Calmodulin-binding transcription factor (CAMTA) is an important component of plant hormone signal transduction, development, and drought resistance. Based on previous transcriptome data, drought resistance genes of the Heimia myrtifolia CAMTA transcription factor family were predicted in this study. The physicochemical characteristics of amino acids, subcellular localization, transmembrane structure, GO enrichment, and expression patterns were also examined. The results revealed that H. myrtifolia has a total of ten members (HmCAMTA1~10). Phylogenetic tree analysis of the HmCAMTA gene family revealed four different branches. The amino acid composition of CAMTA from H. myrtifolia and Punica granatum was quite similar. In addition, qRT-PCR data showed that the expression levels of HmCAMTA1, HmCAMTA2, and HmCAMTA10 genes increased with the deepening of drought, and the peak values appeared in the T4 treatment. Therefore, it is speculated that the above four genes are involved in the response of H. myrtifolia to drought stress. Additionally, HmCAMTA gene expression was shown to be more abundant in roots and leaves than in other tissues according to tissue-specific expression patterns. This study can be used to learn more about the function of CAMTA family genes and the drought tolerance response mechanism in H. myrtifolia.

Lagerstroemia indica is a widely used ornamental plant in summer gardens because of its desirable plant shape. The weeping traits of plants are related to secondary cell wall thickness and hormone signaling. NAC (NAM-ATAF1/2-CUC2), as one of the plant-specific transcription factors, is a switch for the secondary cell wall and also involved in leaf senescence, phytohormone signaling, and other growth processes. We identified a total of 21 LiNAC genes from the transcriptome data, which we divided into 14 subgroups and 2 groups. The physicochemical characteristics of amino acids, subcellular localization, transmembrane structure, GO and KEGG enrichment, and expression patterns were also examined. The qRT-PCR analysis showed that the expressions of LiNAC8 and LiNAC13 in upright L. indica ‘Shaoguifei’ and weeping L. indica ‘Xiariwuniang’ were significantly higher from the beginning to the end of growth stage (S1–S3), and the expressions of ‘Shaoguifei’ were always higher than those of ‘Xiariwuniang’. However, LiNAC2 showed a downward trend in S1–S3 and the relative expression level of ‘Shaoguifei’ was lower than that of ‘Xiariwuniang’. It is hypothesized that these LiNAC genes may be involved in the regulation of weeping traits in L. indica. The results of this study provide a basis for analyzing the functions of LiNAC genes and help to explore the molecular regulatory mechanisms related to the weeping traits in L. indica.

Flower bud differentiation is a key component of plant blooming biology and understanding how it works is vital for flowering regulation and plant genetic breeding, increasing the number and quality of flowering. Red soil is the most widely covered soil type in the world, and it is also the most suitable soil type for crape myrtle planting. The flower buds of crape myrtle (Lagerstroemia indica) planted in red soil were employed as experimental materials in this study, and the distinct periods of differentiation were identified using stereomicroscopy and paraffin sectioning. We optimized the steps of dehydration, transparency, embedding, sectioning and staining when employing paraffin sections. When seen under a microscope, this optimization can make the cell structure of paraffin sections obvious, the tissue structure complete, and the staining clear and natural. The flower bud differentiation process is divided into 7 periods based on anatomical observations of the external morphology and internal structure during flower bud differentiation: undifferentiated period, start of differentiation period, inflorescence differentiation period, calyx differentiation period, petal differentiation period, stamen differentiation period, and pistil differentiation period. The differentiation time is concentrated from the end of May to mid-June. Crape myrtle flower bud differentiation is a complicated process, and the specific regulatory mechanism and affecting elements need to be investigated further.