What's to know about hibiscus

1. The introduction of Roselle

Roselle (Hibiscus sabdariffa L.) also known as Hibiscus is an annual herbaceous plant in the genus Hibiscus of the mallow family. Roselle is a tetraploid plant (2n=4x=72) that originated in Africa.Introduced into Taiwan in 1910, it has been cultivated in a large area in Guangxi, Fujian, Guangdong, Yunnan and other places in China, and is a tropical and subtropical cash crop with a variety of economic uses.

2. The biological characteristics of Hibiscus

Hibiscus is a dicotyledon plant with conical straight root system, and the stem color is divided into four types: red (Figure 1a), green (Figure 1b), purple red (Figure 1c), and red-green mosaic (Figure 1d). 

The leaves are palmate lobes, which change according to certain rules, and the leaf cycle is presented as ovate leaves-trilobed-pentalobed-trilobed-trilobed-lanceolate (Fig. 2); 

The flower color was divided into three types: yellow (Fig. 3a, B), pink (Fig. 3c), and purple red (Fig. 3d). The corolla is detached and spiral-shaped, with 5 petals, superimposed, born alone in leaf axils, and the peduncles are short; The anthers are yellow, yellow-brown, dark brown 3 kinds, bean-shaped, each flower about 60 anthers; There are two colors of stigma: purple and yellow; 

The calyx of rosette (Fig. 4) is fleshy, with 5-7 sepals, triangular, tapering, and inferior synphytic; 10-14 parasepals, attached to the base of the sepals; The sepals have a pronounced midrib, forming a pronounced ridge along the edge of the sepals, and on the back of the sepals there is a pronounced gland, the calyx gland (Figure 5a), which begins to secrete nectar on the day of flowering; 

Roselle capsules are ovoid, with a hairy surface (Figure 5b), 5-6 chambers per fruit, 4-6 seeds per chamber; Seeds are yellowish brown or grey-brown when mature, seeds sub-kidney shaped (Figure 5C), 1,000 grains weighing 30-40 g; The seed has a large embryo, with a bead hole at the tip, the seed umbilicus is diamond-shaped, the ovule is inverted, and there is a ridge-like band near the bead hole and the seed umbilicus, containing a vascular bundle, and the bead stem is curved called the seed vein.

Fig. 1 Morphological characteristics of Roselle stems

Fig. 2 Morphological characteristics of Roselle leaves

Fig. 3 Morphological characteristics of Roselle flowers

Fig. 4 Morphological characteristics of Roselle calyx

Fig. 5 Morphological characteristics of Roselle capsules, seeds and calyx glands

References

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3. Shahidi F, Ho C T. Phenolic compounds in foods and natural health products. Oxford University Press, 2005. 114-142.

4 . ZENG Tinghua, XU Xiong, ZHUO Rensong Chemical composition and utilization of Roselleum (review). Subtropical Plant Communications, 1980, 1:8-18

5. CHEN Muzhi, LIU Dongfeng, ZHUANG Biao , LIN Fuzhen Development and research of Roselle seed oil China Oils and Fats, 2001, 5:10-1

6. Jin Jianliang. Cultivation of "Red Peach K" Technique . Sichuan Agricultural Science and Technology, 2007, 11:35

7. Li Huizhong High-yield cultivation technology of Roselle set corn Yunnan Agriculture, 2011, 7: 13

8 . LI Xiufen, ZHU Jianjun, ZHANG Jianfeng, YIN Liqing Research Progress on Introduction and Application of Hibiscus Tomato Shanghai Journal of Agricultural Sciences, 2015, 31(5):136-139

9. Lin Dongsheng A preliminary study on the plantation of Roselleae in rubber plantations Fujian Rezuo Science and Technology, 1990, 2: 33-34

10. Lu Dewen Effects of phosphorus stress on physiological and biochemical effects of Hibiscus seedlings Anhui Agricultural Science Bulletin, 2012, 18(21): 83-86

11. Yanhong Zhao, Wenhuan Hou, Xiaofang Liao, Xingfu Tang , Chuying Li Effects of different sunshine duration on the main agronomic traits of Roselleum Crops, 2020, 2: 172-175