Main conclusion: Shoot tip necrosis is a physiological condition that negatively impacts the growth and development of in vitro plant shoot cultures across a wide range of species. Shoot tip necrosis is a physiological condition and disorder that can arise in plantlets or shoots in vitro that results in death of the shoot tip. This condition, which can spread basipetally and affect the emergence of axillary shoots from buds lower down the stem, is due to the cessation of apical dominance. STN can occur at both shoot multiplication and rooting stages. One of the most common factors that cause STN is nutrient deficiency or imbalance. Moreover, the presence or absence of plant growth regulators (auxins or cytokinins) at specific developmental stages may impact STN. The cytokinin to auxin ratio within an in vitro plant can be modified by varying the concentration of cytokinins used in the culture medium. The supply of nutrients to in vitro shoots or plantlets might also affect their hormonal balance, thus modifying the occurrence of STN. High relative humidity within culture vessels and hyperhydricity are associated with STN. An adequate supply of calcium as the divalent cation (Ca2+) can hinder STN by inhibiting the accumulation of phenolic compounds and thus programmed cell death. Moreover, the level of Ca2+affects auxin transport and ethylene production, and higher ethylene production, which can occur as a result of high relative humidity in or poor ventilation of the in vitro culture vessel, induces STN. High relative humidity can decrease the mobility of Ca2+within a plant, resulting in Ca2+deficiency and STN. STN of in vitro shoots or plantlets can be halted or reversed by altering the basal medium, mainly the concentration of Ca2+, adjusting the levels of auxins or cytokinins, or modifying culture conditions. This review examines the literature related to STN, seeks to discover the associated factors and relations between them, proposes practical solutions, and attempts to better understand the mechanism(s) underlying this condition in vitro.
Societal Impact Statement: Rafflesia is the genus that contains the world's largest flowers. Despite their global appeal, most of the 42 known species are now at risk of extinction. Urgent action is needed to protect these remarkable flowers. A combined approach to conservation is recommended, including a greater level of habitat protection and support for local community action groups. Rafflesia is a suitable new icon for conservation in the Asian tropics.Summary: The genus Rafflesia, which includes the world's largest flowers, has aroused curiosity among scientists for centuries and features prominently in local culture across Southeast Asia. The plant has long been used in ethnobotanical medicine and, more recently, as a source of revenue from ecotourism. But despite its acclaim, Rafflesia remains poorly understood in many respects. Taxonomy is disputed, new species are described each year, and the plant has proven recalcitrant to cultivation. This has hindered conservation, and most of the 42 known species are now severely threatened, yet only one is listed by the International Union for Conservation of Nature (IUCN). We estimate that 60% of Rafflesia species face a severe risk of extinction (equivalent to Critically Endangered [CR]). Moreover, we predict that at least 67% of known habitats fall outside protected areas, exacerbating their vulnerability. Alarmingly, recent observations suggest taxa are still being eradicated before they are even known to science. We present recent scientific discoveries and probable extinctions and highlight case studies of conservation success, with a focus on the role of local people. We propose a multi‐pronged conservation approach combining strengthened taxonomy, ex situ propagation, ecotourism, and an extension of protected areas. We suggest action devolved to local communities and awareness campaigns linked to social media networks will be crucial outside of protected jurisdictions. Finally, we propose to establish Rafflesia as a new icon for plant conservation in the Asian tropics. A combined approach might just save some of the world's most remarkable flowers, most of which are now on the brink of being lost.
Synthetic biology has gained many interest around the globe in the last two decades, not only due to its rapid development but also the potential to provide addressable solutions using standardized design of biological systems. Considering its huge population, biodiversity, and natural resources, Indonesia could play an important role in shaping the future of synthetic biology towards a sustainable bio-circular economy. Here, we provide an overview of synthetic biology development in Indonesia, especially on exploring the potential of our biodiversity. We also discuss some potentials of synthetic biology in solving national issues. Furthermore, we also provide the projection and future landscape of synthetic biology development in Indonesia. In addition, we briefly explain the potential challenges that may arise during the development.