Effects of salinity and food on growth and survival rate of mangrove snail (\(\textit{Nerita balteata}\) Reeve, 1885) at the spat larvae stage

Mangrove snail (Nerita balteata) belongs to gastropoda species distributed in the coastal intertidal and offshore islands of Quang Ninh province. Although the artificial seeds production of this species have been successful but still having a bottle neck as a low survival rate in the process by veliger larvae are transformed into spat larvae stage. Experiments were conducted to determine effects of salinity and food on growth rate and survival rate of mangrove snail in the stage of spat larvae in Quang Ninh province. The results showed that the optimal salinity for growth and developtment of spat larvae was 25‰ that resulted in a absoluted growth rate of 16.5 ± 2.19 µm/day and survival rate of 26.5 ± 0.57% and significantly higher compared to other treatments. The diet of benthic microalgae (Navicula sp.) combined with formulated feed (AP0 and Frippak) were most suitable for the growth and development of mangrove snail at the spat larvae stage with absoluted growth rate of 25,7 ± 1,28 µm/day; Whereas the survival rate of larvae of 32,3 ± 2,52% was significantly higher than those in the other treatments.

Impact of Encapsulation on Plantlet Regeneration from in vitro Grown Shoot tips of Citrus aurantifolia (Lime)

In order to conserve diverse species of citrus, an experiment on in vitro micropropagation and production of synthetic seeds from in vitro regenerated plant propagules of the species; Citrus aurantifolia (Lime) was carried out in which shoot tips were found to be suitable for excapsulation of artificial seeds. Highest rate of germination was obtained from the shoot tips when MS was supplemented with 1 mg/l BAP. Beaded shoot tips produced maximum germination (81.43%). Germinated synthetic seeds with well established roots and shoots were were taken out from the culture bottles and transferred in plastic cups containing a mixture of sterile soil: sand and farmyard manure at a ratio of 1:1:1. Seedlings were further shifted in earthen pots and kept in a partial shed net house for 7 days. Those seedlings were finally transferred under the field conditions for acclimatization. Plant Tissue Cult. & Biotech. 31(1): 43-49, 2021 (June)

Synthetic seed technology for encapsulation and regrowth of in vitro-derived shoot-tips and somatic embryos of Asparagus officinalis L

Apical buds obtained from Asparagus plant vitro culture and somatic embryos obtained from stem cultivation, explants in MS medium supplemented with mg¹ᶫ 1, 2, 4-D and mg¹ᶫ 1 and Kinetin have been used in this research to produce artificial seeds. We encapsulated apical buds and somatic embryo using 2% sodium alginate and calcium chloride to prepare the artificial seeds. We placed artificial seeds at room temperature (about 25 ° C), in the cold, the temperature of 4 ° C and -18 ° C for different times (15,30,60,90 days) and evaluated the growing power of these seeds in MS and ½MS mediums for further investigations about the viability of seeds. The highest conversion percentage of seedlings in encapsulated embryos (70.01) was related to seed harvested from embryos treated with BA and the highest conversion percentage of seedlings in apical buds (96.54) was obtained from cultivated untreated seeds in MS medium. Encapsulated arteries and buds maintained germination energy and viability with increasing storage time after 90 days of storage at 4 and 25 ° C despite viability reduction while un-capsulated embryos and buds completely lost viability after 60 days of storage at 4 and 25 ° C and seeds stored at -18 ° C completely lost viability after 15 days of storage. In general, the percentage of seed germination and conversion to seedling is higher in seeds cultivated in MS medium compared to seeds cultivated in ½MS medium.

A comparative study on the effects of ultrasound and some growth factors on somatic embryogenesis and artificial seed production in cucumber (Cucumis sativus L.)

