Seedling Shoot Dry Weight Research Articles

Activated antioxidant enzymes-reduced malondialdehyde concentration, and improved mineral uptake-promoted watermelon seedlings growth under boron deficiency

ABSTRACTAlthough boron deficiency (BD) is a drastic disorder to the agriculture crops, its effects on watermelon still unknown. Therefore, the present study investigates the effect of BD (0 and 0.5 mg L−1) on different morphological, physiological and biochemical traits, and mineral uptake during early seedlings stage of watermelon. B-deficiency induced leaf chlorosis in watermelon initiated from the leaf margins and tips. Despite that, BD increased shoot length, and root and shoot dry weight of BD-watermelon seedlings. BD decreased leaf chlorophyll and carotenoid contents, and photosynthetic parameters without affecting quantum yield of PSII. BD significantly inhibited total soluble protein accumulation, while leaf proline content was unaffected. A significant increase in antioxidant enzyme activities in response to higher hydrogen peroxide (H2O2) generation could possibly reduced lipid peroxidation and promoted BD-watermelon plant growth. BD influenced mineral uptake variously: the induction of phosphorus (P) and zinc (Zn), and the preservation of potassium (K), calcium (Ca) and molybdenum (Mo) levels in the leaves could maintain watermelon growth; while, the inhibition of magnesium (Mg) uptake seemed to be responsible for suppressed leaf chlorophyll and photosynthesis. These results would further help in understanding the physiological pathways and mechanisms associated with BD especially in watermelon, and provide database for fertilizer recommendations in B-deficient areas.

Influence of herbicides applied postharvest in wheat stubble on control, fecundity, and progeny fitness of Kochia scoparia in the US Great Plains

Field, greenhouse, and laboratory experiments were conducted at the Montana State University Southern Agricultural Research Center, Huntley, MT, USA, in 2012 and 2013, to evaluate the effectiveness of various postharvest-applied herbicides on late-season control, fecundity, seed viability, and progeny fitness of Kochia scoparia (kochia) in wheat stubble. Paraquat + atrazine, paraquat + linuron, and paraquat + metribuzin applied at the early bloom stage were the most effective postharvest treatments for late-season control (100%) at 28 d after treatment (DAT), biomass reduction (70–73%), and seed prevention of K. scoparia, and did not differ from glyphosate, glufosinate, saflufenacil + 2, 4-D, saflufenacil + atrazine, tembotrione + atrazine, or topramezone + atrazine treatments. Dicamba alone, dicamba + 2, 4-D, or diflufenzopyr + dicamba + 2, 4-D applied at the early bloom stage were ineffective, with <70% late-season control, <45% biomass reduction, and <55% seed reduction of K. scoparia. In the absence of a postharvest herbicide, uncontrolled kochia plants at a density of 8–10 plants m−2 contributed >100,000 seeds m−2. Addition of atrazine to dicamba improved late-season control (80%) and seed reduction (78%) compared to dicamba alone, and reduced seed viability and 100-seed weight. There was no significant effect of any of the dicamba-containing herbicides applied at the early bloom stage on K. scoparia progeny fitness, including height, width, primary branches, and shoot dry weight of seedlings at 42 d after planting (DAP). The effective postharvest-applied herbicides investigated in this research should be utilized to prevent late-season K. scoparia seed bank replenishment in wheat, and as a component of herbicide resistance management program for the containment of glyphosate- and/or acetolactate synthase (ALS)-inhibitor-resistant K. scoparia in wheat-based crop rotations in the US Great Plains.

Seed Size Effects on Early Seedling Growth and Response to Applied Nitrogen in Annual Ryegrass (&amp;lt;i&amp;gt;Lolium multiflorum&amp;lt;/i&amp;gt; L.)

