Exogenously Applied Plant Growth Regulators Enhance the Morpho-Physiological Growth and Yield of Rice under High Temperature.
A 2-year experiment was conducted to ascertain the effects of exogenously applied plant growth regulators (PGR) on rice growth and yield attributes under high day (HDT) and high night temperature (HNT). Two rice cultivars (IR-64 and Huanghuazhan) were subjected to temperature treatments in controlled growth chambers and four different combinations of ascorbic acid (Vc), alpha-tocopherol (Ve), brassinosteroids (Br), methyl jasmonates (MeJA), and triazoles (Tr) were applied. High temperature severely affected rice morphology, and also reduced leaf area, above-, and below-ground biomass, photosynthesis, and water use efficiency, while increased the leaf water potential of both rice cultivars. Grain yield and its related attributes except number of panicles, were reduced under high temperature. The HDT posed more negative effects on rice physiological attributes, while HNT was more detrimental for grain formation and yield. The Huanghuazhan performed better than IR-64 under high temperature stress with better growth and higher grain yield. Exogenous application of PGRs was helpful in alleviating the adverse effects of high temperature. Among PGR combinations, the Vc+Ve+MejA+Br was the most effective treatment for both cultivars under high temperature stress. The highest grain production by Vc+Ve+MejA+Br treated plants was due to enhanced photosynthesis, spikelet fertility and grain filling, which compensated the adversities of high temperature stress. Taken together, these results will be of worth for further understanding the adaptation and survival mechanisms of rice to high temperature and will assist in developing heat-resistant rice germplasm in future.
National Key Laboratory of Crop Genetic Improvement, MOA Key Laboratory of Crop Ecophysiology and Farming System, College of Plant Science and Technology, Huazhong Agricultural University Wuhan, China.
Shah
S
Fahad
College of Resources and Environment, Huazhong Agricultural University Wuhan, China.
Saddam
S
Hussain
Department of Horticulture, Northeast Agricultural University Harbin, China.
Shah
S
Saud
Department of Agricultural Extension Education and Communication, The University of Agriculture, Peshawar Peshawar, Pakistan.
Shah
S
Hassan
Department of Arid Land Agriculture, Faculty of Meteorology, Environment and Arid Land Agriculture, King Abdul Aziz University Jeddah, Saudi Arabia.
Zahid
Z
Ihsan
National Key Laboratory of Crop Genetic Improvement, MOA Key Laboratory of Crop Ecophysiology and Farming System, College of Plant Science and Technology, Huazhong Agricultural University Wuhan, China.
Adnan N
AN
Shah
National Key Laboratory of Crop Genetic Improvement, MOA Key Laboratory of Crop Ecophysiology and Farming System, College of Plant Science and Technology, Huazhong Agricultural University Wuhan, China.
Chao
C
Wu
College of Resources and Environment, Huazhong Agricultural University Wuhan, China.
Muhammad
M
Yousaf
Department of Environmental Sciences, COMSATS Institute of Information Technology Vehari, Pakistan.
Wajid
W
Nasim
Department of Biological Sciences, Faculty of Sciences, King Abdulaziz University Jeddah, Saudi Arabia.
Hesham
H
Alharby
Department of Arid Land Agriculture, Faculty of Meteorology, Environment and Arid Land Agriculture, King Abdul Aziz University Jeddah, Saudi Arabia.
Fahad
F
Alghabari
National Key Laboratory of Crop Genetic Improvement, MOA Key Laboratory of Crop Ecophysiology and Farming System, College of Plant Science and Technology, Huazhong Agricultural UniversityWuhan, China; Hubei Collaborative Innovation Center for Grain Industry, Yangtze UniversityHubei, China.
Jianliang
J
Huang
cultivars; high night temperature; morpho-physiological growth; plant growth regulators; spikelet fertility; water use efficiency