Salicylic acid (SA) controls growth and stress responses in plants. It also induces drought tolerance in plants. In this paper, four wheat (Triticum aestivum L.) cultivars with different drought responses were treated with SA in three levels of drain (90, 60, 30% of maximum field capacity) to examine its interactive effects on drought responses and contents of osmotic solutes that may be involved in growth and osmotic adjustment. Under drought condition, the cultivars Geza 164 and Sakha 69 had the plant biomass and leaf relative water content (LRWC) greater than the cultivars Gemaza 1 and Gemaza 3. In all cultivars, drought stress decreased the biomass, LRWC, and the contents of inorganic solutes (Ca, K, Mg) and largely increased the contents of organic solutes (soluble sugars and proline). By contrast, SA increased the biomass, LRWC and the inorganic and organic solute contents, except proline. Correlation analysis revealed that the LRWC correlated positively with the inorganic solute contents but negatively with proline in all cultivars. SA caused maximum accumulations of soluble sugars in roots under drought. These results indicated that SA-enhanced tolerance might involve solute accumulations but independently of proline biosynthesis. Drought-sensitive cultivars had a trait lowering Ca and K levels especially in shoots. Possible functions of the ions and different traits of cultivars were discussed.

Quantum dot (QD) growth on high (c3v) symmetry GaAs{111}
surfaces holds promise for efficient entangled photon sources. Unfortunately,
homoepitaxy on GaAs{111} surfaces suffers from surface roughness/defects
and InAs deposition does not natively support Stranski–Krastanov (SK) QD
growth. Surfactants have been identified as effective tools to alter the epitaxial
growth process of III-V materials, however, their use remains unexplored on
GaAs{111}. Here, we investigate Bi as a surfactant in III-As molecular beam
epitaxy (MBE) on GaAs(111)A substrates, demonstrating that Bi can eliminate
surface defects/hillocks in GaAs and (Al,Ga)As layers, yielding atomically-smooth
hillock-free surfaces with RMS roughness values as low as 0.13 nm. Increasing Bi
fluxes are found to result in smoother surfaces and Bi is observed to increase
adatom diffusion. The Bi surfactant is also shown to trigger a morphological
transition in InAs/GaAs(111)A films, directing the 2D InAs layer to rearrange into
3D nanostructures, which are promising candidates for high-symmetry quantum
dots. The desorption activation energy (UDes) of Bi on GaAs(111)A was measured
by reflection high energy electron diffraction (RHEED), yielding UDes = 1.7 ±
0.4 eV. These results illustrate the potential of Bi surfactants on GaAs(111)A and
will help pave the way for GaAs(111)A as a platform for technological applications
including quantum photonics.

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