Impatiens balsamina is an annual herb, cultivated as a valued medicinal and ornamental plant all over China. It is also used as a popular dye, and in some places it is referred to as “henna.” For centuries, the aboveground parts of this plant have been used in traditional Chinese medicine for their antimicrobial, antirheumatic, antipruritic, anti-inflammatory, antiallergic, and antitumoral properties, and for the treatment of difficult labor and puerperal pain (Kang et al., 2013; Shin et al., 2015). Many active ingredients have been isolated from I. balsamina, including phenolics, flavanols, anthocyanin pigments, and saponins (Oku and Ishiguro, 2002; Yang et al., 2001). Although metabolites from this plant have been extensively studied (Chua, 2016; Kang et al., 2013; Sakunphueak et al., 2013; Su et al., 2012), reports of detailed studies on anther development, cytological features, and distribution of nutritional reserves in the anthers of I. balsamina are scarce.
The flower, as an important reproductive organ, is believed to be a very complicated part of angiosperms. Specifically, the floral differentiation process and significant structural changes are complex mechanisms. Male reproductive development in higher plants is an intricate biological process that includes the formation of anthers with differentiated tissues, in which microspores and pollen are formed. As the anther morphology becomes established, the anther typically consists of microsporocytes at the center of each anther locule surrounded by four different cell layers: the epidermis, the endothecium, the middle layer, and the tapetum from the outer to the inner. The successful development of pollen grains within the anther requires active cooperation and interaction between the sporophytic and gametophytic molecules (Zhang et al., 2010).
Cell inclusions, especially calcium oxalate crystals are secondary metabolites and biominerals in plants, and are distributed among all taxonomic levels of angiosperms. Calcium oxalate crystals occur in five morphologically different forms, one or more of which are found in most angiosperm families (Franceschi and Horner, 1980; Franceschi and Nakata, 2005). Knowledge of plant crystals consists almost entirely of details of crystal structure, how the crystal forms within the cell, and distribution of crystals in mature organs. Crystal types, their specific distribution, and development are neglected aspects of crystallization. Many plants accumulate crystals of calcium oxalate, but how these crystals form remains unknown (Nakata, 2012, 2015). Since then, crystals of calcium and oxalate have been reported in more than 215 plant families (McNair, 1932).
In this study, the ultrastructure and histochemical changes associated with the various developmental stages of anthers were investigated, with a focus on changes of polysaccharides and lipids, which are nutritional materials. Study on the synthesis and distribution of nutritional constituents in the anthers can provide understanding viability and its role in reproductive fitness. In addition, the features of calcium oxalate crystals in the anthers, representing a nonmolecular synapomorphy were examined to gain insights into the reproductive biology and evolution of I. balsamina.
Casselman, W.G.B. 1954 Acetylated Sudan Black B as a more specific histochemical reagent for lipides Qrtly. J. Microscopicalence 95 321 322
Chua, L.S. 2016 Untargeted MS-based small metabolite identification from the plant leaves and stems of Impatiens balsamina Plant Physiol. Biochem. 106 16 22
Dahlqvist, A., Olsson, I. & Nordén, A. 1965 The periodate-Schiff reaction: Specificity, kinetics, and reaction products with pure substrates J. Histochem. Cytochem. 13 423 430
Hu, S.Y. 1990 A cytochemical technique for demonstration sections of lipid drops, starch and protein bodies in thick resin sections Acta Bot. Sin. 32 841 846
Kang, S.N., Goo, Y.M., Yang, M.R., Ibrahim, R.I., Cho, J.H., Kim, I.S. & Lee, O.H. 2013 Antioxidant and antimicrobial activities of ethanol extract from the stem and leaf of Impatiens balsamina L. (Balsaminaceae) at different harvest times Molecules 18 6356 6365
Lersten, N.R. & Horner, H.T. 2005 Development of the calcium oxalate crystal macropattern in pomegranate (Punica granatum, Punicaceae) Amer. J. Bot. 92 1935 1941
Liu, C.W., Cong, K.M., Cai, Y.Y. & Zhen, X. 2006 Characteristics of calcium oxalate crystals of several species in Impatiens and their taxonomic significance Life Sci. Res. 10 328 332
McNair, J.B. 1932 The interrelation between substances in plants: Essential oils and resins, cyanogen and oxalate Amer. J. Bot. 19 255 271
Nakata, P.A. 2015 An assessment of engineered calcium oxalate crystal formation on plant growth and development as a step toward evaluating its use to enhance plant defense PLoS One 10 e0141982
Sakunphueak, A., Tansakul, P., Umehara, K., Noguchi, H. & Panichayupakaranant, P. 2013 Effect of methionine on production of naphthoquinones in Impatiens balsamina root cultures and detection of some secondary metabolites Pharm. Biol. 51 36 41
Shin, J.A., Ryu, M.H., Kwon, K.H., Choi, B. & Cho, S.D. 2015 Down-regulation of Akt by methanol extracts of Impatiens balsamina L. promotes apoptosis in human oral squamous cell carcinoma cell lines J. Oral Pathol. Med. 44 420 428
Su, B.L., Zeng, R., Chen, J.Y., Chen, C.Y., Guo, J.H. & Huang, C.G. 2012 Antioxidant and antimicrobial properties of various solvent extracts from Impatiens balsamina L. stems J. Food Sci. 77 C614 C619
Yang, S.J., Cheng, C., Song, T.D. & Tian, H.Q. 2013a The character of anther development of Impatiens balsamina Subtrop. Plant Sci. 42 283 287
Yang, S.J., Wei, D.M., Cheng, C., Song, T.D. & Tian, H.Q. 2013b Histochemical study of polysaccharides and lips on the developing anther of I. balsamina Acta Botanica Boreal-Occident Sinica 33 1786 1791
Yang, X., Summerhurst, D.K., Koval, S.F., Ficker, C., Smith, M.L. & Bernards, M.A. 2001 Isolation of an antimicrobial compound from Impatiens balsamina L. using bioassay-guided fractionation Phytother. Res. 15 676 680
Zhang, D., Liang, W., Yin, C., Zong, J., Gu, F. & Zhang, D. 2010 OsC6, encoding a lipid transfer protein, is required for postmeiotic anther development in rice Plant Physiol. 154 149 162