Regeneration and Endogenous Phytohormone Responses to High-Temperature Stress Drive Recruitment Success in Hemiepiphytic Fig Species

Exposure to high-temperature stress (HTS) during early regeneration in plants can profoundly shape seed germination, seedling growth, and development, thereby providing stress resilience. In this study, we assessed how the timing of HTS, which was implemented as 8 h in 40°C, could affect the early regeneration stages and phytohormone concentration of four hemiepiphytic (Hs) and four non-hemiepiphytic (NHs) Ficus species. Their seed germination, seedling emergence, and seedling survival probabilities and the concentrations of three endogenous phytohormones, abscisic acid (ABA), indole-3-acetic acid (IAA), and salicylic acid (SA) were assessed after HTS imposed during imbibition, germination, and emergence. In both groups, seeds were more sensitive to HTS in the early regeneration process; stress experienced during imbibition affected emergence and survival, and stress experienced during germination affected subsequent emergence. There was no effect from HTS when received after emergence. Survival was highest in hemiepiphytes regardless of the HTS treatment. The phytohormones showed growth form- and regeneration stage-specific responses to HTS. Due to the HTS treatment, both SA and ABA levels decreased in non-hemiepiphytes during imbibition and germination; during germination, IAA increased in hemiepiphytes but was reduced in non-hemiepiphytes. Due to the HTS treatment experienced during emergence ABA and IAA concentrations were greater for hemiepiphytes but an opposite effect was seen in the two growth forms for the SA concentration. Our study showed that the two growth forms have different strategies for regulating their growth and development in the early regeneration stages in order to respond to HTS. The ability to respond to HTS is an ecologically important functional trait that allows plant species to appropriately time their seed germination and seedling development. Flexibility in modulating species regeneration in response to HTS in these subtropical and tropical Ficus species could provide greater community resilience under climate change.

Dynamics of vegetation structure and composition within early regeneration forest in the Danau Bangko Protected Area, Jambi, Indonesia

An analysis of the growth dynamics of a 1-ha (100 m x 100 m) permanent plot was carried out in the Danau Bangko Protected Area (DBPA) in March 2020. DBPA is part of the industrial plantation forest concession of PT Rimba Hutani Mas (PT RHM) in Jambi Province. The study aims to determine the dynamics of vegetation structure and composition between 2018 and 2020 in early regeneration forest. All trees tagged in 2018 were remeasured in 2020. Trees that had not been tagged previously but were 10 cm in diameter at breast height (DBH) were identified as a new recruit and tagged with a new number. Observations and data analysis were carried out on three stages of growth phases, namely in the tree phase ( 10 cm DBH), sapling phase (10 cm DBH), and seedling phase (height 1.5 m). The results showed that the number of species, genera, and families within the tree and sapling phases were high, but were low in the seedling phase. The dominant species in the tree phase in 2018, Alseodaphne bancana, had been replaced by Archidendron bubalinum in 2020, whereas the dominant species in the sapling phase (Rothmania sp.) and seedling phase (Aporusa microsphaera) remained the same from 2018 to 2020 . Mortality rates in all growth phases (tree, sapling and seedling) together is 4.67%. Recruitment into the tree phase from 2018 to 2020 was 2.67%, consisting of eight species, eight genera, and seven families. Within one hectare permanent plot, all members of each tree species were distributed randomly. The vertical structure of the forest area is dominated by stratum C (4-20 m height). The results of hypothesis testing for each phase (tree, sapling, seedling) were different, however overall the results showed that the plot structure and composition had changed. Studi dinamika hutan dilakukan di Kawasan Lindung Danau Bangko (KLDB) pada Maret 2020 dengan menggunakan pendekatan plot permanen seluas satu hektar (100 m x 100 m). KLDB merupakan bagian dari konsesi hutan tanaman industri PT Rimba Hutani Mas (PT RHM) di Provinsi Jambi. Penelitian ini bertujuan untuk mengetahui dinamika struktur dan komposisi vegetasi antara pengukuran tahun 2018 dan 2020, khususnya pada areal dengan tutupan Belukar Tua (BT). Diameter semua pohon yang telah diberi tanda nomor pada tahun 2018 diukur kembali. Pohon yang belum diberi tanda sebelumnya tetapi diameternya 10 cm setinggi dada (DBH) ditetapkan sebagai rekrutmen baru dan diberi tanda dengan nomor baru. Pengamatan dan analisis data dilakukan terhadap tiga tahap tahap pertumbuhan, yaitu tingkat pohon (10 cm DBH), tingkat pancang (10 cm DBH), dan tingkat semai (tinggi 1,5 m). Hasil penelitian menunjukkan bahwa jumlah spesies, jumlah marga, dan jumlah famili pada tingkat pohon dan pancang tinggi, sedangkan pada tingkat semai rendah. Jenis dominan pada tingkat pohon pada tahun 2018 adalah Alseodaphne bancana telah digantikan oleh Archidendron bubalinum pada tahun 2020, sedangkan pada tingkat pancang (Rothmania sp) dan tingkat semai (Aporusa microsphaera) merupakan jenis yang dominan baik pada tahun 2018 maupun pada tahun 2020. Angka kematian pada semua tahapan pertumbuhan bervariasi dengan rata-rata 4,67%. Rekrutmen di tingkat pohon 2,67% yang terdiri dari 8 spesies, 8 marga, dan 7 famili. Secara keseluruhan, semua spesies tersebar secara acak. Tinggi tajuk pohon didominasi oleh stratum C (tinggi 4 m - 20 m). Hasil pengujian hipotesis pada setiap tingkatan (pohon, pancang, semai) berbeda, namun hasil penggabungan semua data menunjukkan bahwa telah terjadi dinamika.

