Original Paper Horticultural Science (Prague), 48, 2021 (3): 126–133 https://doi.org/10.17221/28/2020-HORTSCI Generative propagation and fertilisation of Stipeae species – wild grasses with ornamental potential Anna Kapczyńska1*, Bożena Stodolak2 1Department of Ornamental Plants and Garden Art, Faculty of Biotechnology and Horticulture, University of Agriculture in Krakow, Poland 2Department of Biotechnology and General Technology of Food, Faculty of Food Technology, University of Agriculture in Krakow, Poland *Corresponding author: [email protected] Citation: Kapczyńska A., Stodolak B. (2021): Generative propagation and fertilisation of Stipeae species – wild grasses with ornamental potential. Hort. Sci. (Prague), 48: 126–133. Abstract: The wild grasses are of increasing interest among landscape architects. The appropriate plant selection is crucial for the subsequent survival and growth of plants in grassy gardens. The aim of the experiment was to assess the influence of seed age (1–3-year old seeds) on the germination of three Stipeae species: Eriocoma occidentalis subsp. californica, Stipa pulcherrima and Hesperostipa curtiseta. The seed weight and germination percentage showed a decline over a period of seed storage. There was 31–84% (depending on species) loss in germinabil- ity of 3-year old seeds in comparison to 1-year old seeds. After germination, plants were repotted and treated with Osmocote (a slow-release fertiliser, N15 + P10 + K12). The results indicated that fertilisation significantly increased the number of roots, stems, leaf length, leaf dry weight, chlorophylls and proline content. None of the tested species flowered in the year of sowing but in the next growing season. Plants fertilised in the previous year formed more and of better quality inflorescence stems. Keywords: Poaceae; wild species; Eriocoma; Hesperostipa; Stipa In recent years, landscape architects are open moving with every breeze bring sound and move- to unknown perennials offering interesting and ment to gardens and larger landscapes. Eriocoma oc- close to natural alternatives to well-known and cidentalis subsp. californica (formerly Stipa califor- popular high-coloured plants. The tested species nica), Stipa pulcherrima and Hesperostipa curtiseta represent wild flora, which enriches the dry grass- (formerly Stipa curtiseta) are of ornamental poten- lands and steppe vegetation. Introducing them tial. They represent three little-known taxa within to the human environment, we increase biodiver- Stipeae tribe (Gould et al. 2013; Peterson et al. 2019) sity and create mini landscapes that resemble wild which propagation has not been described. Tra- nature. The tribe Stipeae belongs to the subfamily ditional vegetative propagation of grasses is more Pooideae in Poaceae family and includes 527 spe- often used in horticultural practice than generative cies which distribute mostly on dry open grasslands method (Kapczyńska et al. 2020) as in many cases and steppe vegetations all over the world (Jacobs et uniform and true to type offspring can be obtain al. 2007; Peterson et al. 2019). Most Stipeae species only through asexual propagation. However, it is are distinct for their characteristically clump shape important to start testing the reproduction of little- formed of basal foliage from which upright inflores- known taxa with natural methods, i.e. using seeds cence stems (enriched by long awns) arise in early – this method is very efficient and doesn’t require to mid summer. Their lissome leaves and flowers expensive propagation structures. Germination rate 126 Horticultural Science (Prague), 48, 2021 (3): 126–133 Original Paper https://doi.org/10.17221/28/2020-HORTSCI is usually different with the different grass species and keep watered. Daily average temperature inside (Jiao et al. 2009) and there is no universal scheme the greenhouse, minimum and maximum tempera- of proceeding as it is regulated by complex interac- ture as well as radiation from June 2015 to July 2016 tions between endogenous factors and exogenous are presented in Figure 1. The appearance of the environmental conditions (Lamichhane et al. 2018; first leaf was used as the criterion for germination. Zhou et al. 2020) – therefore it should be developed The number of seeds germinated was counted and and tested separately for each individual genotype. the germination percentage was determined. Seed- The presented results first implement the biologi- lings emerged were systematically counted to cal- cal progress which in horticultural production can culate Piepper’s index (WPiep), which determines be facilitated by introducing new or less-well-known the average time (days number) of germination of a plant species to cultivation, ones that feature orna- single seed (Pipper 1952). mental qualities and may have a broad range of uses. Second, expand the ornamental grasses palette WPiep = s1d1+s2d2+...+sndn/s1+s2+...