Plant Maturity Affects Flowering Ability and Flower Quality in Phalaenopsis, Focusing on Their Relationship to Carbon-to-nitrogen Ratio

In the commercial production of phalaenopsis orchids, the cultivation time after deflasking is used to describe the plant age and maturity. Carbon-to-nitrogen (C/N) ratio is often used as an indicator of plant growth and flowering potential. High C/N ratios are considered to promote reproductive growth, and low C/N ratios are associated with the early vegetative growth or even inhibiting flowering. This study investigated how plant age and maturity affected flowering ability and flower quality of phalaenopsis and their relationship to C/N ratio. The plant materials of various ages were the purple, small-flowered Phalaenopsis Sogo Lotte ‘F2510’ and white, large-flowered P. Sogo Yukidian ‘V3’, which were 2 to 7 months and 10 to 20 months after deflasking, respectively. Plants were placed under 25/20 °C for 4 months to force flowering and investigate the flowering-related parameters. The leaf C/N ratio of both varieties increased in general with the increase of plant age. The spiking (flower-stalk emergence) rate of P. Sogo Lotte ‘F2510’ 2 months after deflasking was only 42%, which indicates that these plants were not completely out of their juvenile phase, whereas that of those 3 to 7 months after deflasking was 100%, indicating that plants had acquired full flowering ability. No linear correlation was found between the C/N ratio and days to spiking, to first visible bud, to first flower open, and to 90% flower opening in the white, large-flowered P. Sogo Yukidian ‘V3’. However, there was a positive correlation between the C/N ratio and inflorescence length, flower-stalk diameter, first flower diameter, and flower count. Thus, the C/N ratio is feasible to be used as an indicator for assessing the flowering quality in phalaenopsis.

Nghiên cứu vật liệu composite thân thiện môi trường từ sợi cuống dừa nước và nhựa polyethylene tỷ trọng cao tái chế

Vật liệu composite nền polyethylen tỷ trọng cao tái chế (r-HDPE) gia cường bằng sợi cuống dừa nước (Nypa fruticans flower stalk - NFFS) được chế tạo bằng phương pháp ép nóng. Đầu tiên, các sợi sau khi tách từ NFFS được xử lý hoá học và ép tạo tấm sợi ngẫu nhiên. Tiếp theo, thùng nhựa từ HDPE được thu gom, rửa sạch, cắt nhỏ, và ép nóng để tạo tấm phẳng mỏng. Cuối cùng, tấm composite được tạo hình từ các lớp nhựa và sợi xen kẽ nhau. Cấu trúc và thành phần sợi NFFS trước và sau xử lý hoá học lần lượt được quan sát qua ảnh SEM và phân tích qua TGA. Ảnh hưởng của tỷ lệ thể tích sợi NFFS đến độ co ngót, độ bền kéo, độ bền uốn, và độ bền va đập cũng được khảo sát. Kết quả là sợi NFFS có hàm lượng cellulose ~34% với các vi sợi xếp song song. Điều thú vị là sợi NFFS không có lỗ rỗng to ở trung tâm đã tạo nên khác biệt lớn về cơ tính so với một số sợi thực vật khác. Cơ tính của vật liệu đạt cao nhất ở tỷ lệ thể tích sợi 60%, có độ bền kéo ~45 MPa, độ bền uốn ~46 MPa, và độ bền va đập ~19 KJ.m-2. Như mong đợi, kết quả này cao hơn gần gấp đôi so với kết quả cơ tính của vật liệu composite từ sợi xơ dừa ở cùng điều kiện.

Susceptibility of iris (Iridaceae) to larval infestation by Neorthacheta dissimilis (Diptera: Scathophagidae)

Neorthacheta dissimilis Malloch (Diptera: Scathophagidae) is a poorly known scathophagid fly that feeds and develops on iris (Iridaceae). A survey of its occurrence was performed at the Montréal Botanical Garden (Montréal, Québec, Canada) in 2018, 2019, and 2020. Iris species and cultivars from two subgenera, Iris and Limniris, were evaluated for larval infestation. When pooled for subgenera and years, data from 18 Iris classes revealed high levels of infestation per flower stalk, ranging from 34% to 100%. When analysed per bud or flower, levels of infestation remained high, ranging from 19% to 100%, but generally was lower than for flower stalks as the unit of replication. The mean number of N. dissimilis larvae per infested flower or bud was higher for the subgenus Limniris (1.13) than for the subgenus Iris (1.03), with a maximum of four N. dissimilis larvae per flower being observed. These figures are worrying for horticulturalists because the insect is prevalent and causes either abortion or aesthetic damages to iris flowers.