Impact of green initial cuttings of vegetative-active grafting points of cherry on rooting and its period, rods, and growth controlling plant substance concentration

This scientific paper presents the results of experiments on the propagation of vegetatively propagated clone grafts of cherries from green cuttings. In the experiment, the effect of the concentration of indolymic acid (IMK), the time of preparation of green cuttings and the part of the stem from which the green cuttings were obtained, on the growth of vegetatively propagated stems of cherries from green cuttings was studied. The object of study was the weakly growing vegetatively propagated VSL-2 (Krimsky-5) and CAB-6P grafts of cherries. The cuttings were treated with water concentrations of 20, 40, 60, 80, 100 mg/l to determine the optimal concentration of the growth regulating agent - IMK. Rapid acceleration of rhizogenesis processes and high root yield (78-81%) in green cuttings of cherry clone grafts were noted in the variant treated with IMK 80 mg/l water concentration. The rapid and early regeneration processes in green cuttings using the optimal concentration of IMK ensured that their conditional body diameter reached a standard (6-7 mm) size by the time of cutting grafts. In this experimental variant, the amount of plants that can be grafted has reached about 89% of the total number of plants that have taken root.

Transcriptome profiles of sturgeon lateral line electroreceptor and mechanoreceptor during regeneration

Background The electrosensory ampullary organs (AOs) and mechanosensory neuromasts (NMs) found in sturgeon and some other non-neopterygian fish or amphibians are both originated from lateral line placodes. However, these two sensory organs have characteristic morphological and physiological differences. The molecular mechanisms for the specification of AOs and NMs are not clearly understood. Results We sequenced the transcriptome for neomycin treated sturgeon AOs and NMs in the early regeneration stages, and de novo assembled a sturgeon transcriptome. By comparing the gene expression differences among untreated AOs, NMs and general epithelia (EPs), we located some specific genes for these two sensory organs. In sturgeon lateral line, the voltage-gated calcium channels and voltage-gated potassium channels were predominant calcium and potassium channel subtypes, respectively. And by correlating gene expression with the regeneration process, we predicated several candidate key transcriptional regulation related genes might be involved in AOs and NMs regeneration. Conclusions Genes with specific expression in the two lateral line sensory organs suggests their important roles in mechanoreceptor and electroreceptor formation. The candidate transcriptional regulation related genes may be important for mechano- and electro- receptor specification, in a “dosage-related” manner. These results suggested the molecular basis for specification of these two sensory organs in sturgeon.

