Differential Influx of Natural Plant Growth Regulators during Embryogeny in the Recalcitrant Seeds of Syzygium cumini (L) Skeels

Background: The hormonal up-regulation and down-regulation in recalcitrant seeds, on the other hand, has received little research. We tested fou plant growth regulators from distinct families of phytohormones at the same time to better understand their differential input from maternal tissues to growing Syzygium cumini seeds. Methods: During April-June 2020, seeds were collected in their native habitats in the Western Ghats. Seeds were chosen at random from each treatment. The embryonic tissues of seeds were chopped up and frozen for LC-MS/MS hormonal profiling. Result: Except for ABA, the dynamics of key plant hormones in this recalcitrant seed were identical to that of desiccation-tolerant orthodox seeds. When compared to other conventional seeds, SA was shown to accumulate at an unusually high level in mature embryonic tissues, demonstrating the highly hydrated seed’s defense mechanism against fungal attack following seed shedding.

Impact of Plant Growth Regulators to Development of the Second Generation Energy Crop Miscanthus × giganteus Produced Two Years in Marginal Post-Military Soil

The impact of the plant growth regulators (PGRs) Stimpo, Regoplant, and Charkor on the production of the second-generation energy crop Miscanthus × giganteus on marginal post-military soil was investigated during two vegetation seasons. The land, previously a tank training polygon, has not been in use since 1990 and has become marginal. Biological parameters (stem, shoot, and root lengths) and dry biomass values were evaluated in relation to the applied treatments. The multivariate general linear model (M-GLM) results showed a positive influence of Charkor on M. × giganteus development; the effect was markedly higher in the second year of vegetation. The impact of Stimpo and Regoplant was less noticeable; nevertheless, certain combinations of treatments showed satisfactory results. The M-GLM approach detected the inter-influence of the main factors of the production process, i.e., PGRs, soil, and year of growing. The results showed the predominant influence of year, PGRs and combined factor PGRs × year on the biological parameters; the other studied factors and their combinations were not as effective. Further research should focus on verifying the field-scale results for the M. × giganteus plantation established in a post-military area and compare the lab and field studies.

​Standardization of Grafting in Bittergourd (Momordica charantia L.)

Background: Commercial cultivation of bitter gourd is affected by biotic stresses like mosaic disease, fusarium wilt and root-knot nematode as well as abiotic stress like drought. Grafting with resistant rootstocks can be a tool to control these problems. In vegetable production, grafting is exploited commercially in many parts of the world. The cultivated area of grafted solanaceae and cucubitaceae plants has increased tremendously in recent years because of the advantages of grafted plants. Commercial use of vegetable grafting is a relatively recent innovation in India and scientific information on grafting in bittergourd is meager. In this context, identification of suitable rootstocks and standardization of grafting techniques that do not have adverse effect on yield and fruit quality not only lay foundation for further evaluation on tolerance to different biotic and abiotic stresses but also enhance the area and production of bitter gourd especially in sustainable production systems. Methods: Grafting in bitter gourd was carried out with three grafting methods such as hole insertion grafting, one cotyledon grafting and cleft grafting using growth regulators viz., alar and CCC to control height of rootstocks in order to identify suitable method, growth regulator and its concentration. The grafting experiment was done independently to four cucurbitaceous rootstocks viz., sponge gourd, pumpkin, bottle gourd and bitter gourd using bittergourd var. Preethi as scion. Height and diameter of the rootstocks before grafting were recorded and then the growth regulators alar and CCC each at 10 mgL-1 and 50 mgL-1 along with distilled water as control were sprayed on rootstocks in order to prevent the lodging of the root stocks and then grafted using different methods. Days taken for graft union and percentage success were also evaluated after grafting. Result: Our study of grafting bitter gourd scion into four cucurbitaceous rootstocks utilizing three methods and two growth regulators at two different concentration along with control exhibited significant difference in graft success among the methods as well as concentration of growth regulator in all four experiments. This work can be further utilized for imparting resistance against abiotic and biotic stresses in bitter gourd by selecting suitable rootstocks.

Effect of Plant Growth Regulators on Growth and Quality Flower Production of Chrysanthemum (Chrysanthemum Indicum L.)