Influence of structural reinforcements on the twist-to-bend ratio of plant axes: a case study on Carex pendula

During biological evolution, plants have developed a wide variety of body plans and concepts that enable them to adapt to changing environmental conditions. The trade-off between flexural and torsional rigidity is an important example of sometimes conflicting mechanical requirements, the adaptation to which can be quantified by the dimensionless twist-to-bend ratio. Our study considers the triangular flower stalk of Carex pendula, which shows the highest twist-to-bend ratios ever measured for herbaceous plant axes. For an in-depth understanding of this peak value, we have developed geometric models reflecting the 2D setting of triangular cross-sections comprised of a parenchymatous matrix with vascular bundles surrounded by an epidermis. We analysed the mathematical models (using finite elements) to measure the effect of either reinforcements of the epidermal tissue or fibre reinforcements such as collenchyma and sclerenchyma on the twist-to-bend ratio. The change from an epidermis to a covering tissue of corky periderm increases both the flexural and the torsional rigidity and decreases the twist-to-bend ratio. Furthermore, additional individual fibre reinforcement strands located in the periphery of the cross-section and embedded in a parenchymatous ground tissue lead to a strong increase of the flexural and a weaker increase of the torsional rigidity and thus resulted in a marked increase of the twist-to-bend ratio. Within the developed model, a reinforcement by 49 sclerenchyma fibre strands or 24 collenchyma fibre strands is optimal in order to achieve high twist-to-bend ratios. Dependent on the mechanical quality of the fibres, the twist-to-bend ratio of collenchyma-reinforced axes is noticeably smaller, with collenchyma having an elastic modulus that is approximately 20 times smaller than that of sclerenchyma. Based on our mathematical models, we can thus draw conclusions regarding the influence of mechanical requirements on the development of plant axis geometry, in particular the placement of reinforcements.

Effect of Organic Nutrients and Growth Regulators on Yield and Quality of Goldenrod (Solidago canadensis L)

An Investigation was conducted to study the effect of organic inputs and growth regulators on yield and quality of goldenrod (Solidago canadensis) was conducted at the floricultural unit, Department of Horticulture, Faculty of Agriculture, Annamalai University during 2018. The experiment was laid out in randomized block design with twelve treatments, various organic inputs and growth regulators including panchagavya @ 3%, vermiwash 1:5 dilutions, humic acid @ 0.2%, GA3 @ 250 ppm, NAA @ 250 ppm were applied. The yield and quality characters were studied at different stages. The observations recorded viz., yield of flower stalks/ha, days to first flowering, length of flower stalks and weight of individual flower stalks. The results revealed that plants treated with NAA @ 250 ppm + panchagavya @ 3% (T9) was observed highest flower stalk yield (1140.02 flower stalks/ha), No. of flower stalks/plant (24.48), weight of individual flower stalks, days to first flowering. Considering the overall performance, it was found that the plants treated with NAA @ 250ppm + Panchagavya @ 3% recorded better performance with regard to growth, yield and quality characters.

Studies on the Effect of Different Plant Densities and Levels of CRF on Growth, Yield and Quality of Flowers of Statice (Limonium sinuatum L.)

A Field Experiment was conducted during Rabi season 2019-2020 at Experimental field, Department of Horticulture, Naini Agriculture Institute, Sam Higginbottom University of Agriculture, Technology and Sciences, Prayagraj (U.P.), India. The experiment was Evaluated in a Factorial randomized block design (FRBD) with three replications and 12 treatments. Among the CRF of 6g recorded significantly higher growth parameters followed by CRF of 4g, 2g and control. Spacing of 45cm x 60cm had a considerable influence on the number of leaves and length of leaves. Whereas, plant height was significantly higher with a spacing of 15cm x 30cm at all the growth stages. In flowering parameters, Controlled-release Fertilizers and spacing had a significance influence on the flowering parameters of statice. CRF of 6g per plant obtained notably higher flowering parameters like length of flower stalk and day of flower bud initiation to the day of harvesting whereas, highest delay in flower stalk initiation was observed in Control. The closer spacing of 15cm x 30cm had considerable influence on days required to flower stalk initiation/appearance, length of flower stalk and day of flower bud initiation to the day of harvesting or flowering duration. The higher yield with superior quality of flowers obtained with CRF of 6g with wider spacing of 45cm x 60cm.

Essential oil components of forest clove variants from Ambon Island, Maluku

Forest clove is native to Maluku from the non-aromatic class. Forest cloves have several variants, including the accession group with a small morphological size in the population. So far, the complete information on essential components contained in this accession group is not studied. The research aims to determine the forest clove accession group's total essential oils with small morphological sizes originating from its distribution area on Ambon Island, Maluku. The analyses were performed on flowers, flower stalks, and leaves using Gas Chromatography-Mass Spectrometry (GC-MS). The analysis results identified 11 components in the flower section, 14 components on the flower stalk, and 13 components on the leaf. The main components analysis of the heat map profile revealed that the small morphological-sized forest clove accession groups' main components were germacrene-D, α-cubebene, eugenol, δ-cadinene, α-copaene, methyl eugenol.