Source of Early Regenerating Axons in Lamprey Spinal Cord Revealed by Wholemount Optical Clearing with BABB

Many studies of axon regeneration in the lamprey focus on 18 pairs of large identified reticulospinal (RS) neurons, whose regenerative abilities have been individually quantified. Their axons retract during the first 2 weeks after transection (TX), and many grow back to the site of injury by 4 weeks. However, locomotor movements begin before 4 weeks and the lesion is invaded by axons as early as 2 weeks post-TX. The origins of these early regenerating axons are unknown. Their identification could be facilitated by studies in central nervous system (CNS) wholemounts, particularly if spatial resolution and examination by confocal microscopy were not limited by light scattering. We have used benzyl alcohol/benzyl benzoate (BABB) clearing to enhance the resolution of neuronal perikarya and regenerated axons by confocal microscopy in lamprey CNS wholemounts, and to assess axon regeneration by retrograde and anterograde labeling with fluorescent dye applied to a second TX caudal or rostral to the original lesion, respectively. We found that over 50% of the early regenerating axons belonged to small neurons in the brainstem. Some propriospinal neurons located close to the TX also contributed to early regeneration. The number of early regenerating propriospinal neurons decreased with distance from the original lesion. Descending axons from the brainstem were labeled anterogradely by application of tracer to a second TX close to the spinal–medullary junction. This limited contamination of the data by regenerating spinal axons whose cell bodies are located rostral or caudal to the TX and confirmed the regeneration of many small RS axons as early as 2 weeks post-TX. Compared with the behavior of axotomized giant axons, the early regenerating axons were of small caliber and showed little retraction, probably because they resealed rapidly after injury.

A Comprehensive Ultrastructure and Transcriptome Analyses of Early Regeneration in Ophryotrocha Xiamen Sp. Nov. (Annelida: Dorvilleidae)

BackgroundIn recent years, significant progress has been made using powerful genetic approaches with newly developed models for understanding on regeneration, however, the molecular and cellular basis of early regeneration remains unclear. Annelids of the genus Ophryotrocha have long been subjects of research use as model species in ecological, toxicological, reproductive, and regenerative investigations. Although, Ophryotrocha spp., are amenable to molecular, cellular, and functional analyses, still in need to explore new model organisms in this genus to understand regeneration mechanisms. Here, we focus on a newly identified Ophryotrocha species for its early regeneration developmental mode.ResultsBased on detailed morphological (K-maxillae, rosette gland, and chromosome number) and molecular analyses, we present, O. xiamen as a new suitable model species to investigate the early regeneration mechanism. The comparative transcriptome analysis showed the gene expression patterns were related to transcriptional regulation, energy metabolism profiles and structure and signal transduction during early stages of regeneration. Data also exhibited that genes such as neurotrypsin, Nos2, DMBT1, SCO spondin, and endotubin associated to regulate inflammation, enterocyte differentiation, apoptosis, and neuroepithelial, were up-regulated during early regeneration stages (wound healing and blastema formation). Additionally, most of the known regeneration-related genes of annelids were also identified in O. xiamen which enabled to explore the precise functions of genes involved in regeneration process.ConclusionsThis study enriches the identification of genus Ophryotrocha in Chinese coastal zones, an area with high abundances of annelids. The comparative transcriptome analysis provided the whole expression changes during early regeneration process. Morphology and molecular shred of evidences in O. xiamen revealed similar features of early regeneration with other invertebrates. Information on potential candidate genes associated with early regeneration in O. xiamen, will be useful for further studies.

Establishment and Early Regeneration of Stem Cuttings from Chicken Weed (Portulaca quadrifida L.) as Influenced by Soil Types

Differences in the ability of soil are a requirement for early regeneration of a plant. It was a pot experiment carried out at Sokoto in the Sudano Sahelian agro-ecological Zone of Nigeria. The objective was to investigate the regenerative ability of stem cuttings of Chicken weed on different soil type as a strategy for the weed control. The experimental set up was 3 × 7 factorial arrangement in a Completely Randomized Design. The treatments consisted of seven stem cuttings types namely (NLA-D - node leaf attached at distal stem location, NLR-D - node leaf removed from distal stem location, NLA-P- node leaf attached at proximal stem location, NLR-P- node leaf removed from proximal stem location, IN-D - internodes at distal stem location, IN-P- internodes from proximal stem location and SRA- stem roots attached) and three soil textural class (Sandy, Silty clay and Loamy sand). Result revealed that Silty clay recorded highest number of survived plants. Plant height, number of leaves, nodes, internodes and internodes length were greatly favoured by sandy soil. Loamy sand supported the earliness to leaf emergence and flowering. NLA-D supported the early regeneration of the plant in all stem cuttings tested, but earliness to leaf emergence and flowering was better with NLAP. This finding gave information that Chicken weed regenerate profusely and control measures should be administers to save target crop from yield losses. Keywords: distal, proximal, stem cuttings, soil textural class, regeneration