Use of individual plants as experimental units may be necessary when resources are limited, but inter-plant variation risks obscuring differences among treatments. Experiments were undertaken to measure the effects of seed size on seedling size and response to applied nitrogen of annual ryegrass (Lolium multiflorum L.) harvested six or nine weeks after emergence. In two series of experiments, shoot and root dry weights of seedlings increased respectively at means of 53 - 61 and 29 - 30 mg·mg-1 increase in mean seed weight. Between the largest and smallest seed sizes used in this study, there was 83% difference in shoot weight at harvest six weeks after emergence and 22% difference with harvest nine weeks after emergence. Nitrogen (N) application, in comparison, increased shoot dry weights by averages of 69% and 77% with harvests at six or nine weeks, respectively. Dry mass response to N application was similar across seed size categories in shoots or roots. A mean 30% of total seedling-N was retained in roots. Nitrogen utilization efficiency for shoot growth (increase in shoot growth per unit increase in shoot N capture) ranged from 64 mg·mg-1 with harvest six weeks after emergence to 114 mg·mg-1 with harvest at nine weeks after emergence. Delay in seedling harvest from six to nine weeks post-emergence and use of closely-graded seed can reduce variation in individual seedling size and contribute to reduction in random variation in small-scale experiments.

Effect of flooding, high temperatures and pH on germination behavior of two Iranian Knapweed (Centaurea depressa M. Bieb.) populations

To study the response of seed germination of Centaurea depressa in different conditions, three separate experiments were conducted. The first one, investigated the effect of high temperatures in ten levels (25, 60, 80, 100, 120, 140, 160, 180, 200 and 220°C); the second one, tested the effect of different acidity at seven levels (4, 5, 6, 7, 8, 9 and 10) and the third experiment, studied the different flooding duration at five levels (0, 1, 2, 4 and 8 days), on percentage and rate of germination, root and shoot length and dry weight of seedlings in two populations of Karaj and Ahvaz. Increasing flooding duration in Karaj and Ahvaz resulted a sort of reduction on before mentioned traits in both populations; so that 4 days flooding of seeds in both populations completely stopped its growth. Two seed populations germinated in all levels of acidity treatments. The maximum of germination observed in pH=7 and the minimum percentage of germination in Karaj (9.5%) and Ahvaz (11.5%) population observed respectively at 10 and 4 acidity rates. Also increasing temperature leaded a negative impact on aforementioned traits; so that, these traits get to zero point at 120 0C temperatures in both populations of Karaj and Ahvaz.

Essential Oil Compositions and Natural Herbicide Activity of Four Denaei Thyme (Thymus daenensis Celak.) Ecotypes

Denaei Thyme (Thymus daenensis Celak.) is a perennial plant from Lamiaceae family. The plant's leaves possess biological attributes that provide it with the potential to be used for medicinal purposes and newly for suppressing the growth of herbaceous plants. In this study essential oil (EO) compositions and phytotoxic effects of four T. deanensis ecotypes (ECTPs) of T. deanensis were evaluated on Amaranthus retroflexus, Avena fatua, Datura stramonium and Lepidium sativum germination and related growth traits.For this purpose, thyme plants were collected from different ecological locations of Fars Province, Iran to identify EOs content and compositions and also their phytotoxic activity. Gas chromatography (GC) and GC-Mass spectrometry (GC-MS) analysis of the EOs showed that thymol (20 - 60.5 %) and carvacrol (20.1 - 63.4 %) were the two major oil components found in the studied ECTPs. For evaluating phytotoxic activity, the concentrations, 0, 200, 400, 600, 800 and 1000 µl l-1 of the EOs were tested in vitro against seeds and their effect on germination percentage and rate, root and shoot length, fresh and dry weight of seedlings were determined. In general, higher EO concentration resulted in lower germination percentage and/or rate in all studied species. The overall results of germination test represent a reduction in germination percentage of most species at concentration of 200 µl l-1. The results reported herein suggest that herbicidal properties of the four ECTPs could be due to their EO concentrations and have potential as natural herbicides.

