected to salinity stress by NaCl solution (75mM) daily. The remaining plants, as controls were irrigated with tap water. Effects were determined by leaf area, root and shoot length, root and shoot dry matter, antioxidant enzyme activity, protein content, chlorophyll and carotenoids, lipid peroxidation and proline accumulation. The results demonstrated that application of vitamin B12 provided significant protection against salinity stress compared with non treated plants. According to the outcomes, antioxidant enzyme activity, lipid peroxidation, carotenoid and proline accumulation increased due to NaCl stress while protein, chlorophyll and carotenoids decreased. Seed priming with vitamin B12 induced these stimulatory effects on all the measured parameters. Root protein and leaf carotenoid content were not affected by vitamin treatment under conditions of salinity stress. These results suggest that, vitamin B12 may have a critical role as an effective antioxidant and regulates osmotic balance thereby enhancing bean plant's resistance to salinity.

RNA-seq analysis reveals a key role of brassinolide-regulated pathways in NaCl-stressed cotton

Brassinolide (BL) alleviates salt injury in cotton seedlings; however, little is known about the molecular mechanisms of this response. In this study, digital gene expression analysis was performed to better understand the regulatory pathways of BL in NaCl-stressed cotton (Gossypium hirsutum L.). Compared with control plants (CK), a total of 1 162 and 7 659 differentially expressed genes (DEGs) were detected in the leaves and roots of NaCl-treated plants, respectively. Most of the DEGs in NaCl-treated plants, compared to CK, were regulated by BL. Moreover, expression patterns of DEGs in BL+NaCl treated plants were similar to those in CK plants; however, the responses of DEGs in the leaves and roots of NaCl-treated plants to BL differed. In the roots, BL-regulated DEGs were involved in protein biosynthesis, whereas in the leaves, BL promoted photosynthesis in NaCl-stressed cotton. BL treatment also significantly increased the overall biomass, chlorophyll a + b content in leaves, and the protein content in roots in NaCl-stressed cotton. The downregulation of stress-responsive genes in BL+NaCl-stressed leaves was also found. These results suggest that BL can alleviate NaCl injury in cotton plants.

Biochemical and plant nutrient alterations induced by Meloidogyne javanica and Fusarium oxysporum f.Sp.radicis lycopersici co-infection on tomato cultivars with differing level of resistance to M. javanica

The experiment was conducted to assess plant nutrient levels and biochemical changes in tomato roots Solanum lycopersicum Mill. cultivars in response to Fusarium oxysporum f.sp. radicis lycopersici (FORL) and/or Meloidogyne javanica (RKN) infection. The enzyme activity, total sugar concentration, total phenol and protein content in tomato roots of resistant (Firenze), intermediate resistant (Colibri) and susceptible cultivar (Riogrande) at seven days post infection by FORL and RKN were measured. Tomato plants (45 days post-inoculation) were quantified by atomic spectrometry for Cu, Zn, Fe, Mn, Mg, K and Ca contents in roots. At seven days post infection, defense responses involving enzymes were observed in tomato roots. Peroxidase (POX), catalase (CAT), polyphenoloxidase (PPO) and superoxide dismutase (SOD) enzymes activities were enhanced after pathogen infection and this increase was greater with synergetic infection by RKN and FORL and more in the resistant cultivar when compared to the susceptible one. Total protein content, sugar concentration and total phenol content variations were correlated to pathogen co-infection and not to the resistance level of the tomato. It was concluded that synergetic infection by FORL and RKN induced plant defense response especially in resistant cultivars. Those responses diverged with single or dual infection by pathogens and with resistance level on host plant. The nematode-fungi disease complex had great impact on unbalancing nutrients contents in roots by reducing significantly (P < 0.05) the contents of Cu, Zn, Fe, Mn, Mg and K. However, The Ca content was increased in roots. All tomato cultivars responded similarly on changing nutrient content independently with resistance level.