+sn for a new wave of naturalistic landscape design and where: to propose drought-tolerant grass species that could s – number of germinated seeds in subsequent days be adapted in the future to a wide range of urban and of observation; suburban difficult climatic conditions. Third, -pro d – number of days from seeds sowing. mote the endangered grasslands species eg. Stipa pulcherrima (Novák, Prach 2010) in order to pre- On 10th July 2015, to explore the effects of fertilisa- serve biodiversity in the human environment. Final- tion on the growth and quality of Stipeae species, seed- ly, expand knowledge about the tribe Stipeae and its lings obtained from one-year-old seeds (16–18 cm species in terms of propagation, cultivation and plant high) were transplanted individually in standard morphology, flowering process and crop potential. round plastic pots (12 cm in diameter, 0.6 liter) filled The objective of this study was to determine the ef- with the peat substrate (Botanica Professional Com- fects of seed age on the germination process and eco). The substrate has: N (N-NO3) – 112 mg/L, of fertilisation on the growth and flowering of the P – 36 mg/L, K – 282 mg/L, Ca – 1 174 mg/L, Mg – three ornamental grasses. 110 mg/L, Cl – 35 mg/L and the pH is 6.26. The sub- strate was supplied with a slow release fertiliser MATERIAL AND METHODS (Osmocote Plus with 5–6 months action 15N + 10P + 12K + 2MgO + microelements, Scotts Company), 5 g The experiment was conducted in a greenhouse per each pot (fertilised plants – FERT). The control (seed germination) and on the experimental plot plants (CTRL) were planted in the substrate without (fertilisation study) at the Faculty of Biotechnology fertiliser. The experiment was carried out with four and Horticulture University of Agriculture in Kra- replications, each treatment consisting of 20 plants kow, Poland (lat. 50.08°N, long. 19.95°E, elevation (4 × 5 plants). For proper rooting, plants were cultivat- 219 m) in 2015 and 2016. The seeds of Eriocoma oc- ed in a greenhouse until 31st July 2015, then the pots cidentalis subsp. californica (Merr. & Burtt Davy) with plants were moved to the open field conditions Romasch., Stipa pulcherrima K. Koch and Hes- (experimental plot) and keep watered (monthly field perostipa curtiseta (A.S. Hitchc.) Barkworth were re- 24 h average, lowest and highest temperature as well ceived from the Plant Breeding and Acclimatization as radiation from August 2015 to June 2016 are pre- Institute in Bydgoszcz (Poland). The seeds were har- sented in Figure 1). On 7th September 2015 the plants vested in 2012, 2013 and 2014, so at the time of the were evaluated. Data were collected including on experiment, they were three, two and one year old, the number of roots per plant, the average length respectively. After harvest, the seeds were dry stored of roots, the number of vegetative stems per plant, at room temperature. Before sowing, the weight (g) the average length of leaves. At the same time the leaf of 10 seeds was determined separately for each spe- dry weight (DW), chlorophylls (Chl a, Chl b, Chl a+b) cies harvested in the different years. On 9 June 2015, and proline content in leaves were estimated. the seeds (4 × 30 seeds in each object) were sown In the first growing season after sowing in 2015 singly in cell seedling trays (one cell 62 mm) filled none of Stipeae species flowered. To be able to as- with a peat substrate (Botanica Professional Com- sess the effect of fertilisation applied in 2015 on eco, Poland). The trays were placed in a greenhouse the flowering of plants in the following year in 2016, 127 Original Paper Horticultural Science (Prague), 48, 2021 (3): 126–133 https://doi.org/10.17221/28/2020-HORTSCI 50 RAD AT HT LT 40 ° 30 20 10 0 –10 Figure 1. 24h average (A), lowest (L), highest (H) temperatures (T) and radiation (RAD) during the experiment the pots with plants (controlled and fertilised) were hydrin + 30 mL glacial acetic acid + 20 mL of 2 M buried in the ground in October 2015 to overwin- orthophosphoric acid) and incubated in a boiling ter in field condition. The pots were buried to a water bath for 1 hour. After cooling, 2 ml of tolu- level equal to the upper edge of the pot (to a depth ene was added and the sample was vortexed and left of 9 cm). On 17th May 2016, the survival (%) of grass- to phase separation. The absorbance of the toluene es was evaluated. Additionally, the date of the be- phase was measured at 520 nm. The proline con- ginning of flowering (when the first inflorescence on centration in the sample was determined using a the plant was visible), inflorescence stems per plant standard curve (0–10 μg/mL) and expressed as μg/g (no), inflorescence stem length (cm) and inflores- of fresh weight. Three analytical replications for pro- cence length (cm) were investigated. line content were performed for each treatment. Determination of chlorophyll content. Chloro- Statistical Analysis. All data were analysed using phylls content was determined spectrophotometri- Statistica 10.0 data analysis software system (StatSoft, cally (Spekol 1500, Analytik Jena, Germany) and Tulsa, USA).