Major QTL for enhancing rice grain yield under lowland reproductive drought stress identified using an O. sativa/O. glaberrima introgression line

Water stress is a major abiotic stress limiting the rice production and yield stability in rainfed conditions and getting worse with the predicted global climatic change. A Backcross inbred line (BIL) population derived from Swarna/WAB 450-I-B-P-157-2-1 was screened for grain yield under reproductive stage drought stress and irrigated conditions during DS2013, WS2012 and DS2012. A major qDTY3.2 with large and consistent effect on grain yield was mapped on chromosome 3 flanked by RM14303 and RM22 across three seasons under both stress and control conditions. qDTY3.2 explained a phenotypic variance of 29.5%, 18.8% and 31.8% under drought stress during DS13, WS12 and DS12, respectively. Apart from grain yield, qDTY3.2 is also account for variation in canopy temperature during flowering and seedling shoot dry weight and drought recovery under stress conditions. Lines with QTL showed a clear grain yield advantage over lines without QTL under both stress and control conditions. Due to the consistent effect of qDTY3.2 across diverse environments and varied level of stresses makes it an appropriate candidate for MAS. Introgression of such genomic regions in to elite drought susceptible backgrounds can lead to enhancement of grain yield level to a greater extent.

English

A nursery experiment was carried out in Akure (rain forest zone), south-western Nigeria to study relative effect(s) of some organic wastes as fertilizers on growth performance, soil and leaf chemical composition of cocoa seedlings (Theobroma cacao L.) in the nursery. The experiment comprised of five treatments: Cowpea Pod Husk (CPH) (2.5 t/ha), cocoa pod husk ash (CPHA) (2.5 t/ha), kola pod husk (KPH) (2.5 t/ha), NPK15-15-15 (2.5 t/ha) and control (no fertilizer application). Each treatment was applied to 2.5 kg of soil filled polythene bags containing cocoa seedlings. The experiment was arranged in completely randomized design (CRD) with three replications. The organic wastes increased significantly (P&gt;0.05) the plant height, stem diameter, leaf area, number of leaves, fresh root and shoot weights and dry root and shoot weights of cocoa seedlings. The treatments also increased significantly (P&gt;0.05) soil and leaf N, P, K, Ca, Mg, Na, soil pH and organic matter (OM) content relative to the control. Kola pod husk (KPH) was the most effective in improving cocoa growth, leaf and soil chemical composition. Key words:&nbsp; Cocoa, growth, organic matter, NPK, cowpea pod husk, cocoa pod husk ash, kola pod husk.

Enhanced phytoremediation of toxic metals by inoculating endophytic Enterobacter sp. CBSB1 expressing bifunctional glutathione synthase

To engineer plant–bacteria symbionts for remediating complex sites contaminated with multiple metals, the bifunctional glutathione (GSH) synthase gene gcsgs was introduced into endophytic Enterobacter sp. CBSB1 to improve phytoremediation efficiency of host plant Brassica juncea. The GSH contents of shoots inoculated with CBSB1 is 0.4μMg−1 fresh weight. However, the GSH concentration of shoots with engineered CBSB1-GCSGS increased to 0.7μMg−1 fresh weight. The shoot length, fresh weight and dry weight of seedlings inoculated with CBSB1-GCSGS increased 67%, 123%, and 160%, compared with seedlings without inoculation, respectively. The Cd and Pb concentration in shoots with CBSB1-GCSGS increased 48% and 59% compared with seedlings without inoculation, respectively. The inoculation of CBSB1 and CBSB1-GCSGS could increase the Cd and Pb extraction amounts of seedlings significantly compared with those without inoculation (P<0.05), the seedlings inoculated with CBSB1-GCSGS showed the highest Cd and Pb extraction amounts. It was concluded that the gcsgs gene introduced into Enterobacter sp. CBSB1 upgraded the phytoremediation efficacy of B. juncea. So the engineered Enterobacter sp. CBSB1-GCSGS showed potentials in remediation sites contaminated with complex contaminants by inoculating into remediating plants.

