Feng Chen

The GRF (Growth-Regulating Factor) gene family has indispensable regulatory functions in the morphological and physiological development of plants. Nonetheless, comprehensive investigations of GRF gene family members and their functional roles in Cymbidium goeringii, Cymbidium ensifolium, and Cymbidium sinense are still lacking. Therefore, the GRF gene family members in three Cymbidium species were systematically identified, and their expression profiles and potential biological functions were comprehensively evaluated in the study. The results provided evidence that eleven, eleven, and nine GRF genes were identified in C. goeringii, C. ensifolium, and C. sinense, respectively. These genes encode proteins considered as 153–584 amino acids and have been postulated to be located in the cell nucleus. The promoter contains cis-acting elements associated with hormone response regulation, tissue-specific expression, modulation of organismal growth and development, and environmental signal response. The analyses of gene architecture and motif composition demonstrated that introns and motifs within each evolutionary branch are highly similar, whereas significant differences exist between evolutionary branches. The results of chromosome localization and collinearity analysis showed that only a pair of segmental duplication genes was identified in C. goeringii. Moreover, transcriptome data and qRT-PCR results indicated that GRF genes are involved in various organs of C. goeringii. In conclusion, these findings may establish a foundation for theoretical inquiry into the future functional analysis of GRF genes in orchids.

Phalaenopsis is a widely cultivated ornamental plant of considerable economic value worldwide. However, traditional growing medium, sphagnum moss, is limited and non-renewable. It also decomposes slowly and is prone to environmental issues. Therefore, there is an urgent need to identify more environmentally friendly and efficient alternatives. Biochar, a sustainable material with excellent physical and chemical properties, has been recognized as an effective promoter of plant growth. In this study, we investigated the influence of biochar derived from three raw materials (corn straw, bamboo, and walnut) mixed1 with coconut shell at ratios of 1:2, 1:10, and 4:1, on the growth of Phalaenopsis ‘Big Chili’. Over a 150-day controlled experiment, we evaluated multiple growth parameters, including plant height, crown width, total root length, total projected area, total surface area, and root volume. Compared to the traditional growing medium, the optimal biochar-coconut shell mixture (maize straw biochar: coconut shell = 1:2) increased plant height and crown width by 7.55% and 6.68%, respectively. Root metrics improved substantially, with total root length increasing by 10.96%, total projected area by 22.82%, total surface area by 22.14%, and root volume by 38.49%. Root biomass in the optimal treatment group increased by 42.47%, while aboveground and belowground dry weights increased by 6.16% and 77.11%, respectively. These improvements were closely associated with favorable substrate characteristics, including low bulk density, high total and water-holding porosity, moderate aeration, and adequate nutrient availability. These findings demonstrate that substrate characteristics critically influence plant performance and that biochar–coconut shell mixtures, particularly at a 1:2 ratio, represent a viable and sustainable alternative to sphagnum moss for commercial cultivation of Phalaenopsis.