Biomics

We studied the effect of decreased ABA synthesize on growth characteristics and hormonal balance of lettuce plants under increased planting density (one or three (competing or grouped) plants in container). Herbicide fluridone used as inhibitor of AВA synthesis decreased not only ABA, but also photosynthetic pigments inhibiting plant growth when applied at high concentration (0.1 mg per l). Our preliminary experiments with single plants also showed that the presence in the soil solution of fluridone at very low concentration typical for growth regulators (0.001 mg per l) did not influence (at least during one week) either the content of pigments or the growth rate of shoots and roots and led to a mild physiological decline in ABA concentration in the lettuce plants. Experiments with 0.001 mg/l concentration of fluridone showed that the absence of ABA accumulation in grouped plants prevented growth inhibition typical for competing plants. These results confirmed important role of ABA in the growth inhibiting action of increased planting density. Furthermore, as in case of ABA, fluridone prevented distribution of IAA in favour of shoots of competing plants that was likely to level off the typical for shading increased ratio of leaf area to its mass (specific leaf area). Application of fluridone did not significantly affect shoot cytokinin concentration, whose level decreased under the influence of increased planting density as well as in the case of plants not treated with fluridone. The mechanisms of redistribution of ABA and IAA between shoots and roots are discussed in the report. Accumulation of ABA in the shoots of competing plants and the absence of such an accumulation under fluridone treatment suggests activation of hormone synthesis in the shoots of competing plants, while the absence of IAA distribution in favour of the shoots of fluridone-treated grouped plants suggests importance of ABA in the implementation of the effect.

lettuce, competition, growth, ABA, fluridone

1. Архипова Т.Н., Высоцкая Л.Б., Мартыненко Е.В., Иванов И.И., Кудоярова Г.Р. Участие цитокининов в реакции растений на присутствие конкурентов // Физиология растений. 2015. Т.62, № 4. С.560–570.
2. Веселов Д.С., Сабиржанова И.Б., Сабиржанов Б.Е., Чемерис А.В. Изменения эспрессии гена экспансина, содержания ИУК и скорости растяжения клеток листа растений кукурузы при засолении // Физиология растений. 2008. Т.55. С. 108-113.
3. Высоцкая Л.Б., Архипова Т.Н., Кузьмина Л.Ю., Трекозова А.В., Галимзянова Н.Ф., Кудоярова Г.Р. Рост растений салата в присутствии конкурентов и влияние внесения в их ризосферу ауксин продуцирующих микроорганизмов // Биомика. 2015. Т.7, № 4. С. 212-216.
4. Высоцкая Л.Б., Архипова Т.Н., Трекозова А.В., Кудоярова Г.Р. Реакция растений салата на плотность посадки и обработку ингибитором транспорта ауксинов // Биомика. 2015. Т.7, № 3. С. 153-156.
5. Дерфлинг К. Гормоны растений. Системный подход. М.: Мир, 1985. 206 с.
6. Шарипова Г.В., Веселов Д.С., Кудоярова Г.Р., Тимергалин М.Д. Влияние ингибитора рецепции этилена на рост, водный обмен и содержание абсцизовой кислоты у растений пшеницы при дефиците воды // Физиология растений. 2012. Т.59, № 4. С. 619.
7. Cagnola J.I., Ploschuk E., Benech-Arnold T., Finlayson S.A., Casal J.J. Stem transcriptome reveals mechanisms to reduce the energetic cost of shade-avoidance responses in tomato // Plant. Physiol. 2012. V.160. P. 1110–1119.
8. Davies W.J., Kudoyarova G.R., Hartung W. Long-distance ABA signaling and its relation to other signaling pathways in the detection of soil drying and the mediation of the plant’s response to drought // J. Plant Growth Regul. 2005. V.24. P. 285-295.
9. Parry A.D., Griffiths A., Horgan R. Abscisic acid biosynthesis in roots. II. The effects water-stress in wild-type and abscisic acid-deficient mutant (notabilis) plants of Lycopersicon esculentum Mill. // Planta. 1992. V.187. P. 192-197.
10. Pierik R., Sasidharan R., Voesenek L.A.C.J. Growth control by ethylene: adjusting phenotypes to the environment // J. Plant Growth Regul. 2007. V.26. P. 188–200.
11. Planes M. D., Niñoles R,Rubio L., Bissoli G., Bueso E, GarcíaSánchez M.J., Alejandro S., Gonzalez-Guzmán M., Hedrich R., Rodriguez P.L., José A., Fernández and Ramón Serrano. A mechanism of growth inhibition by abscisic acid in germinating seeds of Arabidopsis thaliana based on inhibition of plasma membrane H+ -ATPase and decreased cytosolic pH, K+ , and anions // J. Exp. Bot. 2015. V.66, No. 3. P 813–825.
12. Poorter H., Pepin S., Rijkers T., DeJong Y., Evans J.R., Korner C. Construction costs, chemical composition and payback time of high- and low-irradiance leaves // J. Exp. Bot. 2006. V.57. P. 355–371.
13. Salisbury F.J., Hall A., Grierson C.S., Halliday K.J. Phytochrome coordinates Arabidopsis shoot and root development // Plant J. 2007. V. 50. P. 429–438.
14. Shkolnik-Inbar D., Bar-Zvi D. ABI4 mediates abscisic acid and cytokinin inhibition of lateral root formation by reducing polar auxin transport in Arabidopsis // The Plant Cell. 2010. V.22. P. 3560–3573.
15. Veselov S.Yu., Kudoyarova G.R., Egutkin N.L., Gyuli-Zade V.G., Mustafina A.R., Kof E.K. Modified solvent partitioning scheme providing increased specificity and rapidity of immunoassay for indole 3-acetic acid // Physiol. Plant. 1992. V.86. P. 93–96.
16. Vysotskaya L.B., Arkhipova T.N., Timergalina L.N., Kudoyarova G.R. Effect of partial root excision on shoot water relations, IAA content and leaf extension in wheat seedlings // J. Plant Physiol. 2003. V.160. P. 1011-1015.
17. Vysotskaya L.B., Korobova A.V., Veselov S.Yu., Dodd I.C., Kudoyarova G.R. ABA mediation of shoot cytokinin oxidase activity: assessing its impacts on cytokinin status and biomass allocation of nutrient deprived durum wheat // Functional Plant Biology. 2009. V.36. P. 66–72.
18. Vysotskaya L., Wilkinson S., Davies W.J., Arkhipova T., Kudoyarova G. The effect of competition from neighbours on stomatal conductance in lettuce and tomato plants // Plant Cell Environ. 2011. V.34. P. 729–737.
19. Vysotskaya L.B., Veselov S.Yu., Kudoyarova G.R. Effect of competition and treatment with inhibitor of ethylene perception on growth and hormone concentration of lettuce plants // J. Plant Growth Regul. DOI: 10.1007/s00344-016-9653-7.