Effect of Hydropriming on Field Establishment of Seedlings obtained from Primed Seeds of Boro Rice cv. Brri Dhan29

An experiment was conducted at the Seed Laboratory of the Department of Agronomy, Bangladesh Agricultural University, Mymensingh during the period from January to April 2012 to study the effect of hydropriming on field establishment of seedlings obtained from primed seeds of Boro rice cv. BRRI dhan29. Seeds were soaked in water for 0, 24, 30, 36, 42, 48, 54 and 60 hours. The incubation period was 30 hours at 35°C temperature. Seed quality viz. percent germination, mean germination time, vigor index, shoot length, root length, shoot dry weight and root dry weight of rice seedlings were measured. Plant population m-2 also recorded to understand the field establishment of primed seeds. It was observed that priming treatments had significant effect on germination and other growth parameters of rice seedlings. The highest germination, vigor index, population m-2, length of shoot and root and their weight were found at 15 and 30 DAS. The lowest mean germination time was observed from hydropriming of seeds with 30 hours soaking. On the contrary, no priming treatment showed the lowest germination, vigor index, population m-2, and the highest mean germination time. The study concludes that BRRI dhan29 rice seed could be primed for 30 hours as hydropriming improves germination and field establishment of rice seedlings of Boro rice cv. BRRI dhan29.DOI: http://dx.doi.org/10.3126/ijasbt.v1i4.9102 Int J Appl Sci Biotechnol, Vol. 1(4): 220-223

Effect of Osmopriming of Boro Rice Seeds on Field Establishment of Seedlings

An experiment was conducted at the Seed Laboratory of the Department of Agronomy, Bangladesh Agricultural University, Mymensingh during the period from January to April 2012 to study the effect of osmopriming of Boro rice seed (cv. BRRI dhan29). Seeds were soaked in 1%, 3% and 5% solutions of ZnSO4, KCl and CaCl2 for 24 hours, respectively, with 30 hours incubation at 35°C temperature. Seed quality tests such as percent germination, mean germination time, vigor index, shoot length, root length, shoot dry weight and root dry weight of rice seedlings were measured for all treatments. Population m-2 was also calculated to investigate the field establishment of primed seeds. The highest germination, vigor index, population m-2, shoot length and shoot dry weight at 15 and 30 DAS, root length at 15 DAS, root dry weight at 15 and 30 DAS and the lowest mean germination time was observed from priming of seeds with 3% ZnSO4. Exceptionally, priming with 3% CaCl2 showed the highest root length at 30 DAS. On the contrary, 3% and 5% CaCl2 priming treatment showed the lowest germination, vigor index, population m-2, shoot length and shoot dry weight at 15 and 30 DAS, root length at 15 DAS, root dry weight at 15 and 30 DAS and the highest mean germination time. It can be concluded that rice seed (cv. BRRI dhan29) can be primed with 3% ZnSO4 solution for improving germination and field establishment of rice seedlings.DOI: http://dx.doi.org/10.3126/ijasbt.v1i4.9131 Int J Appl Sci Biotechnol, Vol. 1(4): 228-232

Cytokinin-producing, plant growth-promoting rhizobacteria that confer resistance to drought stress in Platycladus orientalis container seedlings

One of the proposed mechanisms through which plant growth-promoting rhizobacteria (PGPR) enhance plant growth is the production of plant growth regulators, especially cytokinin. However, little information is available regarding cytokinin-producing PGPR inoculation on growth and water stress consistence of forest container seedlings under drought condition. This study determined the effects of Bacillus subtilis on hormone concentration, drought resistance, and plant growth under water-stressed conditions. Although no significant difference was observed under well-watered conditions, leaves of inoculated Platycladus orientalis (oriental thuja) seedlings under drought stress had higher relative water content and leaf water potential compared with those of noninoculated ones. Regardless of water supply levels, the root exudates, namely sugars, amino acids and organic acids, significantly increased because of B. subtilis inoculation. Water stress reduced shoot cytokinins by 39.14 %. However, inoculation decreased this deficit to only 10.22 %. The elevated levels of cytokinins in P. orientalis shoot were associated with higher concentration of abscisic acid (ABA). Stomatal conductance was significantly increased by B. subtilis inoculation in well-watered seedlings. However, the promoting effect of cytokinins on stomatal conductance was hampered, possibly by the combined action of elevated cytokinins and ABA. B. subtilis inoculation increased the shoot dry weight of well-watered and drought seedlings by 34.85 and 19.23 %, as well as the root by 15.445 and 13.99 %, respectively. Consequently, the root/shoot ratio significantly decreased, indicative of the greater benefits of PGPR on shoot growth than root. Thus, inoculation of cytokinin-producing PGPR in container seedlings can alleviate the drought stress and interfere with the suppression of shoot growth, showing a real potential to perform as a drought stress inhibitor in arid environments.

