Morpho-anatomical appraisal of some pulse crops under salinity stress

The experiment was conducted at the field and laboratory of the Department of Crop Botany, Bangabandhu Sheikh Mujibur Rahman Agricultural University, Salna, Gazipur during the period from December 2016 to March 2017 to find out the morpho-anatomical appraisal of some pulse crops of Fabaceae family under salinity stress. Seven pulse crops viz., Lentil var. BARI Masur-7, Mungbean var. BARI Mung- 6, Blackgram var. BARI Maskalai-1, Chickpea var. BARI Chola-9, Field pea var. BARI Motor-1, Grasspea var. BARI Khesari-3 and Cowpea var. BARI Felon-2; two levels of salinity 0 and 8 dSm-1were imposed as experimental treatments. It was laid out in a completely randomized design with three replications. The NaCl was directly mixed to the dry soil. The soil (6 kg pot-1) of each treatment was placed in plastic pots with drainage holes in the bottom. The results of the experiment revealed that, salt stress caused decrease in morphological attributes and also changed anatomical features. There was a significant variation in relative values (%) of plant height, root length (%) root dry matter (%) and shoot dry matter (%) of seven selected pulse crop varieties due to the salinity stress. The highest percentage of relative plant height (92), relative root length (98), relative root dry weight (89) and relative shoot dry weight (72.8) were observed in cowpea followed by grass pea and the lowest percentage of relative plant height (51), relative root length (56), relative root dry weight (54) and relative shoot dry weight (48) were observed in lentil. The stem anatomical features were found similar changes in xylem and phloem area. Among the pulse crop varieties, cowpea and grass pea were performed better whereas lentil and black gram were found more susceptible species than the others according to their morphological and anatomical attributes. Bangladesh J. Agril. Res. 44(3): 439-451, September 2019

Prevalence of Short Dental Roots in Four Ethnic Groups in an Orthodontic Population

The purpose of the current study was to investigate if a significant relationship exists between ethnicity, sex, and short dental roots. The hypotheses are: 1. Hispanics have a higher prevalence of short dental roots than Caucasians, African Americans, and Asians; and 2. Females have a higher prevalence of short dental roots than males. The experimental groups consisted of 30 Caucasians, 30 Hispanics, 30 African Americans, and 26 Asian subjects who presented to University of Illinois Department of Orthodontics for treatment. Actual root length (mm) and relative root length were measured on periapical radiographs, for the maxillary and mandibular central and lateral incisors, and second premolars. The results showed that Asians had the shortest dental root lengths for all teeth measured, except the maxillary second premolar. Significant differences in relative root length values between the ethnic groups were found for the maxillary central incisor and second premolar. Females had shorter roots than their male counterparts within each ethnic group.

Distinct impacts of air and root-zone temperatures on leaf and root features of cucumber seedlings: resource acquisition capacity, organ size and carbon-nitrogen balance

ABSTRACTBoth low air (Tair) and root-zone (Troot) temperatures can inhibit resource (e.g. carbon and nutrients) acquisition by leaves and roots through various aspects, such as morphology, biomass allocation and assimilation/absorption capacity. However, it is still ambiguous whetherTairandTrootinfluence carbon (C) and nutrient acquisition via the same approach. To this end, in this study, cucumber (Cucumis sativusL.) seedlings were hydroponically grown under treatments arranged in complete factorial combination of two levels ofTair(26/18°C and 20/12°C, day/night) and two levels ofTroot(19°C and 13°C, constant). In general, bothTairandTrootaffected leaf and root sizes mainly by regulating their morphology rather than biomass investment. Under lowTairconditions (20/18°C), elevatedTroot(compare 19°C versus 13°C) did not influence C acquisition, but increased nitrogen (N) acquisition mainly due to an increase in relative root length, resulting in decreased C : N acquisition ratio. However, under lowTrootconditions (13°C), elevatedTair(compare 26/18°C versus 20/12°C) enhanced both C and N acquisition mainly because of an increase of both C assimilation in leaves and N absorption by roots, resulting in relatively constant C : N acquisition ratio. In addition, theTairandTrootinteraction was mainly observed in relative growth rate and root growth-related variables. Our results infer thatTairandTroothave distinct impacts on resource acquisition and carbon-nitrogen balance in plants.

Establishment of evaluation procedure for soybean seed-flooding tolerance and its application to screening for tolerant germplasm sources

The experiments concluded 48hrs for germination testing as most appropriate stress duration. Using paper roll for recording the traits was the best method than petri dish and towel method. Among the traits relative germination rate (RGR), relative seedling length (RSL), relative root length (RRL), relative root fresh weight (RRFW) and relative root dry weight (RRDW) were proved to be flooding-responsive. RSL was chosen as the major seed-flooding indicator due to higher heritability (h2), genotypic coefficient of variation (GCV), correlation with other indicators and easier measuring procedure, while RRL was considered as the subsidiary indicator. Thus, the RSL in paper roll after 48hrs seed-flooding was recognized as standard seed-flooding testing procedure and used to evaluate breeding materials. Among the 11 cultivars, the superior seed-flooding-tolerant ones were M8206, NN1138-2 and ZXD, while ten best lines were evaluated from one hundred breeding lines.

