No abstract

Guttation is the process of exudating droplets from the tips, edges, and adaxial and abaxial surfaces of the undamaged leaves. Guttation is a natural and spontaneous biological phenomenon that occurs in a wide variety of plants. Despite its generally positive effect on plant growth, many aspects of this cryptic process are unknown. In this study, the guttation phenomenon characteristic of bamboo shoots and the anatomical feature of these and culm sheaths were systematically observed. In addition, the water transport pathway and the compounds in guttation droplets of bamboo shoots were analyzed, and the effect of bamboo sheaths’ guttation on the growth of bamboo shoots was assessed. The results revealed that bamboo shoots began to exudate liquid in the evening through to the next morning, during which period the volume of guttation liquid gradually increases and then decreases before sunrise. Many vascular bundles are in bamboo shoots and culm sheaths to facilitate this water transport. The exudate liquid contains organic acids, sugars, and hormones, among other compounds. Our findings suggest that the regular guttation of the sheath blade is crucial to maintain the normal growth of bamboo shoots.

Roots are essential for plant growth and development. Bamboo is a large Poaceae perennial with 1,642 species worldwide. However, little is known about the transcriptional atlas that underpin root cell-type differentiation. Here, we set up a modified protocol for protoplast preparation and reported single-cell transcriptomes of 14,279 filtered single cells derived from the basal root tips of Moso bamboo. We identified four cell types and defined new cell type-specific marker genes for the basal root. We reconstructed the developmental trajectories of the root cap, epidermis, and ground tissues and elucidated critical factors regulating cell fate determination. According to in situ hybridization and pseudotime trajectory analysis, the root cap and epidermis originated from a common initial cell lineage, revealing the particularity of bamboo basal root development. We further identified key regulatory factors for these cells differentiation and indicated divergent root developmental pathways between Moso bamboo and rice. Additionally, PheWOX13a and PheWOX13b ectopically expressed in Arabidopsis inhibited primary root and lateral root growth and regulated the growth and development of root cap, which was different from WOX13 orthologs in Arabidopsis. Taken together, our results offer an important resource for investigating the mechanism of root cell differentiation and root system architecture in perennial woody species of Bambusoideae.

No abstract

Exploring the mechanism of Gibberellic acid (GA 3 ) treatment on seed germination of moso bamboo can lay a foundation for its future breeding and research. In this study, the germination-related indicators (germination rate, germination potential, vigor index, respiration rate) with different content of GA 3 treatment were measured, and the ultrastructure of moso bamboo seeds treated with low and high GA 3 concentrations was observed during the germination process. In addition, the transcriptome data of the germination seeds, with and without GA 3 treatment were analyzed. The results showed that the low GA 3 concentration (10 mol/L) increased the germination rate, germination potential, vigor index and respiration rate, thus promoting the germination of moso bamboo seeds, but a high concentration of GA 3 (50 mol/L) inhibited the seed germination. The low GA 3 concentration accelerated the decomposition of starch and fat and promoted the vacuole formation of cells, but the high GA 3 concentration damaged organelles and increased the endocytosis of cells. Compared with untreated moso bamboo seeds, the seeds had fewer genes expressed after GA 3 treatment. Starch and carbon metabolism play a very important role in seed development and embryo viability, whether the seed is treated with GA 3 or not. After hormone treatment, GID1 and DELLA-related genes homologous to rice genes is not expressed, but the expression of PIF4, PIF5, GA 3 ox 2, GA 2 oxs , etc., were up-regulated.