Emergência e crescimento inicial de plântulas de Archontophoenix cunninghamiana H. Wendl. &amp; Drude provenientes de sementes de diferentes plantas matrizes

A diversidade genética é um fator fundamental nos programas de melhoramento e seleção de plantas, dessa forma, o objetivo no trabalho foi avaliar genótipos de Archontophoenix cunninghamiana quanto à emergência e crescimento inicial das plântulas, no sentido de orientar a seleção de plantas matrizes. Os frutos maduros foram colhidos em dez plantas matrizes em Monte Alegre do Sul - SP, nos quais se avaliaram o peso e as dimensões e, nas sementes, também o peso e as dimensões, além do teor de água, emergência, índice de velocidade de emergência, diâmetro e comprimento da parte aérea e massa seca de plântulas. O delineamento utilizado foi o inteiramente casualizado e a comparação entre médias foi realizada pelo teste de Tukey (P&lt;0,05). Entre as sementes das matrizes, há diferenças nas características físicas e fisiológicas, o que possibilita a identificação e seleção de matrizes produtoras de sementes de qualidade superior.

Auxin Producing &amp;lt;i&amp;gt;Pseudomonas&amp;lt;/i&amp;gt; Strains: Biological Candidates to Modulate the Growth of &amp;lt;i&amp;gt;Triticum aestivum&amp;lt;/i&amp;gt; Beneficially

The screening of plant growth promoting rhizobacteria is a crucial step for their utilization as beneficial input in improving the crop productivity. This study was carried out to screen and evaluate the auxin producing rhizospheric isolated Pseudomonas strains for their potential to improve growth of Triticum aestivum (wheat) plant under laboratory and natural conditions. Three strains PNS-4, PNS-6 and PNS-15 were evaluated for auxin production by Salkowski’s method and further confirmed by high performance liquid chromatography (HPLC). The PNS-4, PNS-6 and PNS-15 strains were identified by I6S rRNA gene sequencing that showed maximum resemblance with Pseudomonas mendocina (99%), Pseudomonas alcaliphila (99%) and Pseudomonas sp. (99%) respectively. Selected strains were found to produce auxin with and without the amendment of exogenously applied L-tryptophan, a major precursor for auxin biosynthesis and an important constituent of plant root exudates. Efficacy of these strains on wheat plant growth was checked under laboratory and field conditions. All Pseudomonas species were found to improve the % seed germination and growth parameters (shoot length, root length, fresh weight and dry weight) of the wheat seedlings significantly (P = 0.05) as compared to the un-inoculated seedlings under laboratory condition. The biochemical parameters (total soluble protein content and endogenous auxin content) of the bacterial inoculated wheat seedling were also increased significantly than that of uninoculated ones. Under natural condition, seed bacterization also showed the significant effect (P = 0.05) on yield parameters (shoot length, number of tillers, spike length and weight of seeds in grams) of the wheat plants when compared with non-inoculated plants. Our results reported the three most promising Pseudomonas candidates and revealed the fact that experiments under laboratory and natural conditions may be helpful in selecting the best candidates as bio fertilizers for future agricultural practices.

Influence of salicylic acid pre-treatment on emergence and early seedling growth of cucumber (Cucumis sativus)under salt stress

Salicylic acid (SA) is a common, plant-produced signal molecule that is responsible for inducing tolerance to a number of biotic and abiotic stresses. An experiment was therefore conducted to test whether the application of SA at various concentrations (0, 0.25, 0.50 or 1.0 mM) through a seed-soaking method would protect cucumber (Cucumis sativus L.) seedlings subjected to salt stress. After soaking, seeds were sown in plastic trays filled with washed fine sand. The trays were then placed in the greenhouse and watered with different NaCl solutions (0, 50, 100 and 150 mM), for a period of 4 weeks. SA improved the majority of physiological (relative leaf chlorophyll content, leaf relative water content and chlorophyll fluorescence ratio) and morphological parameters (total emergence, mean emergence time, shoot and root dry weights) of cucumber seedlings subjected to salt stress. SA improved the injuries caused by salt stress by promoting K + accumulation and preventing increases in leaf electrolyte leakage and Na + contents of leaves and roots. The best protection appeared to be obtained from SA applied by seed-soaking method at 1.00 mM.

