Forecasting Young Apple Tree Bud Status with a Visible/Near-Infrared Spectrometer

Being able to ascertain the physiological condition of the buds on a young apple tree before bud burst could help farmers manage their orchards more efficiently, especially if they could do so without destroying the buds in the process. The experiments carried out in this study were conducted with the aim of distinguishing shoot from non-shoot buds before bud burst using a visible/near-infrared spectrometer, a device that does not destroy the buds being tested. Tests on spring-planted (April 30, 2021) trees were conducted to check shoot and non-shoot bud physiology and the winter dormancy of young ‘Jonagold’, ‘Miyabi Fuji’ and ‘Orin’ apple trees. The light absorbance of the shoot buds before bud burst was much lower than the light absorbance of the non-shoot buds as checked on the visible/near-infrared spectrometer. The highest first factor effect was determined by a PCA test conducted on shoot and non-shoot ‘Jonagold’ buds (99.9%) at a range of 640-652 nm, ‘Miyabi Fuji’ buds (99.7%) at 654-680 nm and ‘Orin’ buds (99.6%) at 704-766 nm seven days before bud burst. We also found that the highest level of accuracy, using the Classifier analysis, between shoot and non-shoot ‘Jonagold’ buds (76.6%) was one day before bud burst, for ‘Miyabi Fuji’ buds (82.1%) it was three days before and for ‘Orin’ buds (76.3%) it was two days before. These findings suggest that growers can more effectively manage the development of the young trees in their orchards with a visible/near-infrared spectrometer.

In Vitro plant regeneration from leaf explants of Tagetes erecta L.

Regeneration of multiple shoots via callus induction and organogenesis was obtained from young leaf explants of the field grown marigold (Tagetes erecta L.). Callus induction and shoot regeneration at various frequencies were observed using different concentrations and combinations of growth regulators. Highest percentage (90%) of callus formation was observed within two weeks on MS medium supplemented with 5.0 mg/l BAP with 2.5 mg/l NAA. The maximum percentage (80%) of shoot bud formation (10±0.5/callus) was obtained from MS medium containing 1.0 mg/l BAP with 0.5 mg/l kinetin. The regenerated shoots developed highest percentages (90%) of roots on half strength MS medium supplemented with 1.0 mg/l IBA. The plantlets when transferred into potsoil 80% survived. Regenerated plants were morphologically uniform with normal leaf shape and growth pattern. Bangladesh J. Sci. Ind. Res.56(2), 69-74, 2021

Confirmation of “pre-plasmolysis mediated ex-osmosis hypothesis” to obtain shoot bud morphogenesis in Catharanthus roseus

The antineoplastic herb, Catharanthus roseus is a classified high-value low-volume medicinal herb which is in global attention of scientific research for modulation of its monoterpenoid indole alkaloids (MIA) pathway through genetic engineering. These secondary metabolites are generally stored in specific types of structures/compartments due to their cytotoxic nature and designated roles in plant defense response. However, their presence can hinder the genetic engineering process used to develop transgenic plants through de novo morphogenesis and regeneration of plants from cultured cells/tissues and hence, it always remained a critical impediment in transgenic research in C. roseus. The pre-plasmolysis treatment of leaf explants can help to tackle the recalcitrant nature of leaf explant and can support the direct regeneration response by ex-osmosis that minimizes the concentration of alkaloids. Therefore, this study was performed to chase the effect of osmotic conditions on recalcitrant leaves of C. roseus engaged in vitro plant regeneration and hypothesis of alkaloids ex-osmosis is confirmed by HPLC analysis.

Optimization Studies of Culture Media for In-Vitro Clonal Micropropagation of New Grape Varieties

This article describes the effect of Gautheret, White, Heller and Murashige & Skoog mineral salts during in-vitro clonal micropropagation of new grape varieties. The optimal mineral compositions of the culture medium that support the in-vitro regeneration of isolated grape explants were identified. The grapes that were studied were the Bart and Augustine varieties. Primary grape explants were cultivated for 30 days in a non-transplanted culture. Increased regenerative activity was observed in the Murashige & Skoog and White media. Increased haemogenesis occurred and shoots regenerated. The addition of cytokinin 6-BAP to the medium for obtaining aseptic culture led to an increase in the frequency of shoot-bud production by 5 to 6 times, depending on the type of medium. Combining 6-BAP with the auxin NAA provided an additional increase in the frequency of shoot-bud production, but to a lesser extent. Adding growth regulators to the culture medium also reduced the frequency of explant necrosis. Keywords: grapes, mineral salts, culture medium, microclonal propagation, in-vitro, cytokinins, auxins

Protuberances are organized distinct regions of long-term callus: histological and transcriptomic analyses in kiwifruit

