Plant Fresh Mass Research Articles

Effects of organic fertilizers on growth and biochemical characteristics of Fenugreek

Fenugreek (Trigonella foenum-graecum L.) is an annual herb used as organic (green) manure and has medicinal applications. Organic fertilizers are used in sustainable agriculture of vegetables. Sources of organic manure and their effects on growth and yield characteristics of plants need to be determined. Effects of vermicompost and vermiwash were determined on qualitative and quantitative factors of chemical content, development and yield of fenugreek (Trigonella foenum-gaecum L.) from May to July 2012 at Agriculture College of University Guilan. A completely randomized block design with 3 replications was used. Treatments included 7 t/ha of cow manure, vermicompost, vermiwash (obtained from 7 t/ha vermicompost); 7 t/ha of leachate vermicompost + vermiwash and a control (no fertilization). Use of organic fertilizers beneficially affected plant height, pod length, pod fresh and dry mass, 1000-seed mass, plant fresh and dry mass, internode length and percents of leaves protein and nitrogen. Use of organic fertilizers may increase yield and yield components of fenugreek and its yield efficiency.

Effects of Glomus intraradices on the drought resistance and growth of corn plant (Zea mays L.)

A pot experiment was carried out at the greenhouse of Faculty of Agriculture (Saba bacha), Alexandria University. The experiment was conducted to investigate the role of Glomus intraradices fungi in the effects on the growth and water requirement of pot-grown corn (Zea mays L.). Four water regimes (20%, 30%, 40% and 50% of the available soil water content) were conducted. The Arbuscular Mycorrhizal Fungi AMF inoculation could significantly increase plant growth (including plant height, leaf area, and fresh and dry mass), enhance relative leaf water content, transpiration rates and stomatal conductance, and improve plant drought tolerance. The water consumption of the mycorrhizal plants producing 1 g of dry matter was 20%–35% of water content conditions. These findings indicate that the mycorrhizae enhanced the water utilization efficiency.

Effect of foliar application of brassinolide on photosynthesis and chlorophyll fluorescence traits of Leymus chinensis under varying levels of shade

The present study was conducted to determine the effect of exogenous application of brassinolide (BR) on Leymus chinensis grown under shade, i.e., control (100% natural light), mild shade (70% natural light), and moderate shade (50% natural light). Shade substantially enhanced the plant growth, synthesis of photosynthetic pigments, photosynthetic efficiency, and chlorophyll (Chl) fluorescence attributes of L. chinensis as compared with control. The order of increase was mild shade > moderate shade > natural light except Chl content, where the order of increase was moderate shade > mild shade > natural light. Likewise, application of BR resulted in further exacerbation of plant height, plant fresh and dry mass, but less in case of Chl and carotenoids contents, gas-exchange characteristics, and Chl fluorescence attributes. The results conclude that shade significantly enhanced plant growth through alterations in physiological attributes of L. chinensis, while, application of BR may not further improve the plant growth under shade.

Does exogenous application of ascorbic acid modulate growth, photosynthetic pigments and oxidative defense in okra (Abelmoschus esculentus (L.) Moench) under lead stress?

Seed priming increases tolerance of plants against various environmental stresses. Although ample literature is available that depicts the beneficial effects of priming under different environmental stresses, the information on induction of tolerance to Pb stress through seed priming with ascorbic acid (AsA) is limited. Therefore, this study was performed to examine the effect of seed priming with AsA (50 and 100 mg L−1), hydropriming and without priming (control) on physiochemical processes of okra cultivars (Subz-Pari and Arka Anamika) under Pb stress (0, 100 mg L−1). Pb stress caused a considerable decline in plant growth and photosynthetic pigments. Contrarily, Pb stress exhibited rise in the contents of total amino acids, free proline, total soluble proteins and AsA. The POD, CAT, and SOD activities were recorded highest at 100 mg L−1 of Pb. Moreover, Pb stress markedly increased H2O2 and MDA levels that triggered oxidative stress. However, plants raised from seed primed with AsA and water exhibited better growth and had higher chlorophylls, free proline, total proteins, total amino acids, AsA and activities of enzymatic antioxidants. Priming with AsA (50 mg L−1) induced better tolerance to Pb stress in okra plants. Plants of cv. Arka Anamika exhibited greater tolerance to Pb than that of cv. Subz-Pari as was evident from higher plant fresh and dry masses.