Toleransi Beberapa Genotipe Gandum (Triticum aestivum L.) Terhadap Kekeringan pada Stadia Perkecambahan

ABSTRACT<br /><br />Drought is a major abiotic stress impeding wheat production world wide. Selection of potentially drought tolerant genotypes are necessary for wheat improvement. The objective of this study was to test the tolerance level of nine wheat genotypes to drought stress at germination stage. Assesment at germination stage using osmoticum solution is an effective method for selecting tolerant genotypes to drougt stress in a short period of time. The experiment was arranged on a randomized complete block design with two factors and three replications. The first factor was wheat genotype consisted of Nias, Selayar, Dewata, H-20, Munal, SBD, SBR, S-03, and YMH. The second factor was concentration of PEG 6000 consisted of 0, 5, 10, 15, and 20%. Observation variables were germination percentage, shoot length, root length, number of root, number of leaf, seedling fresh weight, and seedling dry weight. Increasing level of PEG concentration inhibited the growth of wheat seedling. Based on the highes R2 value on the regression analysis, relative root length can be used as selection character. Based on RD50 value of relative root length, 15% PEG was determined concentration to select drought tolerant on wheat genotypes. Nias genotype was identified as tolerant genotype, while SBD, S-03, YMH, and Munal were identified as drought sensitive genotypes.<br /><br />Keywords: abiotic stress, osmotic potential, Polyethylene Glycol, RD50, relative root length

Tolerance to ion toxicities enhances wheat grain yield in acid soils prone to drought and transient waterlogging

The ion toxicities of aluminium (Al), manganese (Mn) and iron (Fe) induced in transiently waterlogged acid soils decrease root and shoot growth and grain yield more in intolerant than tolerant wheat genotypes. Whether these tolerances might also enhance grain yield in moisture-limited acid soils is not known. Wheat genotypes contrasting in ion toxicity tolerances (differing 6-fold for Al, 14-fold for Mn and 2.7-fold for Fe tolerance, quantified via relative root length (Al) or relative root dry weight (Mn and Fe)), but otherwise having a similar yield potential and maturity, were evaluated in plots with and without lime in multi-location field experiments (including two dry and one non-moisture-limiting site) in the Western Australian wheatbelt. Liming reduced surface soil acidity, and increased grain yield more in ion-toxicity tolerant than intolerant genotypes. The combined adverse effect of soil acidity and drought reduced relative grain yield less in Al- and Mn-tolerant genotypes (68%, 2347 kg ha–1) than intolerant genotypes (76%, 2861 kg ha–1) in drought-stressed environments. It appears that a deep root system to allow uptake of water from deep horizons in acidic soils with a dry surface layer is contingent on tolerance to multiple ion toxicities.

Variability in the response of pearl millet [Pennisetum americanum (L.) Leeke] accessions to salinity

The objective of this project was to develop understanding about the possibility of improving salt tolerance in pearl millet using selection and breeding methods. A collection of 143 pearl millet accessions was obtained from nineteen countries in different regions of the world, mostly from dry hot environments, e.g. Yemen, Sudan, the Central African Republic and Niger. Considerable genetic variability was found in these accessions for salt tolerance. Based upon a preliminary examination of the responses to NaCl solution in a selection of accessions, it was decided that 160 mM NaCl would be the reference parameter for assessing tolerance. The six most salt-tolerant accessions were 10876 and 10878 from Sudan, 18406 and 18570 from Namibia, and ICMV-93753 and ICMV-94474 from India, all of which had relative root lengths of above 70%. Accessions 213011 and 21351 were very sensitive, their relative root length being below 30%. Unfortunately, the areas from which the tolerant accessions from Sudan, Namibia and India originated are not known, but it is possible that they may have inhabited dry, saline lands.

Effects of calcium and aluminum in the soil solution of acid, surface soils on root elongation of mungbean

Short term root growth bioassays using mungbean (Vigna radiata (L.) Wilczek) were conducted on 39 surface soils in the unamended state and following the addition of CaCO3 or CaSO4.2H2O. Root length after 48 h growth was related to solid phase and soil solution Ca and Al attributes. Suitable diagnostic indices for the prediction of Ca limitations to root growth were either Ca saturation of the cation exchange capacity or Ca activity ratio (CAR) defined as the ratio of the activity of ca2+ in the soil solution to the summed activities of Ca2+, Mg2+, Na+, K+ and Al3+. Values corresponding to 90% relative root length were 34% for Ca saturation and 0.10 for CAR. The activities of Al3+ and AlOH2+ were the Al attributes most strongly correlated with root growth; an Al3+ activity of 1.9 �m~ and an AlOH2+ activity of 0.46 �m corresponded to 90% relative root length. The results suggest that organically complexed Al and the ion pairs Al(OH)+2, Al(OH)04 and AlSO+4 are not plant-toxic. The most effective diagnostic criterion for A1 toxicity in this study was the calcium-aluminium balance (CAB), defined as 2 log(Ca2+) - 6 log(Al3+). The CAB value corresponding to 90% relative root length was 31. The correlation between root growth and CAB was further improved by inclusion of a pH term; this may indicate toxic effects of H+ per se.

UJI KETAHANAN TERHADAP ALUMINIUM DAN pH RENDAH PADA JAGUNG (Zea mays L) VARIETAS PIONEER DAN SRIKANDI SECARA IN VITRO

One effort to increase maize productivity is by using marginal land for maize plantation. The marginal land that can be used is acid soil, but the problem are Al toxicity and low pH. To cope with these problems, cultivars having tolerance to Al toxicity and low pH are needed. Plant material used in this research were two maize varieties (Pioneer and Srikandi). Media selection is used there are 4 doses treatment aluminium (0, 250, 500 and 750 ppm AlCl3). All variables were observed except at the variable width of the leaf in this results showed that the treatment of aluminium (AlCl3) would not influence. Treatment combination Variety Srikandi and 250 ppm AlCl3 produces plant height, leaf length and leaf width is the shortest compared to other treatments. Variety Pioneer and Srikandi are suspected of varieties resistant aluminum and low pH values based on relative root length.