Selenium Biofortification in Radish Enhances Nutritional Quality via Accumulation of Methyl-Selenocysteine and Promotion of Transcripts and Metabolites Related to Glucosinolates, Phenolics, and Amino Acids.

Two selenium (Se) fertilization methods were tested for their effects on levels of anticarcinogenic selenocompounds in radish (Raphanus sativus), as well as other nutraceuticals. First, radish was grown on soil and foliar selenate applied 7 days before harvest at 0, 5, 10, and 20 mg Se per plant. Selenium levels were up to 1200 mg Se/kg DW in leaves and 120 mg Se/kg DW in roots. The thiols cysteine and glutathione were present at 2–3-fold higher levels in roots of Se treated plants, and total glucosinolate levels were 35% higher, due to increases in glucoraphanin. The only seleno-aminoacid detected in Se treated plants was Se-methyl-SeCys (100 mg/kg FW in leaves, 33 mg/kg FW in roots). The levels of phenolic aminoacids increased with selenate treatment, as did root total nitrogen and protein content, while the level of several polyphenols decreased. Second, radish was grown in hydroponics and supplied with 0, 5, 10, 20, or 40 μM selenate for 1 week. Selenate treatment led to a 20–30% increase in biomass. Selenium concentration was 242 mg Se/kg DW in leaves and 85 mg Se/kg DW in roots. Cysteine levels decreased with Se in leaves but increased in roots; glutatione levels decreased in both. Total glucosinolate levels in leaves decreased with Se treatment due to repression of genes involved in glucosinolates metabolism. Se-methyl-SeCys concentration ranged from 7–15 mg/kg FW. Aminoacid concentration increased with Se treatment in leaves but decreased in roots. Roots of Se treated plants contained elevated transcript levels of sulfate transporters (Sultr) and ATP sulfurylase, a key enzyme of S/Se assimilation. No effects on polyphenols were observed. In conclusion, Se biofortification of radish roots may be achieved via foliar spray or hydroponic supply. One to ten radishes could fulfill the daily human requirement (70 μg) after a single foliar spray of 5 mg selenate per plant or 1 week of 5–10 μM selenate supply in hydroponics. The radishes metabolized selenate to the anticarcinogenic compound Se-methyl-selenocysteine. Selenate treatment enhanced levels of other nutraceuticals in radish roots, including glucoraphanin. Therefore, Se biofortification can produce plants with superior health benefits.

Genetic Variability for Yield and Nutritional Quality in Yam Bean (Pachyrhizus sp.)

The amount of genotypic and phenotypic variability that exists in a species is important for selection and initiating breeding programs. Yam bean is grown locally in tropical countries of the Americas and Asia for their tasty storage roots, which usually have low dry matter content. The crop was recently introduced in Uganda and other East and Central African countries to supplement iron (Fe) and protein content in diets. This study aimed to estimate genetic variability for root yield and quality traits among 26 yam bean accessions in Uganda. A randomized complete block design was used with two replications across two ecogeographical locations and two seasons during 2012 and 2013. Near-infrared reflectance spectroscopy (NIRS) was used to determine quality of storage root samples. Significant differences among genotypes were observed for all traits except root protein, zinc (Zn), and phosphorus contents. Genotypic variance components () were significant for storage root fresh yield (SRFY), storage root dry matter (SRDM), storage root dry yield (SRDY), vine yield (VNY), fresh biomass yield (FBY), and storage root starch (STA) and Fe contents. For traits with significant the broad sense heritability estimates ranged from 58.4% for SRDY to 83.6% for FBY; and phenotypic coefficients of variation were high for SRFY (66%), SRDY (53.3%), VNY (60.5%), and FBY (59%), but low to medium for SRDM (22.6%), STA (15.1%), and Fe (21.3%). Similarly, the genotypic coefficients of variation were high for SRFY (56.7%), SRDY (53.3%), VNY (55%), and FBY (53.9%); and low for SRDM (20%), STA (12.4%), and Fe (17.8%). There were strong positive correlations between SRFY and both SRDY (r = 0.926) and FBY (r = 0.962), but low-to-moderate correlations among quality traits. It should be possible to breed for high dry matter yam beans by using low dry matter accessions due to the observed genetic variation ( = 9.3%2), which is important if the high dry matter Pachyrhizus tuberosus accessions (known as chuin) from Peru cannot be accessed. This study indicated substantial genetic variation for yield and quality traits in yam bean, demonstrating potential for adaptability to growing conditions and consumer needs in East and Central Africa and for genetic improvement through selection.