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ability to associate symbiotically with rhizobia. The objective of this study was to isolate, authenticate and select effective rhizobia obtained from native serradella (Ornithopus micranthus) to reduce the need for mineral fertilizer. Nodules, roots of serradella and rhizosphere soil samples were collected in seven municipalities from Rio Grande do Sul and Santa Catarina states. Bacterial colonies were isolated and identified based on morphological characteristics. The authentification and initial selection of rhizobia were conducted in vitro. The most promising strains from the in vitro study were evaluated in a greenhouse experiment for 60 days. Among the 148 bacterial cultures characterized, 113 induced the formation of nodules in serradella while 32 isolate effectively increased fresh mass of plants under in vitro conditions. The strains UFRGS Om57, UFRGS Om59 and UFRGS Om148 formed nodules with greater dry mass and produced high dry mass of plants (shoots and roots) which allowed greater accumulation of N in the shoots. Key words: Plant growth promoting rhizobacteria (PGPR); biological fixation of nitrogen; Ornithopus micrantus; pasture.

Physiological responses and tolerance to drought stress of different watermelon genotypes.

With the continuous drought stress treatment to 12 pot-grown watermelon genotypes originated from different regions, the influence of drought stress on plant height, root length, fresh mass and dry mass was studied, and the physiological responses of these genotypes to drought stress were compared. Drought resistance of these watermelon genotypes was preliminarily determined according to the drought injury, and then confirmed by membership function evaluation method. We found that the watermelon genotypes exhibited great difference in drought tolerance based on the occurrence of drought injury and the degree of injury severity. Drought stress reduced plant height, shoot- and root- fresh mass as well as shoot- and root- dry mass, while increased the root/shoot ratio for most genotypes; but for root length and root dry mass, it had both positive and negative effects depending on the tested genotype. Compared with the control, all drought-treated watermelon genotypes exhibited a decline in leaf relative water content and chlorophyll content, as well as increases in MDA, H2O2, O2-· and proline contents. Different watermelon genotypes displayed diversity in soluble protein content and antioxidant enzyme activity. Our results showed that three wild watermelon genotypes including M20, Y-2, and KY-3 were drought tolerant while Y34, 04-1-2 and Golden Girl were drought sensitive, and the rest genotypes were among the medium.

Crescimento e desenvolvimento de Hemerocallis fulva submetidos a doses de nitrogênio e fósforo

The objective was to evaluate the effect of different doses of nitrogen and phosphorus on growth and development of Hemerocallis fulva variety Flore Full, herbaceous perennial widely used in landscaping. The experimental design was randomized blocks with 25 treatments, arranged in a factorial 5 x 5 (0; 75; 150; 225 and 300 kg ha-1 N and 0, 100, 200, 300 and 400 kg ha-1 P), with 4 replicates. The phosphorus fertilization was carried out 15 days after planting (DAP) and nitrogen was applied in coverage divided in three equal applications at 15, 120 and 240 DAP. There were evaluated the plant height, number of tillers per plant, soil coverage area, the fresh mass of plant, root system and shoot; and the dry mass of plant, root system and aerial part, and calculated the ratio of root dry mass and plant dry mass. It was also obtained the nutrient content of the leaf tissue and root system. The highest tillering was gained with the use of 150 kg ha-1 N combined with 400 kg ha-1 of P. Intermediate doses of N (75-170 kg ha-1 of N) showed higher production of plant fresh and dry mass and root dry mass. Doses of N and P influenced the N and P content in plant tissues of roots and leaves of Hemerocallis. Plants fertilized with 300 kg ha-1 of N and 273 kg ha -1 of P lead to the highest levels of N in the leaves and doses of 80 kg ha-1 of N and 68 kg ha-1 P, the highest content of P in the leaves of H. fulva. Already, in the roots, the highest N content was obtained with application of 300 kg ha-1 N in the presence of P and doses of 225 kg N ha-1 combined with 300 ha-1 P provided the highest P content in the roots.

