​Allelopathic Chemical Screening of Aqueous Extracts of Coir Pith on Seedling Growth of Black Gram (Vigna mungo L.) and Green Gram (Vigna radiata L.)

Background: Black gram (Vigna mungo L.) and Green gram (Vigna radiata L.) were mostly used as chemical residue indicators for testing the persistence of pesticides, fungicides and herbicides, etc. in the soil. Presently, the coir pith was used as a medium of nursery for many seeds and seedling production. This study evaluated the inhibition effects and screening of allelopathic chemicals from aqueous extracts of coir pith and composting coir pith on the back gram and green gram by response index method and GCMS/MS analysis. Methods: The coir pith and composted coir pith soaked the ratio of 1:10 for 24 hrs, filtered through Whatman No.1 filter paper. The inhibition effect tested for germination and seedling growth of black gram and green gram was sown in poly pots. The carbon: nitrogen ratio and the total organic carbon were analyzed by dry combustion method, Kjeldahl method and GCMS/MS analysis. Result: The phytotoxic substances are present in coir pith, which can be exterminated by composting the coir pith for better growth and development of seedlings. The negative response index (RI), high C: N ratio and chemical compounds like tocopherol, fucoxanthin, tetramethyl heptadeca, dichloroacetamide, tetrazole, hydroxyethyl palmitate, neocurdione and uridine derivations present in raw coir may have the phytotoxic effect and produced yellowing symptoms in young plants compared to composted coir pith. This is exterminated by composting the coir pith for better growth and development of seedlings as well as used for various agricultural and horticultural nurseries.

Assessment of allelopathic potential of the salicylic acid on target plants: Euphorbia heterophylla and Bidens pilosa

Salicylic acid has one of its characteristics the allelopathic potential. The present paper, is a research quantitative in nature aimed to assess the allelopathic potential of salicylic acid to identify the best concentration range for other pure substances. The bioassays were performed in a BOD incubator, seeking to assess the seedling growth by measuring the radicle and hypocotyl length. Each bioassay occurred for 12 days. The concentrations of salicylic acid used in the bioassays were: 1000, 750, 500, 250, 125, and 62.5 ppm and control. The obtained data were submitted to the tests: Kolmogorov-Smirnov normality, the two-way ANOVA with repetition, and Tukey. Based on the results obtained, it was possible to observe that several concentrations demonstrated significant differences, i.e., there is an allelopathic activity in both species (Euphorbia heterophylla and Bidens pilosa). The highlights were for the concentrations of 750 and 1000 ppm for E. heterophylla and 500, 750 and 1000 ppm for B. pilosa. However, there was no significant difference between these concentration groups. The radicle’s length was the part most negatively affected. These results can be used to identify better concentrations for other pure substances, which are usually obtained in small quantities, being useful in the formulation of a product with characteristics of bio-herbicides.

Role of L-Ornithine in Mitigation of Salt Stress In Allium Cepa L.

Effects of L-ornithine (150 mg/l) on the germination, seedling growth, mitotic index, chromosome aberrations and micronucleus frequency of Allium cepa L. bulbs germinated at 0.125 M salinity were studied. The radicle number of the group III bulbs germinated in the medium with ornithine alone as compared to ones of the group I (control) bulbs which germinated in distilled water medium. But, their germination percentage, radicle length and fresh weight were statistically the same as ones of the group I bulbs. Besides, the micronucleus frequency and chromosomal abnormalities in the root-tip meristematic cells of the group III bulbs showed increased germination compared to ones of the group I bulbs. However, their mitotic index statistically showed the same value as the group I bulbs. Salt stress significantly inhibited the germination and seedling growth of A. cepa bulbs. Moreover, it reduced the mitotic index in the root-meristem cells of the bulbs and fairly increased the number of chromosome aberrations and micronucleus frequency. On the other hand, the inhibitive effect of salt on the germination, seedling growth, mitotic index and micronucleus frequency was dramatically alleviated in varying degrees by ornithine application. But, it was ineffective in reducing the detrimental effect of salinity on the chromosome aberrations. The germination percentage, radicle lenght, radicle number, fresh weight, mitotic index, micronucleus frequency and chromosomal aberrations of the group II seedlings grown in 0.125 M salinity were 27%, 13.5 mm, 18.4, 7.1 g, 5.5, 18.3 and 60.8%, respectively while these values became 68%, 16.4 mm, 16.4, 10.5 g, 15.6, 7.6 and 74.8% in the group IV seedlings treated with L-ornithine. Bangladesh J. Bot. 50(4): 1165-1171, 2021 (December)

A, The ALLELOPATHIC EFFECT OF CINNAMOMUM VERUM ON EMERGENCE AND SEEDLING GROWTH OF RADISH (Raphanus sativus)

Crop plants release biochemicals into surrounding environment that help in obtaining maximum yield of crop by acting bioherbicide at high concentration and plant growth hormone at low concentration. Therefore, this study was planned at Department of Agronomy in Weed Science Laboratory, University of Agriculture Faisalabad during Winter 2018 to evaluate the hermetic effects of Cinnamomum verum (Dalchini) on vegetable crop Radish (Raphanus sativus) and determination and quantification Phenolic compound present in aqueous extract of bark of C. verum. The experiments were laid out under completely randomized design (CRD) having three replications. The aqueous extracts of C. verum was used on radish seeds at different concentrations (2.5%, 5%, 10%, 20%, 40% and 80%). Data regarding seed germination and seedling growth (shoot length, root length, shoot fresh weight, root dry weigh) of radish were recorded following standard procedures. Results of our study revealed that at higher concentration act as bioherbicide and produced inhibitory effects on R. sativus while at low concentration it shows hermetic effect and promoted the seedling growth. aqueous extract showed concentration. Among different Phenolic compound (Syringic acid, p-crumeic, Ferulic acid, Quercetion and Gallic acid) determine in aqueous extract of barck of C. verum Maximum Quercetion (12.3 %) and minimum Syringic acid (0.60 %) was found. Therefore, it was concluded from this study that aqueous extract of C. verum can be used as bioherbicides at higher concentration to control weed while at low concentration as plant growth regulator.