Differentiate responses of tetraploid and hexaploid wheat (Triticum aestivum L.) to moderate and severe drought stress: a cue of wheat domestication

Abstract

Differentiate mechanism of wheat species in response to contrasting drought stress gradients implies a cue of its long-term domestication. In the present study, three water regimes including well-watered control (WW, 80% field water capacity (FC)), moderate drought stress (MS, 50% FC,) and severe drought stress (SS, 30% FC) were designed to reveal different responses of eight wheat species (four tetraploid and four hexaploid) representing different breeding decades and genetic origins to drought stresses. The data indicated that 50% FC and 30% FC fell into the soil moisture threshold range of non-hydraulic and hydraulic root signal occurrence, respectively. In general, grain yield, grain number/spike weight per plant, aboveground biomass, harvest index (HI) and water use efficiency (WUE) were significantly higher in hexaploid species than those of tetraploid species under drought stress (P < .05). Particularly, nonhydraulic root signal was triggered and continuously operated under 50% FC, while hydraulic root signal was observed under 30% FC, respectively. Under 80% FC, the allometric exponent (ɑ) of M aboveground vs M root decreased from tetraploid to hexaploid (both were of <1), indicating that during the domestication, the hexaploid species allocated less biomass to root system. For the relationship of M ear vs M vegetative , the ɑ value was significantly greater in the hexaploid species, showing that hexaploid wheat distributed more biomass to ear than tetraploid to improve yield. Under 50% FC, this trend was enhanced. However, under 30% FC, there was no significant difference in the ɑ value between two species. Additionally, correlation analyses on yield formation affirmed the above results. Therefore, drought tolerance tended to be enhanced in hexaploid species under the pressure of artificial selection than that of tetraploid species. When drought stress exceeded a certain threshold, both species would be negatively seriously affected and followed a similar mechanism for better survival.

Green synthesis of spermine coated iron nanoparticles and its effect on biochemical properties of Rosmarinus officinalis

“…Drought stress significantly increased the hydrogen peroxide content in Rosmarinus officinalis. The increase in levels of H 2 O 2 content under drought stress has also been reported in previous studies 51,52 . This increase depends on the severity of the drought stress -SM is related to the increase in the activity of some important enzymes of the oxidative defense system, such as catalas (Figure 7D).…”

Differential roles of abscisic acid in maize roots in the adaptation to soil drought

“…Traditionally, crop grain yield would be affected by unfavorable abiotic factors including soil drought stress (Bakhshandeh et al, 2019; Figueroa‐Bustos et al, 2019; Jamieson et al, 1995). In recent years, however, more researches have shown that moderate or mild soil drying would not significantly inhibit crop growth to lower grain yield, but benefit for yield improvement (Fang et al, 2017; Gui et al, 2021; Teng et al, 2022). In this study, change in kernel yield of maize exhibited a simple parabolic trend with the opening down as the soil water potential (SWP) decreased or ABA in roots increased (Table 1; Figure 6).…”

Effects of water stress on plant volatile emission and insect oviposition preference in an agroecosystem

“…These remained seedlings were treated by one of the water treatments before oviposition selection trials and plant volatile collection. We tested three levels of water treatment: (1) well‐watered treatment (700 mL of water every 4 days), achieving 80%–70% water capacity of the field; (2) moderately water‐stressed treatment (450 mL of water every 4 days), keeping 60%–55% water capacity of the field; and (3) severely watered‐stressed treatment (230 mL of water every 4 days), remaining 40%–35% water capacity of the field (Duan et al, 2021; Gui et al, 2021). There were 20 plastic pots per water treatment for a total of 60 pots.…”