The roles of protein and lipid in the accumulation and distribution of perfluorooctane sulfonate (PFOS) and perfluorooctanoate (PFOA) in plants grown in biosolids-amended soils

The roles of protein and lipid in the accumulation and distribution of perfluorooctane sulfonate (PFOS) and perfluorooctanoate (PFOA) in seven species of plants from biosolids-amended soils were investigated. The PFOS and PFOA root concentration factors (Croot/Csoil) ranged from 1.37 to 4.68 and 1.69 to 10.3 (ng/groot)/(ng/gsoil), respectively, while the translocation factors (Cshoot/Croot) ranged from 0.055 to 0.16 and 0.093 to 1.8 (ng/gshoot)/(ng/groot), respectively. The PFOS and PFOA accumulations in roots correlated positively with root protein contents (P < 0.05), while negatively with root lipid contents (P < 0.05). These suggested the promotion effects of protein and inhibition effects of lipid on root uptake. The translocation factors correlated positively with the ratios between protein contents in shoots to those in roots (P < 0.05), showing the importance of protein on PFOS and PFOA translocation. This study is the first to reveal the different roles of protein and lipid in the accumulation and distribution of PFOS and PFOA in plants.

Salicylic acid induced cysteine protease activity during programmed cell death in tomato plants

The hypersensitive response (HR), a type of programmed cell death (PCD) during biotic stress is mediated by salicylic acid (SA). The aim of this work was to reveal the role of proteolysis and cysteine proteases in the execution of PCD in response of SA. Tomato plants were treated with sublethal (0.1 mM) and lethal (1 mM) SA concentrations through the root system. Treatment with 1 mM SA increased the electrolyte leakage and proteolytic activity and reduced the total protein content of roots after 6 h, while the proteolytic activity did not change in the leaves and in plants exposed to 0.1 mM SA. The expression of the papain-type cysteine protease SlCYP1, the vacuolar processing enzyme SlVPE1 and the tomato metacaspase SlMCA1 was induced within the first three hours in the leaves and after 0.5 h in the roots in the presence of 1 mM SA but the transcript levels did not increase significantly at sublethal SA. The Bax inhibitor-1 (SlBI-1), an antiapoptotic gene was over-expressed in the roots after SA treatments and it proved to be transient in the presence of sublethal SA. Protease inhibitors, SlPI2 and SlLTC were upregulated in the roots by sublethal SA but their expression remained low at 1 mM SA concentration. It is concluded that in contrast to leaves the SA-induced PCD is associated with increased proteolytic activity in the root tissues resulting from a fast up-regulation of specific cysteine proteases and down-regulation of protease inhibitors.

Increased drought tolerance in maize plants induced by H2O2 is closely related to an enhanced enzymatic antioxidant system and higher soluble protein and organic solutes contents