Alleviation of salinity-induced perturbations in ionic and hormonal concentrations in spring wheat through seed preconditioning in synthetic auxins

The experiments were conducted to examine the effects of seed priming in solutions (100, 150 and 200 mg L−1) of different synthetic auxins, i.e., 2,4-dichlorophenoxyacetic acid (2,4-D), 2,4,5-trichlorophenoxyacetic acid (2,4,5-T), α-naphthaleneacetic acid (NAA) on growth, grain yield, gaseous exchange characteristics, ionic and hormonal concentrations in two spring wheat (Triticum aestivum L.) cultivars MH-97 (salt intolerant) and Inqlab-91 (salt tolerant). The primed (soaked for 12 h) and non-primed seeds were sown in Petri plates in a growth room as well as in a field treated with 150 mM NaCl. Generally, all synthetic auxins did not increase germination percentage and rate in both cultivars when compared with hydropriming (control), and even decreased these attributes when applied at higher concentrations (200 mg L−1). Nonetheless, under salt stress, NAA (150 mg L−1) was most effective in increasing seedling shoot dry weight, fertile tillers per plant, number of grains per ear and grain yield in both cultivars. The plants raised from seed treated with NAA (150 mg L−1) had lower shoot [Na+] in the salt intolerant cultivar. Moreover, NAA treatment improved root [Ca2+] in both cultivars. Priming agents affected leaf free indole-3-acetic acid (IAA) and indole-3-butyric acid (IBA) concentrations differently in both cultivars. Treatment with NAA (150 mg L−1) lowered leaf free abscisic acid (ABA) and putrescine (Put) concentrations and raised salicylic acid (SA) and spermidine (Spd) concentrations in the salt intolerant cultivar. In conclusion, pre-treatment with NAA (150 mg L−1) showed consistent promotive effects on growth and grain yield in the two cultivars, which were partially attributed to the beneficial effects of NAA-priming on ionic and hormonal homeostasis under salt stress.

Salicylic acid analogues with biological activity may induce chilling tolerance of maize (Zea mays) seeds

One kind of biologically active salicylic acid (SA) analogue (acetylsalicylic acid, ASA) and two inactive compounds (4-aminosalicylic acid and 4-aminobenzoic acid), along with SA were chosen to evaluate their role in inducing chilling tolerance of two different chilling-tolerant maize ( Zea mays L.) inbred lines. These compounds were applied as seed treatments or as a hydroponic application. The results showed that four compounds had no significant effect on germination of maize seeds; however, SA or ASA soaking treatments significantly increased the root length, shoot height, and shoot and root dry weights of seedlings grown under chilling stress. Hydroponic applications of SA or ASA significantly alleviated the accumulation of malondialdehyde, hydrogen peroxide, and superoxide radicals in roots and leaves of both lines under chilling stress, and the applications also increased the photosynthetic pigments, including chlorophyll a, chlorophyll b, and carotenoids. However, 4-aminosalicylic acid and 4-aminobenzoic acid applications had no significant effect in ameliorating the growth inhibition of seedlings under chilling stress. This study showed that SA and ASA significantly induced the chilling tolerance of maize; however, 4-aminosalicylic acid and 4-aminobenzoic acid were not effective in inducing tolerance to chilling stress. The results suggest that only SA analogues with biological activity may have the ability to induce chilling tolerance of maize.

