Exogenous 2-(3,4-Dichlorophenoxy) triethylamine ameliorates the soil drought effect on nitrogen metabolism in maize during the pre-female inflorescence emergence stage

Abstract2-(3,4-Dichlorophenoxy) triethylamine (DCPTA) regulates many aspects of plant development; however, its effects on soil drought tolerance are unknown. We pre-treated maize (Zea mays L.) by foliar application of DCPTA and subsequently exposed the plants to soil drought and rewatering conditions during the pre-female inflorescence emergence stage. Exogenous DCPTA significantly alleviated drought-induced decreases in maize yield, shoot and root relative growth rate (RGR), leaf relative water content (RLWC), net photosynthetic rate (Pn), stomatal conductance (Gs) and transpiration rate (Tr), nitrate (NO3−), nitrite (NO2−), and soluble protein contents, and nitrate reductase (NR), nitrite reductase (NiR), isocitrate dehydrogenase (ICDH), alanine aminotransferase (AlaAT) and aspartate aminotransferase (AspAT) activities; increases in the intercellular CO2 concentration (Ci), the ammonium (NH4+) and free amino acid contents, and the glutamate dehydrogenase (GDH) and protease activities. Simultaneously, exogenous DCPTA improved the spatial and temporal distribution of roots and increased the root hydraulic conductivity (Lp), flow rate of root-bleeding sap and NO3− delivery rates. Moreover, Exogenous DCPTA protected the chloroplast structure from drought injury. Taken together, our results suggest that exogenous DCPTA mitigates the repressive effects of drought on N metabolism and subsequently enhances drought tolerance during the pre-female inflorescence emergence stage of maize.HighlightsThis is the first article that explores the effects of DCPTA on nitrogen metabolism and the first article that explores the effects of DCPTA on crops under soil drought conditions.

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Nitrogen Metabolism and Photosynthesis in Leymus chinensis in Response to Long-term Soil Drought

Journal of Plant Growth Regulation ◽

10.1007/s00344-006-0043-4 ◽

2006 ◽

Vol 25 (3) ◽

pp. 252-266 ◽

Cited By ~ 54

Author(s):

Z. Z. Xu ◽

G. S. Zhou

Keyword(s):

Nitrogen Metabolism ◽

Leymus Chinensis ◽

Soil Drought

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Elevated CO2 reduces the drought effect on nitrogen metabolism in barley plants during drought and subsequent recovery

Environmental and Experimental Botany ◽

10.1016/j.envexpbot.2011.02.011 ◽

2011 ◽

Cited By ~ 17

Author(s):

Anabel Robredo ◽

Usue Pérez-López ◽

Jon Miranda-Apodaca ◽

Maite Lacuesta ◽

Amaia Mena-Petite ◽

...

Keyword(s):

Nitrogen Metabolism ◽

Elevated Co2 ◽

Drought Effect ◽

Subsequent Recovery

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Experimentally disentangling drought from heat stress effects in European beech trees

10.5194/egusphere-egu2020-10084 ◽

2020 ◽

Author(s):

Günter Hoch ◽

Nikita Häfeli ◽

Ansgar Kahmen

Keyword(s):

High Temperatures ◽

Air Temperature ◽

European Beech ◽

Temperature Treatment ◽

Tree Level ◽

Soil Drought ◽

Water Addition ◽

Mature Trees ◽

Drought Effect ◽

Tree Survival

Hot summer droughts are becoming increasingly frequent in temperate biomes world-wide. In summer 2018, several weeks of drought paired with constantly high temperatures led to significant forest decline and mortality in mature trees in central Europe. In many regions, European beech was one of the most drought-sensitive tree species in 2018 with many trees showing partial or complete crown dieback by the end of the year, preceded by early leaf browning in mid-summer. So far it is disputed, if these symptoms were solemnly driven by a direct drought effect from dried-out soils, or if they were additionally amplified by hot mid-day temperatures and high atmospheric vapor pressure deficits (VPD).In a recent study we therefore aimed to disentangle the effects of soil drought, air temperature and VPD on beech seedlings in a full-factorial experiment. Two-year old beech saplings were exposed to either cooler (daily max. temperature 24&#176;C) or warmer (daily max. temperature 35&#176;C) temperatures in walk-in phytotrons. Within each temperature treatment, half of the saplings were grown at either high or low relative humidity resulting in the same low or high mid-day VPD in both temperature treatments (0.7 vs. 2 kPa).Finally, half of the saplings from each temperature-VPD treatment combination where exposed to drought by stopping irrigation in July, with only compensatory water addition among pots to ensure the same dry-out rate among treatments (i.e. no faster soil drying at high VPD). Across all temperature-VPD treatment combinations, drought led to very similar decreases of stomatal conductance, photosynthesis and pre-dawn leaf water potential. There was only a tendency for an approximately 1 week earlier decline of Fv/Fm (leaf fluorescence) under drought at high VPD conditions, pointing at slightly faster stress occurrence at the leaf-level at very low air humidity. Neither high temperatures, nor high VPD induced stress symptoms at the leaf or whole-tree level in well-irrigated saplings. Overall, air temperature and VPD had no significant effect on the saplings' survival time under drought, with saplings from all temperature-VPD combinations dying on average after about 100 days into drought. Therefore, at the same decreasing rate of soil water availability, we did not find additional negative effects of warm temperatures or high VPD on tree survival, indicating that European beech is per se quite robust against heat and high VPD stress.

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