A field study was conceded to assess the effect of plant growth regulators on growth and quality flower production of chrysanthemum at Horticulture Research Centre (HRC), Gazipur, Bangladesh. The experiment was laid out in Randomized Complete Block Design (RCBD) with ten (10) treatments and three replications. The treatments of plant growth regulators concentration were T1-50 ppm GA3, T2-100 ppm GA3, T3-150 ppm GA3, T4-400 ppm CCC, T5-600 ppm CCC, T6-800 ppm CCC, T7-250 ppm MH, T8-500 ppm MH, T9-750 ppm MH and, T10-Control. The maximum spreading of plant (27.0 cm) was observed when plants were treated with GA3 @ 150 ppm where the minimum plant spread (16.8 cm) was recorded in plants treated with CCC @ 800 ppm. The higher number of suckers (33) per pot was produced when pots were treated with GA3 @ 150 ppm whereas, application of CCC at three different concentrations produced lower number of suckers. The highest number of flower (40) was recorded with 150 ppm GA3, where minimum number of flowers (25) per pot in 800 ppm CCC. The plants sprayed with 50 ppm GA3 took 48 days to flower initiation, whereas, it took 70 days with 750 ppm MH. the highest plants recorded (7.40 cm) with 800 ppm CCC, whereas, lowest size (6.50 cm) was obtained with the application of 500 ppm MH. The maximum vase life of flowers was recorded for the treatment 800 ppm CCC (15 days), which was at par with 13 days vase life obtained by spraying 600 ppm CCC. Therefore, it is concluded that the GA3 acted as growth promoter and the CCC acted as growth retardants on yield and quality of chrysanthemum.

Sterilization protocols and the effect of plant growth regulators on callus induction and secondary metabolites production in in vitro cultures Melia azedarach L.

Melia azedarach L. is a valuable source of antioxidants and secondary metabolites. This study is a first extensive report about the effect of different serialization protocols and plant growth regulators (PGRs) on explant disinfection efficiency, callus induction and secondary metabolites production and accumulation in callus cultures of M. azedarach L. In this regard, the effect of plant growth regulators on callus induction and secondary metabolites production were examined. In addition, different sterilization agents were evaluated for disinfection of chinaberry leaf explants. The results showed that the lowest percentage of explant contamination and browning with the highest percentage of callus induction and callus growth obtained with explants pretreated with benomyl (2 g/L) for 2 h and sterilized with 7% H2O2 for 10 min and NaOCl 2% (without pH adjustment) for 12 min. Although adjusting the pH of NaOCl to pH = 7 and 10 significantly reduced the microbial contamination and increased the percentage of contamination-free cultures of M. azedarach L., adversely influenced the explant viability and callus induction and growth. The highest percentage of callus induction obtained on the MS medium containing 3 mg/L NAA/2,4-D and 1 or 3 mg/L Kin/BAP, and the highest callus yield (1804.833 mg/explant) belonged to the MS medium supplemented with 5 mg/L 2,4-D and 5 mg/L Kin. The callus cultures grown on the MS medium supplemented with 3 mg/L NAA and 1 mg/L Kin produced the highest amount of Quercetin (2.06 mg/g fresh weight), Rutin (5.56 mg/g fresh weight) and Kaempferol (1.84 mg/g fresh weight).

Effect of antioxidants and growth regulators on shoot organogenesis in the apical meristem culture of Fragaria × ananassa (Duchesne ex Weston) Duchesne ex Rozier

The initiation of strawberries into in vitro culture is known to be complicated by the inhibition of organogenesis by phenolic oxidation products. An important role in this process is given to the selection of growth regulators that increase meristematic cell activity and shoot proliferation at the stage of organogenesis induction. The present study aims to obtain a viable apical meristem culture of garden strawberry and to study the effect of different antioxidants (reduced glutathione (RG); a new preparation, i.e., a mechanical composite (MC) on the basis of biogenic silicon and green tea catechins and plant growth regulators (6-benzylaminopurine; thidiazuron) on the initiation of axillary shoot formation in strawberry meristem culture. Terminal buds containing an apical meristem and two leaf primordia isolated from the stolons of two garden strawberry cultivars (Sunny Meadow and Festival Chamomile) were used as primary explants for the initiation of strawberries into in vitro culture. It was found for the first time that the MC exhibits higher antioxidant activity as compared to reduced glutathione, reduces darkening of initial explants, as well as enhancing regeneration up to 13.0% at p ≤ 0.05. Furthermore, the best effect on the formation of microshoots per explant is observed toward the end of material introduction into in vitro culture when combining the MC with growth regulators in the culture medium. Here, the effect of strawberry cultivar on explant regeneration and the number of microshoots per explant are insignificant. It is concluded that the procedure for using the MC as an effective antioxidant during material initiation into the culture can be applied to the large-scale in vitro propagation of garden strawberries. Moreover, the technology for obtaining the MC from plant waste is environmentally friendly, which is a significant advantage for its use in in vitro technologies.