Drought stress is one of the most important agricultural problems limiting development and growth in plants. Therefore, mechanisms to alleviate drought stress have been one of the major limiting factors in production. H2O2 pretreatment has emerged as a method to induce stress acclimation in plants. In this study, the effects of H2O2 leaf pretreatment on plant growth, antioxidative enzymes, soluble protein, and organic solute content in maize plants under conditions of drought stress were analyzed. Results demonstrated that drought stress reduced shoot and root mass compared with the control, and H2O2 leaf spraying significantly improved the growth of drought-stressed plants. In general, in drought-stressed plants, CAT, APX, GPX, and SOD activities in roots and leaves were increased by H2O2 leaf spraying relative to water spraying. GPX was the main H2O2-scavenging enzyme in leaves and roots, and CAT activity was not detected in the leaves of maize plants. Increased organic solute contents (proteins, carbohydrates, soluble proline, and amino acids) were found in the leaves and mainly in the roots of H2O2-stressed plants relative to water-stressed plants. In conclusion, it was found that H2O2 leaf spraying pretreatment reduced the deleterious effects of drought stress on maize plant growth. This treatment proved to be a beneficial health strategy in plants. This effect could be attributed to the ability of H2O2 to induce antioxidant defense system activity, particularly GPX, and to increase organic solute (protein, carbohydrate, proline, and free amino acid) content in roots and leaves.

Foliar application of betaine alleviates cadmium toxicity in maize seedlings

Greenhouse hydroponic experiments were performed to investigate the effect of the foliar application of betaine on the growth and physiological traits of maize seedlings in a setting of cadmium (Cd) toxicity. The foliar application of 500 μM betaine for maize exposed to culture medium containing 50 μM Cd significantly alleviated Cd-induced growth inhibition and dramatically decreased malondialdehyde (MDA) accumulation and shoot Cd concentration. Exogenous betaine significantly elevated the Cd-depressed soil plant analysis development (SPAD) value and improved photosynthetic performance (i.e., net photosynthetic rate, intercellular CO2 concentration, transpiration rate, and water use efficiency). External betaine significantly increased betaine content, shoot soluble protein content and catalase (CAT) activity in shoots and roots, but did not affect the ascorbate peroxidase (APX), superoxide dismutase (SOD) and guaiacol peroxidase (POD) activities; furthermore, betaine enhanced the Cd-induced decrease in root Zn, Cu, and Fe concentrations and dramatically decreased Cd-induced increases in Na+K+-, Ca2+Mg2+- and total ATPase activities, which recovered to levels similar to those of the control. Furthermore, addition of betaine ameliorated the Cd-induced damage to the leaf/root ultrastructure. This research may elucidate how betaine improves the stress resistance of crops.

Amaranth Plant: Protects Climate, Health and Development by Controlling Root-Knot Disease

Plant diseases, caused by pathogens, significantly reduce food production particularly in the developing world. Syntheticand chemical- pesticides are the most effective means of control, but they are expensive and not environment friendly. Population growth and rapid urbanization are putting considerable pressure on water available for irrigation. The “evils” of synthetic- and chemical- pesticides has been a major concern to environmentalists. To move forward, it will require new and more efficient solutions, technologies and products. Our best endeavor is to focus on the edible Amaranth which may have important economic implications for agriculture in future. In a well-protected garden of Kanchannagar DN Das High School (HS), Government of West Bengal, naturally-infested with Meloidogyne incognita, Kofoid and White, Chitwood, amaranth (Amaranthus viridis L.) cv. CO-1 was intercropped with okra (Abelmoschus esculentus L. Moench) cv. Ankur-40 to determine the effects on nematode populations. The nematode population varied from 2573- 2639 per 200 g of soil. Amaranth was planted in between every two okra plants. All the plants were harvested at 70 days after plantation. Of the two plant species, amaranth received maximum infection in terms of root gall number, nematode population in root, root protein content and plant growth parameters. Though both the amaranth and okra plants were susceptible to root-knot nematodes. Amaranth was more susceptible than okra in terms of root-gall number nematode population in root and root protein content. Okra has also the lowest root-gall number and nematode population in root. While M. incognita population increased significantly both in soil as well as in roots in 70 days in the monoculture. But amaranth showed the highest intensity of nematode infection. These results suggest that root-knot disease easily and effectively controlled by the use of amaranth plants as “trap crop” for root-knot nematodes intercropped with okra plants in the naturally root-knot infested field. As intercrop amaranth could be harvested at frequent intervals to keep the nematode population to a minimum level. This way amaranth could serve as highly effective Climate Friendly Catch Crop protecting other crops from invading larvae. The farmers would be benefited double; by controlling root-knot nematodes in the naturally infected agricultural field, and by buying and selling the edible amaranth plant regularly from the intercropped agricultural field. Intercropped amaranth also improves the plant growth effectively which directly increase photosynthesis rate and significantly reduce CO2 in the environment and it would not only be easier way, easily available, cheap but also conserve our biodiversity which will contribute towards “Sustainable Climate, Health and Development by controlling root-knot diseases which is sometime devastating to all kinds of natural and artificial vegetation.”