Cucumber (Cucumis sativus L.), a popular vegetable crop of the family Cucurbitaceae, is cultivated in different parts of the world and is of great economic importance. Ultrasound is known as a physical stimulus that can affect living systems. At the right frequency and exposure period, these waves have desired effects. In the present study, 2-week-old plants, were put in an ultrasonic bath with a nominal frequency of 40 kHz, a central frequency of 34/722 kHz and a bandwidth of 320 Hz for 0, 5, 10 and 15 minutes. Hypocotyl pieces were used as explants and cultured in Murashige and Skoog medium supplemented with 0/5 mg/l each of 2,4-dichlorophenoxyacetic acid, 1-Naphthalene acetic acid, kinetin and 6-benzylaminopurine. The use of ultrasonication at a nominal frequency of 40 kHz for 10 minutes showed better results as compared with the samples treated for 0, 5 and 15 minutes, in terms of the shape, maturity of the embryos, and also the germination of artificial seeds and maturing to flowering stage. Since the cucumber of Esfahan is very famous for its aroma and taste and it is somewhat at risk of extinction, we studied the production of artificial seeds of this valuable plant using somatic embryos and apical buds. This research is the first report on investigation of the positive effect of ultrasound on somatic embryogenesis and artificial seed production. our results clearly showed that this method is a practical method to accelerate seed germination and flowering stage.

Regeneration of Viburnum dentatum L. from Alginate-Encapsulated Shoot Explants after Short-Term Cold Storage and Assessment of Genetic Stability Using ISSR Analysis

The present study demonstrates an efficient protocol for alginate encapsulation, interim cold storing of artificial seeds and conversion to genetically stable plants of Viburnum dentatum L. “Lucidum Aiton”. Explants of shoot tips and first-node segments, excised from in vitro-derived viburnum microshoots, were encapsulated in 2.5% sodium alginate mixed with liquid MS nutrient medium and hardened in 50 mM of calcium chloride producing solid, soft and uniform beads. These artificial seeds achieved 28.9% germination under light, forming 4.3 microshoots per bead. However, with 100 mM of calcium chloride for hardening, the beads were firm and of a uniform globular shape and suitable for handling and exhibited a germination response of 48.9%. Encapsulated shoot tip explants of viburnum, which were stored at 4 °C for 4, 8 or 12 weeks, showed a gradual decline in regeneration response (73.3, 62.2, 51.1%, respectively), while non-encapsulated explants, stored under same conditions, did not survive after the fourth week of cold storage. Microshoots from cold-stored encapsulated explants, which were rooted in solid MS nutrient medium with 0.5 μΜ of Indole-3-acetic acid (IAA) and transplanted to a substrate of peat-perlite (3:1, v/v), acclimatized successfully after application of 75 or 50% shading, which was gradually reduced, and were established with minimum losses in a greenhouse. For the genetic stability of the artificial seed-derived plantlets and compared with the mother plant, an assessment was conducted using Inter Simple Sequence Repeats (ISSRs) analysis. The ISSR profiles proved the genetic uniformity and clonal stability of the regenerated plantlets and their genetic resemblance to the mother plant. The present regeneration procedure could be used as an alternative method for the micropropagation of V. dentatum.

Study on Artificial Seeds of Plants

The establishment and development of artificial seed technology is to quickly reproduce excellent varieties or hybrids, which can be applied to hybrid generation seeds produced by the three-two line method. For some varieties that are difficult to propagate with seeds or plant species with unstable genetic traits and poor fertility, artificial seed technology can also be used for mass reproduction. In particular, some new plants created through genetic engineering, such as somatic hybrids or transgenic plants, can be propagated or maintained by artificial seed technology. In addition, artificial seed technology can be used for the maintenance and rapid propagation of virus-free seedlings. Compared with ordinary test tube seedlings, artificial seeds have low cost, convenient transportation, and to a certain extent reduce vitrified seedlings. In particular, the production of artificial seeds does not occupy a large amount of soil. It can be produced all year round. Therefore, the research on artificial seeds has developed rapidly in the world.