Effects of plant growth regulators and growing media on propagation and field establishment of Stevia rebaudiana: a medicinal plant of commerce

Background Stevia rebaudiana is an economically important medicinal plant that has generated interest among the growers and pharmacologists in terms of its industrial or pharmaceutical value. For the mass production of the seedlings, easy and convenient techniques are lacking while, micro propagation was reported promising but still out of reach at farm level. The unavailability of quality planting materials due to non-viable seeds is restricting its mass commercial scale cultivation. The present study was therefore attempted to standardize the plant growth regulators and growing media to standardize the vegetative propagation protocol through cuttings for its mass multiplication in Terai region of West Bengal, India. Methods Growing media (soil, FYM, saw dust and sand) as sole and in combination and growth hormones (IAA, IBA and NAA in different concentration and a commercial formulation i.e. Totoroot© with different exposure time) were compared with control (i.e. sole soil and no hormone treatment, respectively) to standardize the nursery protocol of Stevia. Results Sand used as sole was found the best growing media for survival and growth of cuttings while, cuttings treated with commercial growth hormone formulation for 5 mins was best. Cuttings treated with commercial growth hormone formulation performed significantly better in the field with respect to survival, growth and production of leaves. Conclusion The study recommends the use of sole sand media and commercial growth hormone formulation with 5 mins exposure time for mass nursery production of Stevia cuttings in Terai zone of West Bengal due to their better performance both in the nursery and after transplanting in the field.

Evidences for newer insecticides and growth regulators resistance in field populations of Helicoverpa armigera (Lepidoptera: Noctuidae) in Karnataka, India

The prominence of Helicoverpaarmigera (Lepidoptera: Noctuidae) averse insecticide resistance was traversed in the course of 2017 in Karnataka, India. The results divulged typical resistance level prostrating in selected newer insecticides, even though exiguous higher resistance airing in insect growth regulator Novaluranwith LC 50 of and 13.02 to 18.07 ppm and 1.17 to 1.95 folds resistance) compared to newer group insecticides Spinasad, Indoxacarb, Flubendiamide, and Rynaxypyr (3.57 to 10.19 ppm, 1.01 to 1.27 fold). Raichur and Kalaburgi strains comprehend higher resistance to Novaluran and newer insecticides with exception of Flubendiamide (Raichur and Vijayapura strains), respectively, and Spinosad (Kalaburgi and Raichur strains), respectively. The morphometric parameters of larval length, pupal length, and weight were most in RCH stain (2.75 cm, 1.76.18 cm, and 0.511 g, 0.309 g) respectively, which was pursued by Kalaburgi strain. The morphometric correlation revealed that larval length was a significant positive relation with insecticide resistance which might be an influence of resistance but not merely responsible. Among newer insecticides, a significant positive correlation between Rynaxypyr and Indoxacarb was evident, similarly, Nuvaluran with Indoxacarb and Rynaxypyr as well. Usage pattern revealed that 81.67 % of farmers found to use insecticides more than the recommended dose and 70.83% have habit consecutive applications of products from the same chemical group which bears witness to developing resistance.

Manipulation of Barley Development and Flowering Time by Exogenous Application of Plant Growth Regulators

Matching flowering time to the optimal flowering period in Mediterranean cropping zones is pivotal to maximize yield. Aside from variety selection and sowing date, growers have limited options to alter development in season. Plant hormones and growth regulators are used in perennial horticultural systems to manipulate development and floral initiation. In this study, a range of plant hormonal products were tested to analyze their effects on barley (Hordeum vulgare L) development by exogenous spray applications. Plants were grown in controlled conditions under long and short photoperiods with different vernalization treatments. The gibberellin (GA) products demonstrated the greatest potential for altering development. The GA inhibitor trinexapac-ethyl was able to delay the time to flowering in genetically divergent barley cultivars by up to 200 degree days under controlled conditions. A similar delay in flowering could be achieved via application at both early (GS13) and late (GS33) stages, with higher rates delaying flowering further. Notably, trinexapac-ethyl was able to extend the duration of pre-anthesis phases of development. By contrast, GA3 was unable to accelerate development under extreme short (8 h) or long (16 h) day lengths. There was also little evidence that GA3 could reproducibly accelerate development under intermediate 10–12 h day lengths. In addition, sprays of the cytokinin 6-benzyladenine (6-BA) were unable to reduce the vernalization requirement of the winter genotype Urambie. The present study provides baseline data for plant growth regulator treatments that delay cereal development. These treatments might be extended in field studies to align flowering of early sown crops to the optimal flowering period.