Drought tolerance of Liriope graminifolia (L.) Baker and Ophiopogon japonicus (Thunb.) Ker Gawl. – promising lawn-forming plants for the subtropical zone of the Black Sea coast of Russia

The lawn coverings creation in the humid subtropics zone of Russia is one of the topical areas of ornamental horticulture. This is due to the high requirements for year-round decorative plantings, the peculiarities of natural and climatic conditions and the general lack of issue knowledge. This direction is of particular importance in plantations located in shaded areas under the canopy of tree crowns, where, in addition to common for the region unfavourable factors of the hydrothermal regime, insufficient illumination is added, which together limits the possibility of traditional cereal grasses cultivating. Evergreen grass-like ground cover plants can be a complete substitute for lawn grasses in shaded areas. The aim of the research was to determine the degree of drought resistance of Liriope graminifolia (L.) Baker and Ophiopogon japonicus (Thunb.) Ker Gawl. and the ability to maintain decorativeness during the period of unfavourable hydrothermal conditions in the summer in the humid subtropics of Russia. The studies were carried out in 2013-2018 on the Black Sea coast of the Caucasus in the Sochi region, in plantations (on test plots with an area of 5-10 m²) and in conditions of vegetation experiments (in containers with a volume of 2 liters) on the territory of the Kuban Subtropical Botanical Garden (settlement Uch-Dere), according to generally accepted methods adapted to the studied taxa. It was found that an important mechanism of adaptation of the studied plants to drought is the ability to accumulate and redistribute moisture between vegetative organs, providing a high water content in the leaves. The decorativeness of O. japonicus and L. graminifolia in open ground in the atmospheric moisture absence lasts up to 12-14 days, in a vegetation experiment (container culture) – up to 14-16 days. O. japonicus and L. graminifolia retained the ability to self-regenerate up to 35-37 days of the experiment, and then the plants died. The consequences of summer drought in the studied plants were compensated by active autumn growth. Unlike classic lawns, which require daily watering, lawns from O. japonicus and L. graminifolia should be irrigated with a long (more than 12-14 days) absence of precipitation in the summer months.

1. Ignatieva M., Haase D., Dushkova D., Haase A. Lawns in cities: from a globalised urban green space phenomenon to sustainable nature-based solutions, Land. 2020;9(3):73. doi:10.3390/land9030073

2. Tyuldikov V. A., Kobozev I. V., Parakhin N. V. Law science and gardening of populated areas: monograph. Moscow: Kolos, 2002, 264 p. (In Russ.)

3. Karpun Yu. N. Subtropical fl oriculture in Russia. Saint Petersburg: Publishing house “VVM”, 2012, 200 p. (In Russ.)

4. Kelina A. V., Klemeshova K. V. The most common lawn problems in the humid subtropical zone. Subtropicheskoye i dekorativnoye sadovodstvo. 2014;50:13-20. (In Russ.)

5. Ryndin A. V., Kelina A. V., Karpun N. N., Klemeshova K. V., Zhuravleva E. N. State and peculiarities of the care of lawn coverings in the humid subtropics of Russia, Kormoproizvodstvo. 2016;7:11-16. (In Russ.)

6. Grechushkina-Sukhorukova L. A. Ecological situation and peculiarities of growing lawns in the steppe zone of Russia. Yug Rossii: Ekologiya, razvitiye. 2010:23-32. (In Russ.)

7. Henkel P. A. Physiology of heat and drought resistance of plants. Moscow: Nauka, 1982, 280 p. (In Russ.)

8. Maksimov N. A. Selected works on drought resistance and winter hardiness of plants. Moscow: Izd-vo AN SSSR, 1952, Vol. 1, 575 p. (In Russ.)

9. Yang F., Ignatieva M., Larsson A., Zhang S., Ni N. Public perceptions and preferences regarding laws and their alternatives in China: A case study of Xi’an. Urban Forestry & Urban Greening. Volume 46, December 2019, 126478 https://doi.org/10.1016/j.ufug.2019.126478

10. Fantz P. R. Names and species of Ophiopogon cultivated in the Southeastern United States, Hort Technology. 2009;19(2):385-394.

11. Nesom G. L. Overview of Liriope and Ophiopogon (Ruscaceae) naturalized and commonly cultivated in the USA, Phytoneuron. 2010;56:1-31.

12. Konnov N. A. Prospects for expanding the culturing range of representatives of the genera Liriope Lour. and Ophiopogon Ker. Gawl. outside the subtropical zone of Russia, Subtropicheskoye i dekorativnoye sadovodstvo. 2018;67:58-63. (In Russ.)

13. Konnov N. A. Ophiopogon and Liriope. Promising lawn plants, Tsvetovodstvo. 2014;6:12-14. (In Russ.)

14. Karpun Yu. N., Konnov N. A., Kuvaitsev M. V. Lawn in the shade. History, problems, recommendations. Sochi: SBSK, 2015, 28 p. (In Russ.)

15. Mosiyash A. C., Lugavtsov A. N. Agroclimatic characteristics of Greater Sochi. Rostov-on-Don: Gidrometeoizdat, 1967, 247 p. (In Russ.)

16. Karpun Yu.N. The nature of Sochi. Relief, climate, vegetation. Sochi, 2011, 20 p. (In Russ.)

17. Chen X., Liang S., Xu J., Tamura M. N. Liliaceae In Wu, Z. Y. & P. H. Raven, eds. Flora of China. (Flagellariaceae through Marantaceae) [Electronic resource]. Beijing: Science Press and St. Louis: Missouri Botanical Garden Press. 2000;24:73-263. Access mode: http://flora.huh.harvard.edu/china/mss/volume24/index.htm Accessed: 10.06.2020.

18. Walter G. Vegetation of the Earth. Ecological and physiological characteristics. Moscow: Progress, 1968, Vol. 1, 552 p. (In Russ.)

19. Dospekhov B.A. Field experiment technique. Moscow: Agropromizdat, 1985, 351 p. (In Russ.)

20. Kovalenko N.K. Ecological and physiological studies of lawn grasses in connection with their drought resistance, Lawns. 1977: 57-58. (In Russ.)

21. Ermakov A. I., Arasimovich V. V., Smirnova-Ikonnikova M. I., Yarosh N. P., Lukovnikova G. A. Biochemical research methods of plants. Leningrad: Kolos, 1972, 456 p. (In Russ.)

22. Broussard M.C. A horticultural study of Liriope and Ophiopogon: Nomenclature, morphology, and culture. Ph.D. dissertation, Louisiana State University, 2007, 141 p.