Stimulation with a 130-mT magnetic field improves growth and biochemical parameters in lupin (Lupinus angustifolius L.)

The influence of magnetic field stimulation (MFS) on plants is a subject of intense research. The influence of MFS on plants varies depending on its intensity, time of exposure, and form of application. Weak MFS has beneficial effects on physiological and biochemical processes in plant tissues. Lupins (Lupinus spp.) are economically and agriculturally important plants used mainly in livestock feeding or in human consumption. The effects of a stationary magnetic field (130 mT) on the mitotic activity and selected biochemical parameters of lupin (Lupinus angustifolius L.) were evaluated. Nonexposed plants were used as the control. It was noted that the stimulation of plants with a 130-mT magnetic field favored the aboveground parts of the plants, which was manifested by an increase in the average length and fresh weight of shoots and an increase in the photosynthetic pigment content. However, guaiacol peroxidase activity decreased in shoots after their exposure to 130-mT MFS. The development of roots was at the control level. Moreover, an increase in the total protein content in both shoots and roots was observed after the MFS.

Phytotoxicity of dimethyl sulfoxide (DMSO) to rice seedlings

The physiological responses of dimethyl sulfoxide (DMSO) exposure were investigated in rice (Oryza sativa L. cv. XZX 45) seedlings. The seedlings were hydroponically exposed to different concentrations of DMSO for 72 h. Results showed that a linear decrease in relative growth rate and water use efficiency was observed with rice seedlings with increasing DMSO concentrations. The estimation of cell death measured by Evans blue uptake also indicated DMSO-induced damage in root tissues. Negligible decrease in chlorophylls was noted, while significant reduction in carotenoids content was only observed at 13.54 mM DMSO. Although DMSO did not have any significant effect on protein content in roots, the protein content in shoots was significantly decreased in a dose-dependent manner. Proline content in both plant tissues was positively affected by DMSO exposure, responding an inverted U-shaped curve with DMSO concentrations. Results also showed that DMSO-induced accumulation of hydrogen peroxide (H2O2) was evident in roots rather than shoots. DMSO did not result in any significant changes in superoxide dismutase and peroxidase activities as well as malondialdehyde content. Catalase (CAT) activity in both roots and shoots was quite sensitive to changes in DMSO treatments than other enzymes, suggesting that CAT may play central role in the detoxification of H2O2 in rice seedlings under DMSO exposure. Results suggest that growth inhibition and cell death of rice seedlings caused by DMSO exposure were largely related to the accumulation of H2O2 in plant tissues.

Root-applied brassinolide can alleviate the NaCl injuries on cotton

Brassinolide (BL) is a plant growth regulator. This study analyzes the effects of BL on cotton growth, Na+ accumulation, proline content, MDA content, antioxidant enzyme activities, and differentially expressed genes (DEGs) of cotton roots under NaCl stress. We grew two cotton cultivars, Sumian 12 (salt sensitive) and Sumian 22 (salt tolerant), in continuously aerated Hoagland’s nutrient solution supplemented with 200 mM NaCl. NaCl stress increased the Na+, proline, and MDA content and decreased root activity and protein content in the roots of Sumian 12 and 22, and the change rang of Sumian 12 was higher than that of Sumian 22. The application of BL counteracted the NaCl stress-induced growth inhibition in the two tested cotton cultivars. It reduced the accumulation of Na+, enhanced proline content, and resulted in an overall change in the activities of antioxidant enzymes causing a decrease in the MDA content of NaCl-stressed roots, and the influence of BL on salt-stressed Sumian 12 plants was more pronounced than that on Sumian 22. The digital gene expression analysis in Sumian 12 indicated that BL application significantly influenced the gene expression in NaCl-stressed roots. The majority of 7659 (3661 up-regulated/3998 down-regulated) DEGs of NaCl/CK in roots of Sumian 12 were regulated by BL, and the gene expression pattern as a result of the root-applied BL on NaCl-stressed cotton treatment (BL + NaCl) was similar to the control. Our results indicate that the root-applied brassinolide alleviates NaCl stress on cotton through improving root activity, physiology, and gene expression.

