Panwar Giriraj Singh, Joshi Bhavana
Botanical Survey of India, Northern Regional Centre, Dehradun, Uttarakhand, 248195, India.
J Genet Eng Biotechnol. 2020 Aug 10;18(1):40. doi: 10.1186/s43141-020-00051-9.
Tricholepis roylei Hook. f. is a bushy annual shrub of the Asteraceae family and point endemic species of the Western Himalaya. T. roylei is a critically endangered species and factors like poor seed germination and habitat destruction are further rendering the species towards extinction. Therefore, the present investigation was designed to document the seed germination potential of the species and to establish a reproducible in vitro propagation and mass multiplication protocol for the ex situ conservation of T. roylei germplasm.
Seeds of T. roylei were collected from Sangdha, Himachal Pradesh, India, and were sown in different substrates under open and controlled conditions. Though the overall seed germination potential of the species was reported to be very low and maximum 45% germination was observed in cocopeat substrate after 26 days of incubation. Half-strength Murashige and Skoog (MS) medium enriched with 6-benzylaminopurine (4.4 μM l) and naphthalene acetic acid (1.0 μM l) was observed to be the optimum medium for shoot induction in shoot tip explants of T. roylei. Maximum 98.89% shoot formation was observed with 28.42 shoots per culture and 4.4-cm shoot length, respectively. The healthy shoots (4.0 cm) were transferred onto rooting media (1/4, 1/2 and full MS) and roots were developed after 8 weeks of incubation in the half-strength MS medium. Half MS augmented with 4.9 μM l indole butyric acid was observed to be optimum for the root development and an average of 10.2 roots per shoot with 4.0-cm length was obtained. Rooted plantlets were successfully acclimatized under greenhouse conditions and subsequently established in the field, with a recorded survival rate of 90%. The plants acclimatized to the open environment were also planted in the wild under the habitat rehabilitation and species recovery programme.
The seed germination study envisages that the seed germination potential of the species is very poor and might be one of the probable factors responsible for the shrinkage of T. roylei population in the wild. The standardized micropropagation protocol can be helpful for the ex situ conservation of germplasm and rehabilitation of species in the wild. Moreover, the study could be helpful in elucidating the phytochemical and molecular analysis of species.
罗氏毛鳞菊（Tricholepis roylei Hook. f.）是菊科的一种丛生一年生灌木，是西喜马拉雅地区的特有物种。罗氏毛鳞菊是一种极度濒危物种，种子发芽率低和栖息地破坏等因素正使该物种走向灭绝。因此，本研究旨在记录该物种的种子发芽潜力，并建立一种可重复的离体繁殖和大量繁殖方案，用于罗氏毛鳞菊种质的迁地保护。
罗氏毛鳞菊的种子采自印度喜马偕尔邦的桑德哈，并在开放和受控条件下播种于不同基质中。尽管据报道该物种的总体种子发芽潜力很低，在培养26天后，椰糠基质中观察到的最高发芽率为45%。观察发现，添加6-苄基腺嘌呤（4.4 μM l）和萘乙酸（1.0 μM l）的1/2强度Murashige和Skoog（MS）培养基是罗氏毛鳞菊茎尖外植体诱导芽的最佳培养基。分别观察到最高98.89%的芽形成，每培养物有28.42个芽，芽长4.4厘米。将健康的芽（4.0厘米）转移到生根培养基（1/4、1/2和全强度MS）上，在1/2强度MS培养基中培养8周后生根。添加4.9 μM l吲哚丁酸的1/2 MS培养基被认为最适合根系发育，平均每个芽有10.2条根，根长4.0厘米。生根的小植株在温室条件下成功驯化，随后在田间定植，记录的成活率为90%。适应开放环境的植株也在栖息地恢复和物种恢复计划下种植到野外。
种子发芽研究表明，该物种的种子发芽潜力非常低，这可能是野生罗氏毛鳞菊种群数量减少的可能因素之一。标准化的微繁殖方案有助于种质的迁地保护和野外物种的恢复。此外，该研究有助于阐明该物种的植物化学和分子分析。