Impact of Plant Growth Regulators on Post Harvest Life of Cut Flowers of Gerbera (Gerbera jamesonii.B) cv. Goliath

The present investigation was carried out in premises of Biotechnology cum Tissue Culture Centre, Odisha University of Agriculture and Technology, Bhubaneswar during 2015-16 and 2016-17. The objective of the study was to standardize suitable bio regulators on post harvest life of gerbera cut flowers. Apart from control, eight treatments of growth regulators like Gibberellins (GA3) @ 100ppm and 150ppm; cycocel @ 700 ppm and 800 ppm with and without amino acid were used as foliar spray. In winter season percentage gain weight of flower stalk (19.95%), percentage gain in flower diameter (4.95%), solution uptake (33.17 ml) and vase life (13.83 days) were maximum with application of cycocel @ 700 ppm + Amino Acid while percentage gain in stalk length (1.28%) of flower in vase was maximum in Gibberellin @ 150ppm + Amino Acid. Similar trends in change in above post harvest parameters were also observed in summer and rainy season.

Induction and Proliferation of Callus in the Flower Stalk of Calanthe discolor Lindl. and its Antioxidant Properties

Purpose: This study aims to establish the appropriate conditions for induction and proliferation of callus from the flower stalk of Calanthe discolor Lindl. (CFS) and to analyze the antioxidant properties as well as the skin irritation level of its extracts.Methods: Murashige & Skoog medium was used to induce the callus from CFS with NB0 (α-naphthaleneacetic acid (NAA) 0 mg/L, benzyl adenine (BA) 0 mg/L), NB1 (NAA 0.2 mg/L, BA 0.1 mg/L), NB5 (NAA 0.2 mg/L, BA 0.5 mg/L), and NB10 (0.2 mg/L, BA 1.0 mg/L) as plant growth regulators (PGR). The callus powder was extracted by ultrasonic treatment, and the total phenolic contents (TPC), 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity, and human skin irritation test using callus extracts were performed.Results: As a result of callus induction from CFS with PGR, NB5 showed the highest growth rate of callus with a weight of 4.2±0.3 g. The TPC of the callus extracts NB0, NB1, NB5, and NB10 were 33.71±0.27, 37.59±0.51, 46.26±0.18, and 55.92±0.33 mg GAE/g, respectively. NB10 showed the highest value of DPPH radical scavenging activity than that of NB0, NB1, NB5, and NB10, in various concentrations. CFS callus extract showed very low human skin irritation compared to that of the control group, 10% SLS.Conclusion: The optimal PGR condition for induction of CFS callus was established as NB10. CFS callus extracts can be used as functional materials for cosmetics as it has significant antioxidant activity and low skin irritation value.

Studies on Varietal Diversity and Selection of Potential Varieties of Gerbera (Gerbera Jamesonii H. Bolus Ex Hook. F.) For Commercial Cultivation in Bangladesh

Ten commercial genotypes of Gerbera jamesonii were evaluated for a number of qualitative and quantitative traits in RCBD at the Botanical Garden of Jahangirnagar University, Savar, Dhaka. Qualitative morphology among 10 genotypes showed significant similarities and dissimilarities. The analysis of variance for all the quantitative traits showed highly significant variations among the genotypes. Genotypes Dutch Diva, Classic Fabio Gold, Candela and Dune proved to be the most suitable and sustainable as they were the best performer for different growth and flower quality parameters. Number of flowers per plant found best in Candela and Dutch Diva (11.33). The phenotypic coefficients of variation (PCV) were found higher than the genotypic coefficients of variation (GCV) for all characters. Maximum GCV and PCV were observed for number of suckers per plant (30.984 and 39.568) followed by number of whorls of ray florets per flower and days to flowering from bud initiation. High heritability values were obtained for all the characters. In high heritability estimate coupled with high genetic advance as percentage of mean was maximum for days to first flowering (32.442), plant height (cm) (17.026) and number of suckers per plant (15.992). Selection would be effective for the character showing high performance in genetic parameter. Path analysis revealed that the diameter of disc florets per flower, stalk girth (cm), number of disc florets per flower, number of ray florets per flower would be selection criteria for improvement in flower number. Based on D2 statistics, 10 genotypes were grouped into 3 clusters, namely cluster I, II and III. Highest number of genotypes was found in cluster I containing 5 genotypes. Scatter diagram represents pattern of genotypic distribution into clustering through principal component scores. Highest inter-cluster distance (22.94) was observed between cluster I and III. The genotypes of cluster II possessed heterogeneous nature and showed highest intra-cluster distance (11.35). Highest cluster mean was observed in cluster II containing four genotypes regarded as the superior than another cluster. Bangladesh J. Bot. 50(3): 541-550, 2021 (September)