Michelia maudiae ‘Rubicunda’ (M. maudiae ‘Rubicunda’) is one of the most popular ornamental plants. However, relatively little is known regarding its floral development. Here, the variations of the mineral, endogenous hormone, and non-structural carbohydrate (NSC) contents in the petals and gynoecium and androecium (GA) at five developmental stages during M. maudiae ‘Rubicunda’ flower development were analyzed. The results suggested that the carbon (C), nitrogen (N), and phosphorus (P) endogenous hormones, NSC contents, and C/N/P stoichiometric ratios exhibit large variations during flower development. There were significant differences in N and P contents in the GA and petals among the five growth stages, while C contents did not change significantly. In the five flower development stages, the average N and P contents in the GA were higher than those in the petals. The maximum C/N and N/P ratios in the GA and petals were foundat the senescent flower stage (stage5) and green bud stage (stage1), respectively. The C/P ratio in petals reached its maximum value at the mature bud stage (stage 2), and the C/P ratio in the GA reached its maximum value at the senescent flower stage (stage 5). The C/N/P stoichiometric ratios in the petals were more sensitive to development stages than those in the GA. There were highly significant correlations between the NSC and C/N/P stoichiometric ratios in the GAand petals. Moreover, acetic acid (IAA), abscisic acid (ABA), gibberellic acid 3 (GA3), and cytokinin (CTK) contents in the petals exhibited significant changes in response to development stages. Principal component analysis (PCA) revealed significant correlations and clear differences in the test indexes between the development stage and organs, and the variation was explained by PC-1 (55.6%), PC-2 (23.3%), and the cumulative contribution percentage of the total biplot (78.9%). These studies can lay the foundation for elucidating the requirements and dynamic balance among C, N, P, NSC, and hormone contents during the flower development of M. maudiae‘ Rubicunda’.

Abelmoschus manihot L. (A. manihot) has received more and more attention due to its potential edible and medicinal value. It shows higher yield and related fine agronomic traits suitable for disadvantaged areas and low-input planting. However, a systemic description of the phenological growth stages of A. manihot, an alternative, multipurpose crop of worldwide interest, does not exist. This study aims to detail the phenological growth stages of A. manihot based on the BBCH scale. Nine principal growth stages were described from seed germination to senescence, along with 69 secondary growth stages, including germination, leaf development, formation of side shoots, primary stem elongation, inflorescence emergence, flowering, fruit development, maturation of fruit and seed, and senescence. However, the morphology and structure of A. manihot become complex with growth, and some growth stages, like inflorescence development, flowering, fruit development, and fruit maturation, overlap totally or partially with each other. Thus, the three-digit scale is considered necessary for a complementary description of these growth stages and illustrations for clarification. Moreover, the unique morphology and structure features of the pistil, stamen, and ovary and the development process of fruits and seeds were described in detail at different stages. The basic and extended BBCH scales will add new information on defining and identifying A. manihot phenological growth stages. They will help farmers efficiently schedule and manage A. manihot cultivation and improve knowledge dissemination among growers and researchers.

Cercis chinensis Bunge (C. chinensis), well known as an ornamental plant widely distributed in China, and its flowers, bark, fruit, etc., have multiple bioactivities. However, reports on the changes in mineral elements, nutrient composition and antioxidant activity in C. chinensis flower at different development stages are rare. In this study, the flower samples were collected every 20 days from March 2023 to May 2023. The changes in carbon (C), nitrogen (N), phosphorous (P), soluble protein (SP), amino acid (AA), non-structural carbohydrate (NSC), total phenol (TP) and total flavonoids (TF) content as well as antioxidant activity in C. chinensis flower at different development stages were investigated. The results suggested that C, N, and P content, the C:N:P stoichiometric ratio, NSC contents, SP, AA, TP, TF and antioxidant activity of flower showed large variations at three development stages. This study found that C and P contents showed a significant decrease with the development and opening of flowers, while N content showed an opposite trend. The soluble protein content first decreased and then increased. The amino acid content, total polyphenol content, and total flavonoid content all showed a significant downward trend, while the content of NSC increased. Both ABTS and ferric-reducing antioxidant power (FRAP) showed significant decreases at various developmental stages, but DPPH was completely opposite. The highest NSC content and DPPH activity were observed at stage III, but the highest AA, TP, TF, as well ABTS and FRAP activity wereobserved at stage I. These findings will improve understanding of the requirements and dynamic balance among C, N, and P, NSC and nutrient contents as well as antioxidant activity of C. chinensis flowers in response to development stages.