Salt stress response in the halophyte Limoniastrum guyonianum Boiss

Limoniastrum guyonianum is an evergreen perennial halophyte. Its response to severe salinity was investigated by exposing ninety-day-old plantlets to a 0–1000mM NaCl range for 3 months. Growth, water status, electrolyte leakage (EL), malondialdehyde (MDA) content, salt excretion, leaf pigment content, photosynthetic parameters, chloroplast ultrastructure, and contents of Na+, Cl−, K+, Ca2+, Mg2+, proline and polyphenols were determined. Results of these studies indicate that L. guyonianum is a facultative halophyte and can survive at 1000mM NaCl. Plants treated with 300mM NaCl had a 25% increase in whole plant fresh mass that is attributed to increased photosynthetic activity and adequate water uptake. Sodium and chloride accumulation increased with salinity and was associated with significant reductions in leaf K+, Ca2+ and Mg2+ concentrations due to excretion out of leaves. Consequently, photosynthetic machinery was highly preserved against toxic ions. Polyphenol accumulation increased with salt treatments while lipid peroxidation decreased with salinity levels at 200–1000mM NaCl. Proline accumulation increased with salt treatments up to and including 400mM NaCl. The increase in intrinsic water use efficiency at medium salt levels indicates that L. guyonianum is efficient at using the low available water under salt stress. These physiological and biochemical responses to salinity and the salt excretion process allowed L. guyonianum to tolerate severe salinity.

Changes in plant growth and photosynthetic performance of Zizania latifolia exposed to different phosphorus concentrations under hydroponic condition

The effects of phosphate concentration on plant growth and photosynthetic performance were examined in leaves of Zizania latifolia. Plants were grown for four weeks in a solution containing 0, 0.16, 0.64, and 2.56 mM orthophosphate. The results showed that the highest net photosynthetic rate (P N) was achieved at 0.64 mM orthophosphate, which corresponded to the maximum content of organic phosphorus in leaves. Low phosphorus (low-P) content in the culture solution inhibited plant growth, affecting plant height, leaf length, leaf number, tiller number, and fresh mass of leaf, sheath, culm, root, and total plant. In addition, we observed that low-P (0.16 mM) did not hinder the growth of roots but increased the root:shoot ratio, and significantly decreased the chlorophyll content, P N, stomatal conductance, and transpiration rate, but increased the intercellular CO2 concentration. Additionally, low-P significantly decreased the maximum carboxylation rate of Rubisco, the maximum rate of ribulose-1,5-bisphosphate regeneration, the effective quantum yield of PSII photochemistry, photochemical quenching coefficient, and electron transport rate, but increased the nonphotochemical quenching. However, the maximal quantum yield of PSII photochemistry was not significantly affected by low-P. High phosphorus (2.56 mM) caused only a slight decrease in gas-exchange parameters. Therefore, the decrease in growth of P-deficient Z. latifolia plants could be attributed to the lowered photosynthetic rate.