Effect of di-n-butyl phthalate on root physiology and rhizosphere microbial community of cucumber seedlings

The authors investigated the effects of di-n-butyl phthalate (DBP) on root physiology and rhizosphere microbial communities of cucumber seedlings (sativus L. cv Jinyan No. 4). Root protein content and root activity were observed to decrease. From the ultrastructural micrographs, visible impact on the mitochondria, endoplasmic reticulum and vacuole were detected. Moreover, the number of starch grains increased, and some were adhered to other cell components which might be the most direct evidence of DBP causing cellular damage. Results of PCR-DGGE (denaturing gradient gel electrophoresis) indicated that DBP significantly changed the abundance, structure and composition of rhizosphere bacteria when the concentration was higher than 50mgL−1. The relative abundances of Firmicutes increased while that of Bacteroidetes decreased. Bacillus was detected as the dominant bacteria in DBP contaminated cucumber rhizospheric soil. The amount of Actinobacteridae and Pseudomonas decreased until it disappeared in the rhizosphere soil when exposed to DBP concentrations higher than 50mgL−1.

English

Manihot esculenta spp flabellifolia is a potential progenitor for cassava root protein content and yield improvement. Storage roots of cassava landraces are low in protein content due to the fact that past breeding objectives concentrated mainly on yield and resistance to diseases. The improvement of cassava through its wild progenitor is of importance for the full utilization of the potential of the wild progenitor. An interspecific F1 was crossed to a cultivated variety (MTAI - 8) to generate a backcross population. Root protein, yield and other quality traits were evaluated. High root protein content of 9.61%; fresh root yield of 60.00 ton ha-1; dry root yield of 34.75 ton ha-1; and dry matter content of 59.45% was found in this population. High broad-sense heritability was obtained for all the traits evaluated which is a good indicator that genetic improvement can be achieved in this population. This first backcross population had protein values higher than the earlier documented values in the landraces. Key word: Cassava, Manihot esculenta ssp flabellifolia, interspecific, protein and yield.

Various Applications of Seaweed Improves Growth and Biochemical Constituents of Zea Mays L. and Helianthus Annuus L.

In this study, the effect of seaweed on the growth of Zea mays L. and Helianthus annuus L. was investigated. Seeds of the plants have been soaked for 6 hours in 0.5% Gracilaria corticata and 1.0% Enteromorpha flexuosa aqueous extract. The presoaked seeds were sown both in soil irrigated monthly with aqueous extract and in soil mixed with powdered seaweeds. Growth parameters of plants were studied after 60 days of growth. The results revealed that both applications of G. corticata and E. flexuosa enhance shoot length, root length, shoot and root dry weights, photosynthetic pigments, carbohydrate and protein contents, and nutrient uptake. The maximum growth was observed with irrigation by E. flexuosa extract. The element constituent [nitrogen (N), phosphorus (P), potassium (K+), calcium (Ca2+), magnesium (Mg2+), iron (Fe3+), manganese (Mn2+), and zinc (Zn2+)] and phytohormones [Indole-3-acetic acid (IAA), gibberellins, and cytokinins] of E. flexuosa extract and powder was higher that of G. corticata. Of the two seaweeds tested, E. flexuosa exhibited better responses.