English

The purpose of this study was found out to investigate the response of some rice (Oryza sativa L.) cultivars to germination parameters under salinity stress. This study was carried out to confirm rice seedling growth performance and to examine a range of genetic variability for salinity tolerance among ten rice cultivars under seven salinity levels. A laboratory experiment was accompanied at Giza Central Seed Testing laboratory (CASC), Egypt. The results showed that rice cultivars significantly varied in means of Final Germination Percentage (FGP), Germination Rate (GR), Germination Index (GI), Vigor Index (VI), Root Length, Shoot Length, Root Fresh Weight, Shoot Fresh Weight, Root Dry Weight, Relative Dry Weight and Seedling Height Reduction. Sakha 102 and Sakha 106 had positive effects in most of studied characters while, Giza 181 cultivar had negative effects in most of germination parameters under study. Salinity levels significantly varied in all germination parameters under study except shoot dry weight character. Increasing salinity concentration from 0 to 14% NaCl gradually reduced averages of germination and seedling characters. All studied characters were significantly affected by the interaction between cultivars and salinity stress, vice versa, shoot, root fresh weight and root dry weight didn't affect by interaction. It could be established that for exploiting rice germination percentage and seedling parameters under salinity stress are recognized by using rice Sakha 102, Sakha 106, Sakha 104 and Egyptian Yasmin cultivars with increasing salinity levels up to 14% NaCl. These cultivars were more tolerant to salinity and suggested to use in breeding program for attractive rice production in Egypt . Key wordsOryza sativa, salinity concentration, germination characters, rice cultivars, seedling parameters International Journal of Agriculture Sciences ISSN: 0975-3710 & E-ISSN: 0975-9107, Volume 4, Issue 6, 2012 Introduction Rice is considered as a major cereal crop for more than 50% of the world population. There is a great shortage in rice production more than 25% of the recent production may be needed [1]. Moreover, rice ranks second after wheat crop as the national income is concerned. The excessive increase in population in Egypt needs to increase the total yield of this crop in order to overcome this lack in production through its cultivation in the newly reclaimed lands especially under saline conditions of such soil. Rice is one of the most effective and commercial means of reclaiming hundreds of thousands of hectares of saline lands in Egypt. Growth characters including shoot height, fresh weight, dry weight and leaf area of salt-stressed seedlings were inhibited, depending on rice genotypes [2]. Rice varieties showed a great variation in germination due to salinity effects. Many investigators concluded that differences among rice cultivars in germination characters and seedling parameters[3,15,17,22]. Salinity is one of the major obstacles in enhancing rice production in growing areas in Egypt. Salinity decreases final germination percentage, speed of germination and led to reduction in shoot and root length and dry weight in all varieties and the magnitude of reduction increased with increasing salinity stress [11]. Therefore, development of salt tolerance varieties has been considered as one of strategies to increase rice production in saline prone Citation: Kandil A.A., Sharief A.E. and Nassar E.S.E. (2012) Response of Some Rice (Oryza sativa L.) Cultivars to Germination Under Salinity Stress. International Journal of Agriculture Sciences, ISSN: 0975-3710 & E-ISSN: 0975-9107, Volume 4, Issue 6, pp-272-277. Copyright: Copyright©2012 Kandil A.A., Sharief A.E. and Nassar E.S.E. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution and reproduction in any medium, provided the original author and source are credited.

Crescimento de mudas de maracujazeiro-doce inoculadas com fungos micorrízicos arbusculares e bactérias diazotróficas sob diferentes doses de fósforo