Effect of Plant Growth Regulators on Growth, Yield, and Quality of Sweet Pepper Plants Grown Hydroponically

A 2-year study (2012–13 and 2013–14) was conducted to evaluate the effect of plant growth regulator’s (PGRs) on plant growth, yield, and quality of hydroponically grown sweet peppers. In 2012–13, sweet pepper plants were subjected to two levels of gibberellic acid (GA3) (10 and 15 mg·L−1), two levels of naphthalene acetic acid (NAA) (15 and 30 mg·L−1), and four combinations of NAA and GA3 (10 mg·L−1 GA3 + 15 mg·L−1 NAA, 10 mg·L−1 GA3 + 30 mg·L−1 NAA, 15 mg·L−1 GA3 + 15 mg·L−1 NAA, and 15 mg·L−1 GA3 + 30 mg·L−1 NAA) applied to plants at flower initiation in a non-temperature-controlled tunnel. This PGR application was repeated 60 days after transplanting (DAT). In 2013–14, in addition to previously mentioned treatments, two levels of 4-chlorophenoxyacetic acid (4-CPA), at 30 and 45 mg·L−1, were applied at flower initiation followed by three additional applications of the latter treatments at 20-day intervals in a temperature-controlled tunnel. Marketable and total yield were markedly reduced by application of 4-CPA at 30 and 45 mg·L−1. Plant height was increased by application of GA3, and GA3 in combination with NAA, compared with application of 4-CPA, 30 mg·L−1 NAA, and the control. Results also showed that application of GA3 at 10 and 15 mg·L−1 or in combination with NAA increased plant fresh and dry mass as well; however, this had no beneficial effect on the yield of sweet pepper fruit. The application methods and concentrations of various PGRs needs further investigation under different growing conditions on sweet pepper cultivars.

Characterisation of antagonistic Bacillus and Pseudomonas strains for biocontrol potential and suppression of damping‐off and root rot diseases

AbstractNovel strains of rhizobacteria, Pseudomonas fluorescens Pf 9A‐14, Pseudomonas sp. Psp. 8D‐45 and Bacillus subtilis Bs 8B‐1, showed broad‐spectrum antagonistic activity and provided suppression of Pythium damping‐off and root rot of cucumber. Their biocontrol potential was further investigated for suppression of additional seedling diseases of cucumber (Phytophthora capsici) and radish (Rhizoctonia solani). Bacterial strains were also characterised for production of antibiotics, metabolites, volatiles, phytohormones and lytic enzymes. Seed and pre‐plant applications of all three antagonistic bacteria as cell suspension and talc or irradiated peat formulations to the infested potting mix provided overall high level of suppression of Phytophthora damping‐off and root rot of cucumber (66–85% healthy seedlings) and relatively low level of suppression of Rhizoctonia damping‐off of radish (18–38% healthy seedlings). Bacterial treatments also resulted in higher plant fresh masses. Seed coating with irradiated peat formulation of a mixture of three bacteria resulted in superior control of Phytophthora damping‐off and root rot of cucumber and much higher plant fresh masses. The presence of genes for biosynthesis of phenazine‐1‐carboxylic acid, 2,4‐diacetylphloroglucinol, pyrrolnitrin and pyoluteorin was confirmed in Pseudomonas strains, and that of fengycin, bacillomycin, bacilysin, surfactin and iturin A in B. subtilis Bs 8B‐1. All three strains produced HCN, salicylic acid, indole‐3‐acetic acid, protease and β‐1,3‐glucanase. Both Pseudomonas strains produced siderophores and only P. fluorescens Pf 9A‐14 showed phosphate solubilisation and chitinase activity. All three strains inhibited pathogen growth by producing volatiles, and gas chromatography–mass spectrometry analysis revealed eight compounds in Pf 9A‐14, 10 in Bs 8B‐1 and 4 in Psp 8D‐45, some with known antifungal activity. The antagonistic and plant‐growth promotion activities of these strains might be due to production of antibiotics, metabolites, lytic enzymes or phytohormones.

