No abstract

Styrax japonicus is a gorgeous species with high medicinal and ornamental values. Floral scent is an important feature of this species. However, the previous study on its floral scent is limited. To demonstrate the effects of methyl jasmonate on floral scent compounds in Styrax japonicus at different flowering stages, static headspace solid‐phase microextraction coupled with gas chromatography‐mass spectrometry was adopted. The results showed that 22 volatile compounds were identified in control at initial flowering, full flowering and end flowering stage. Besides, the relative content of these compounds increased with the development of flowers. Linalool, estragole and germacrene‐d were main volatiles. Compared to the control, 4 new compounds were determined under methyl jasmonate treatment, including β‐elemene, α‐muurolene, β‐caryophyllene and alloaromadendrene. 26 volatile compounds were found under 200 μmol/L methyl jasmonate treatment with much higher contents of α‐pinene and linalool. Meanwhile, 200 μmol/L methyl jasmonate enhanced the relative content of volatile compounds at three flowering stages. This treatment also contributed to the highest content of linalool, followed by control. The linalool content displayed a continuous increasement in both 200 μmol/L methyl jasmonate treatment and control. Our research highlighted that the application of methyl jasmonate, especially with the concentration of 200 μmol/L, had a more positive impact on the type and the relative content of volatile compounds in S japonicus flowers. The results helped to understand the release patterns of volatile compounds in S japonicus flowers and provide important information to regulate the floral scents.

Styrax is a gorgeous species combined with high medicinal and ornamental values, however, information about its floral scents is limited. This study aimed to reveal the floral scent compounds and the dynamic changes in the flowering process of Styrax japonicus, S. grandiflora and S. calvescens. Static headspace solid-phase microextraction coupled with gas chromatography-mass spectrometry was adopted in the present study. The results showed that 24, 22 and 22 volatile compounds were present at three flowering stages, among which linalool, ocimene, α-pinene and germacrene D dominated in different species. Terpenes were the main floral scent compounds in all species, whereas there was considerable relative content of ketones in S. japonicus. Among the major terpenes, α-pinene, ocimene and myrcene were the common volatiles in these species, while β-elemene and allo-ocimene were the specific volatiles in S. japonicus and S. calvescens, respectively. The highest content of terpenes occurred at initial flowering stage in three species. The differences in the type and content of principal compounds contributed to the fragrance diversity among these species. A solid foundation for understanding the complexity of volatile emission could be obtained from our findings, meanwhile, effective utilization of abundant terpenes in flowers of Styrax species should be applied.

Styrax japonicus is a small ornamental tree with medicinal values, although its flowering period is short. To date, information about the morphological and physiological characteristics of the petals during the flowering period is limited. In this study, we observed the structure of the petals at the full flowering stage with a scanning electron microscope and detected the contents of nutrients, minerals, and endogenous hormones and the activities of enzymes at different flowering stages. The results showed that the content of soluble sugar exhibited an ‘increase-decrease’ trend, whereas the contents of soluble protein, nitrogen (N), phosphorus (P), and abscisic acid (ABA) showed a ‘decrease-increase’ pattern. The content of starch descended continuously, but the contents of potassium (K), gibberellic acid (GA3), indoleacetic acid (IAA), and malondialdehyde (MDA) ascended continuously. The activities of peroxidase (POD) and superoxide dismutase (SOD) first rose and then declined during the flowering period. Higher contents of soluble sugar, N, K, and IAA promoted S. japonicus flowering; meanwhile, lower contents of starch, soluble protein, P, and GA3 in addition to the lower activity of SOD might be some of the causes of the short flowering period. This work will serve as the foundation for a scientific technique to utilize the flowers and extend the flowering period in S. japonicus.

Background: The conventional fertilization regime ignores the allometric characteristics of Quercus nuttallii seedlings, challenging them to meet the nutritional needs at each growth stage. This study was conducted to determine the impact of exponential fertilization on the growth and nutrient status of Q. nuttallii container seedlings. Methods: Two fertilization regimes (average/exponential) were performed on Q. nuttallii container seedlings, and varied gradients (0, 300, 500, 700, and 900 mg/seedling) of N supply were set for the two regimes. Result: N application promoted the seedling height, root collar diameter, total biomass, and N/P/K accumulation of Q. nuttallii, and the exponential fertilization obtained better effects in general. An appropriate amount of exponentially N application was beneficial to the growth of root system, whereas excessive dosages inhibited it. Judging from seedlings growth status and nutrient accumulation, 900 mg/seedling under exponential fertilization was adequate for Q. nuttallii seedlings. However, 500 and 700 mg/seedling under exponential fertilization may have advantages in improving seedlings’ stress resistance. Conclusions: Exponential fertilization did not only meet the nutrient requirements and promote the growth of Q. nuttallii seedlings, but also facilitated the root growth to indirectly accelerate the assimilation of N/P/K, therefore improving the afforestation quality.