Conduziu-se o experimento em casa de vegetação com o objetivo de avaliar os efeitos da inoculação de fungos micorrízicos arbusculares (FMAs) e de bactérias diazotróficas endofíticas no crescimento de mudas de maracujazeiro-doce sob diferentes doses de fósforo. O delineamento experimental foi em blocos casualizados, em arranjo fatorial 3x2x4, sendo três tratamentos com fungos: Gigaspora margarita, Glomus clarum e controle (sem fungo); dois tratamentos com bactérias: Burkholderia sp. + Burkholderia silvatlantica e controle (sem bactéria); e quatro doses de fósforo: 0; 15; 30 e 60 mg dm-3, com quatro repetições. A unidade experimental foi composta por um vaso de 3,5 dm³ com três plantas. As mudas foram produzidas a partir de sementes e transplantadas para vasos, contendo mistura de solo e areia (1:2 v:v) esterilizada. Aos noventa dias após o transplante das mudas, foram avaliados: altura, diâmetro do caule, área foliar, massa seca da parte aérea, porcentagem de raízes colonizadas por fungos e enumeração de bactérias nas raízes. Independentemente da presença de bactérias diazotróficas, a inoculação com FMAs proporcionou incrementos na altura, massa seca de parte aérea, área foliar e diâmetro do caule das mudas de maracujazeiro-doce, nas doses de 0 e 15 mg dm-3 de P. As bactérias promoveram incrementos na altura e área foliar das mudas quando associadas ao FMA G. margarita, entretanto, sem a presença dos FMAs, estas reduziram a massa seca da parte aérea, independentemente das doses de P no substrato.

Impact of Salinity on Seed Germination and Early Seedling Growth of Three Sorghum (&lt;i&gt;Sorghum biolor &lt;/i&gt;L. Moench) Cultivars

The environmental stress such as, salinity (soil or water) are serious obstacles for field crops especially in the arid and semi-arid tracts of the world. In the Sudan, with the rapid expansion of irrigated agriculture, the question of soil salinity is becoming more and more urgent for naturally salt-affected lands under cultivation and maintaining the productivity of existing irrigated areas. It could be alleviated using irrigation and crop management. However, the former approach is very expensive. The latter is economical as well as efficient and it enables to produce salt tolerant crop varieties. Also other is a need to confirm the presence of genetically based variation for salt tolerance among different varieties of a particular crop at different plant growth stages. In order to investigate salinity stress on sorghum germination indices, an experiment was carried out in Sudan from September 2011 to October 2011 at University of Kordofan, in the Crop Sciences Department Laboratory, to create salinity stress, sodium chloride (Na Cl) at the levels of 0 (as control), 2, 4, 8 and 16 dS/m and three sorghum (Sorghum bicolor L. Moench) cultivars (Arfagadamak, Wad Ahmed and Butana) were tested. Seed germination percentage, seedling root dry weight and seedling shoot dry weight were measured. Low level of salinity (2 dS/m) increased seed germination percentage, while the high levels (4, 8 and 16 dS/m) inhibited the seed germination significantly. The strongest inhibition of germination occurred at the higher salt concentrations. Growth of young seedlings was also reduced, especially at the higher salt concentrations. Wad Ahmed cultivar was found to be salt tolerant during seedling biomass production. Arfagadamak and Butana cultivars were found to be salt sensitive during seedling biomass production. The study revealed the presence of broad intra specific genetic variation in sorghum varieties for salt stress with respect to their early biomass production.

Evaluation of the effect of chitin-rich residues on the chitinolytic activity of Trichoderma harzianum: In vitro and greenhouse nursery experiments

The chitin-rich residues obtained from several industries have numerous applications in diverse fields such as biotechnology, pharmacology, medicine and agriculture. In this study, three different chitin-rich residues were evaluated with regard to enhancement of the chitinolytic activity of the mycoparasitic fungus Trichoderma harzianum, used for biological control of Fusarium oxysporum in greenhouse nurseries. Chitosan (CHIT), shrimp shell powder (SSP) and mushroom wastes (MW) activated the expression of the T. harzianum genes encoding the NAGase and chitinase activities (exc1, exc2, chit42, chit33 and chit37), the highest in vitro activities of T. harzianum being seen with MW. Under greenhouse nursery conditions, the treatments involving amendment with these residues and with T. harzianum increased the NAGase activity (between 5- and 20-times higher than peat) and the chitinase activity (between 3- and 6-times higher than peat) of the growing media and maintained the shoot dry weight of plants infected with F. oxysporum. Moreover, the incorporation of these residues into the growing media enhanced the growth (first leaf length, stem length and shoot dry weight) of muskmelon seedlings. The use of these residues with T. harzianum as amendments of growing media enhanced the growth of muskmelon seedlings and decreased the weight loss due to the pathogen, giving an added-value to these residues and enhancing their management.