Physiological responses of two poplar species to high boron stress

Aims In recent years, international studies have found that poplar species could accumulate high boron with hy- pertolerance ability. Our objective was to investigate the effect of growth and physiological indicators of Populus russkii and P. bolleca under different boron concentrations, and determine the interspecific difference on boron tolerance, to help explaining and providing certain theoretical basis of phytoremediation technology for boron pollution treatment. Methods Poplar cuttings were grown in potting soil and added boron after three months. Physiological proper- ties tested included plant height, fresh biomass, chlorophyll fluorescence parameters, chlorophyll content, activi- ties of catalase (CAT) and guaiacol peroxidase (Gu-POD), soluble protein (SP) content and soluble carbohydrate (SC) content. Important findings Boron stress seriously inhibited the growth and affected the chlorophyll fluorescence pa- rameters of the two poplar species. Populus russkii was more sensitive than P. bolleca to boron stress, and P. bol- leca could stand higher boron level than P. russkii. The boron damage threshold (10%) of P. russkii and P. bolleca were 19 and 35 mg·kg -1 , respectively. The plant height, fresh mass and chlorophyll decreased linearly with the increase of soil boron concentrations. For antioxidant parameters analysis, the activities of CAT and Gu-POD in- creased at first, and then decreased with increasing concentration of applied boron. Populus bolleca kept higher chlorophyll a/b and non-photochemical quenching than P. russkii under boron stress. Soluble protein and soluble carbohydrate increased with the increasing concentration of applied boron. These results demonstrated that the two poplar species eased the boron toxicity by strengthen the metabolism of protein synthesis but the capacity of clearing up the harmful peroxide was limited, and the CAT and Gu-POD activities were inhibited under high bo-

Effect of Fertilization and Irrigation on Plant Mass Accumulation and Maize Production (Zea mays)

The efficiency levels of nitrogen fertilization on growth and yield of maize (Zea mays) at two different levels of irrigation were examined. The experimental work was carried out at the farm of the Technological Educational Institute of Kalamata. The soil characteristics include: sandy clay soil texture, 11.07% CaCO3, slightly acidic to neutral pH, non- saline, sufficient organic matter, adequate nitrogen, phosphorus, potassium and magnesium concentrations. Plot dimensions were equal to 3.0x4.0 m with four rows of plants per 0.75 cm in each plot of which the two inner rows represent the experimental surface. The experimental design was a Randomized Block Design. The experiment consisted of six treatments in three replications, with two levels of soil water capacity (70 and 40% respectively). N levels were 0, 160, 240 kg/ha, while the P and K levels were kept constant at 100 kg/ha. The amounts of P, K and 30% of N were added to the basic fertilization before sowing. The remaining N amount separated to two doses, at different growth stages of maize and incorporated through the irrigation system. The type of fertilizers was ammonium sulfate, ammonium nitrate, superphosphate and potassium sulfate. Based on the experimental data, it was found that the fed conditions greatly influence the nature and direction of the processes involved in developing plant, the addition of nutrients, regardless of treatment combination and their dosages, affected positively the plant growth, the fresh plant mass accumulation and the weight of 1000 grains compared to plants cultivated in soil without nitrogen. The total plant weight increase was equal to 59.13% compared to plants cultivated in soil with lack of nitrogen maintaining N, P, K levels to 240, 100, 100 kg/ha and soil water capacity to 70%. High seed yields were observed with the addition of 160 and 240 kg/ha N, constant levels of P and K, and 70% of soil water capacity. Low seed yields were observed when the level of irrigation was 40% of soil water capacity regardless the added amount of N, P and K. This can be interpreted that fertilizers have a high impact on crop yield, when combined with the appropriate level of irrigation.

Physiological and biochemical markers to optimize sugar mill wastewater for irrigation in maize (Zea mays L.) crop

The current study represents the effect of varying concentrations (0, 25, 50, 75, and 100 %) of sugar mill wastewater on growth, biochemistry, and physiology of two maize cultivars (Pak-Afgoi and EV-5098) at seedling, silking, and grain-filling growth stages. It was observed that lower levels of sugar mill wastewater (25 and 50 %) resulted in increase in chlorophyll contents and plant fresh and dry masses. In addition, sugar mill wastewater caused a consistent increase in RMP, SOD activity, MDA and H2O2 concentrations, and decrease in ascorbic acid concentration and activities of POD and CAT. Of the two cultivars, hazardous effects of high concentrations of sugar mill wastewater were more prominent in cv. EV-5098 that exhibited lower chlorophyll contents, fresh and dry masses and lower activities of enzymatic antioxidants and concentrations of non-enzymatic antioxidants. However, cv. Pak-Afgoi tolerated higher levels of sugar mill wastewater in terms of lower endogenous concentrations of MDA and H2O2 and better antioxidant defense system. Of different growth stages, seedling and grain-filling stages proved to be more sensitive to the application of sugar mill wastewater. Overall, the results suggested that diluted sugar mill wastewater (≤50 %) can be used safely for irrigation purpose of maize plants.