Key message Macroscopic, ultrastructural, and molecular features—like a ball shape, the presence of starch granules, and the up-regulation of genes involved in carbohydrate metabolism and secondary metabolite biosynthesis—distinguish PT regions within a callus. Abstract The modification of the mass of pluripotent cells into de novo shoot bud regeneration is highly relevant to developmental biology and for agriculture and biotechnology. This study deals with protuberances (PT), structures that appear during the organogenic long-term culturing of callus (OC) in kiwifruit. These ball-shaped regions of callus might be considered the first morphological sign of the subsequent shoot bud development. Sections of PT show the regular arrangement of some cells, especially on the surface, in contrast to the regions of OC beyond the PT. The cells of OC possess chloroplasts; however, starch granules were observed only in PTs’ plastids. Transcriptomic data revealed unique gene expression for each kind of sample: OC, PT, and PT with visible shoot buds (PT–SH). Higher expression of the gene involved in lipid (glycerol-3-phosphate acyltransferase 5 [GPAT5]), carbohydrate (granule-bound starch synthase 1 [GBSS1]), and secondary metabolite (beta-glucosidase 45 [BGL45]) pathways were detected in PT and could be proposed as the markers of these structures. The up-regulation of the regulatory associated protein of TOR (RAPTOR1) was found in PT–SH. The highest expression of the actinidain gene in leaves from two-year-old regenerated plants suggests that the synthesis of this protein takes place in fully developed organs. The findings indicate that PT and PT–SH are specific structures within OC but have more features in common with callus tissue than with organs.

Effect of Explants and Low Cost Medium on Morphogenic Response of Aerial Stem and Rhizome Bud Explants of Turmeric (Curcuma longa L.) for Plant Regeneration

This study was done to select suitable explants and low cost medium for plant regeneration of turmeric. Therefore, the different explants were excised from the aerial stems and rhizome buds and surface sterilized. The sterilized explants were cultured on MS medium fortified with 2.0 mg/l BAP. From the survived aerial stem explants, 0.5 cm long vertical half of the aerial stem explants exhibited somatic embryogenic response (69.7%). The highest morphogenic response (74%) of shoot bud initiation was observed from the top slice of the surviving rhizome bud explants. Further, Yara Mila complex fertilizer, which is an ideal granular fertilizer mixture, was used as an alternative to MS medium. Three different concentrations of Yara Mila complex fertilizer (1.0, 3.0, and 5.0 g/l ) supplemented with 2.0 mg/l BAP each were tested with the MS medium fortified with 2.0 mg/l BAP (control treatment) for in vitro establishment from aerial stem explants and top slice of the rhizome bud explants. Both explants were surface sterilized and cultured on MS medium and different concentrations of Yara Mila complex fertilizer fortified with 2.0 mg/l BAP. From the survived explants, aerial stem explants exhibited somatic embryogenic response (69.7%) and shoot bud initiation (74%) on normal MS media. The higher performances were observed in 1.0 g/l concentration of complex fertilizer incorporated medium with 51% embryogenic response from the aerial stem explants and 52.3% shoot bud formation response from the top slice of the rhizome bud. The cost of 1 kg complex fertilizer was Rs. 182. It could be concluded that complex fertilizer is a cost effective alternative medium for MS medium for in vitro propagation reducing the cost of the substituted ingredients by 99.87% in the tissue culture of turmeric.

IN VITRO REGENERATION OF LITCHI (Litchi chinensis SONN.) THROUGH SHOOT BUD CULTURE

Attempts were made to develop protocol for in vitro regeneration of litchi through axillary shoot bud cultures. The problem of microbial contamination, phenolic exudation and media browning was controlled up to some extend by pretreatment and rapid subculturing. A high frequency (51 %) shoot induction and differentiation was obtained in litchi Gola variety axillary explants on MS medium containing GA3 and BAP (1 mg/l), Kin (2 mg/l). In vitro raised shoots better proliferated in medium containing 2 mg/l BAP. BAP had positive effect on multiplication and growth of shoots but higher concentration than 2 mg/l reduced growth. Maximum rooting frequency (66.67%) with healthier roots was obtained in shoots cultured on full strength MS medium supplemented with IBA (2 mg/l). Plants with well-developed roots were transferred to soil with survival frequency of 57%. A combination of BAP and GA3 (1 mg/l), KIN (2 mg/l) was effective in establishment of cultures. While BAP (2 mg/l) and KIN (3 mg/l) was good for better flourishing in vitro raised shoots. 6-benzylaminepurine had positive effect on multiplication and growth of in vitro shoots but concentration exceeding 2 mg/l decreased growth. Full strength MS medium containing 2 mg/l IBA under dark condition promoted rooting in in vitro raised shoots. The protocol established could prove advantageous to the horticulturists and the industry for developing trees true to the parental type.