Yield of Two Hydroponically Grown Tomato Cultivars as Affected by Transplanting Stage or Direct Seeding

Direct seeding or transplanting younger seedlings should reduce costs in hydroponic systems. A 2-year study (2011–12 and 2012–13) was conducted to determine yield of two hydroponically grown tomato cultivars using transplanted seedlings at different growth stages vs. direct seeding. An open bag, using 10-L plastic bags filled with sawdust, was used for direct seeding and transplanting of seedlings at two-, four- or six-leaf stages. Data were collected on early marketable, early total, total, total marketable and cull yield as well as plant fresh and dry mass. In 2011–12, there was increased early marketable and total yields from direct-seeded plants or plants transplanted at the two- or four-leaf stage. Cultivar FA593 produced a higher early marketable yield and total yield compared with ‘Linares’. In 2012–13, the highest early marketable and total yields were for plants developed from those transplanted at the two-leaf stage or from those developed from direct seeding. There was no difference between cultivars on marketable and total yield. Cultivar Linares produced the highest plant fresh and dry mass. Early yield can be induced by direct seeding or transplanting seedlings at the two-true leaf stage with no significant effect on total yield and marketable yield. Direct-seeded plants, or transplanting seedlings at the two-leaf stage, will benefit growers by producing tomatoes earlier for the market while eliminating or reducing transplant shock.

The role of the anion in the toxicity of imidazolium ionic liquids

From the environmental protection point of view, the growing interest of ionic liquids in various industrial branches has raised concerns for the toxicity assessment of these compounds. The paper discusses the effect of salts containing the shared 1-ethyl-3-methylimidazolium [EMIM] cation as coupled with five different anions: bromide [Br], nitrate [NO3], p-toluenesulfonate (tosylate) [Ts], dimethylphosphate [dMP] and methanesulfonate [MS] on the growth and development of higher land plants – spring barley and common radish. The experiment was done according to the ISO Standard 11269-2:1995 and the OECD/OCDE Guide 208/2006. As the indications of phytotoxicity, the percentage of sprouts and the level of dry and fresh plant mass were used; in addition, the visual assessment of any signs of damage to the examined plant species, such as growth inhibition and chlorotic changes, was also made. Results of our study has proved the negative impact of ILs on the tested plants and the toxic effect of imidazolium salts was dependent primarily on the applied ionic liquids concentration. The common radish revealed the higher tolerance to the imidazolium as compared to spring barley. The anion type of ionic liquid was crucial for the toxicity against common radish.

Effect of Salt Stress on Different Growth and Biochemical Attributes in Two Canola (Brassica napus L.) Cultivars

A pot experiment was conducted to appraise the differences in salinity tolerance in two canola cultivars (Shiralec and Dunkeld). The experiment was laid out in completely randomized design with five replications. Four salinity levels [0, 120, 150, and 180 mM sodium chloride (NaCl)] were used in this study. Salt stress caused a marked decrease in plant fresh and dry masses, photosynthetic pigments, and anthocyanins and increase in malondialdehyde (MDA), hydrogen peroxide (H2O2), and leaf phenolics. We have observed that salt tolerance ability of cv. Shiralec is greater than that of Dunkeld in terms of lower salt-induced decline in fresh and dry masses, photosynthetic pigments, lower MDA, H2O2 contents, and greater leaf phenolics.

Growth, photosynthesis and ion balance of sesame (Sesamum indicum L.) genotypes in response to NaCl concentration in hydroponic solutions

A hydroponic, greenhouse experiment was conducted to assess the effects of NaCl on growth, gas-exchange parameters, chlorophyll (Chl) content, and ion distribution in seven sesame (Sesamum indicum L.) genotypes (Ardestan, Varamin, Naz-Takshakhe, Naz-Chandshakhe, Oltan, Yekta, Darab). The plants were grown in 4-L containers and subjected to varying levels of salinity (0, 30, and 60 mM NaCl). After 42 days, salt treatments induced decreases of plant fresh and dry mass, total leaf area, and plant height in all genotypes. Increasing NaCl concentration caused significant, genotypedependent decrease in the net photosynthetic rate, stomatal conductance, Chl content, and maximum quantum efficiency of photosystem II, while it increased the intercellular CO2 concentration. Based on the dry matter accumulation under salinity, the genotypes were categorized in two groups, i.e., salt-tolerant and salt-sensitive. The impact of salt on plant ion concentrations differed significantly among the sesame genotypes and between both two groups. The plant Na+ concentrations were significantly lower in Ardestan, Darab, and Varamin genotypes than those found in the remaining genotypes. The highest plant K+ and Ca2+ concentrations together with the lowest Na+/K+ and Na+/Ca2+ ratios were observed in Ardestan, Varamin, and Darab genotypes. Our results indicated the presence of differences in salt response among seven sesame genotypes. It suggested that growth and photosynthesis could depend on ion concentrations and ratios in sesame.

Assessment of aphid infestation levels in some cultivars of mustard with varying defensive traits

Phloem-sucking mustard aphid (Lipaphis erysimi) is a major pest of mustard (Brassica juncea). Pot experiment with randomised block design was conducted with five replicates of each of five cultivars (Alankar, Pusa Jai Kisan, Rohini, Sakha and Varuna) of the mustard for their degree of inherited resistance and/or susceptibility to the mustard aphid infestation. Forty-five days old (from date of sowing) pot-grown plants of all selected cultivars of mustard were exposed to 40 adult mustard aphids. The aphid-infested plants were kept in specially designed net houses of fine mesh to protect from predators and/or migration of aphids from one to other host. The aphid population and some growth attributes of the selected cultivars of mustard were recorded 15 and 30 days later (i.e. at 60 and 75 days after sowing). The aphid population multiplied more rapidly on Rohini than other four cultivars. Cultivar Alankar resisted most and supported to least number of aphid’s off-springs. Statistically analysed growth attributes (fresh plant mass, dry plant mass, protein, chlorophyll and carotenoid contents), resistance attribute (proline) and population demography of aphids revealed that some inherited characteristics of avoidance, antibiosis and repellence to herbivores helped cultivar Alankar to excel despite equal degree of aphid attacks as on other cultivars. Cultivar Rohini for the want of such resisting factors remained vulnerable to aphid herbivory. These two cultivars (Alankar and Rohini) form good research material for comparative studies on plant defences to herbivory and a tri- trophic resistance through volatile chemical signalling.

Effect of short-term exposure to red and blue light on dill plants growth

Effect of the end-of-day and the end-of-night red and blue light in dill growth was investigated. Ambrozja dill (Anethum graveolens L.) cvs were grown in vegetation chambers in completely controlled conditions exposed to white diode light. Red and blue light was employed for 30 min before the initiation or after the end of the lighting period. The values of plant fresh mass, area and height parameters were the highest for plants treated with red light at the end of night. The application of red light at the end of day exerted a similar effect on plants as the exposure of plants to blue light at the end of night. Plants treated with blue light at the end of the lighting period were characterised by the poorest growth rate. Plants additionally lighted with blue light were found to have both distinctly smaller mass as well as area in comparison with plants exposed to red light. Both methods are useful to control the plants growth depending on the phase of plant development and growers’ requirements.