Field experiments were conducted on wheat to study the effects of foliar-applied iodine (I) alone, Zn (zinc) alone and a micronutrient cocktail solution containing I, Zn, Se (selenium) and Fe (iron) on grain yield and grain concentrations of micronutrients. Plants were grown over 2 years in China, India, Mexico, Pakistan, South Africa and Turkey. Grain-Zn was increased from 28.6 mg kg-1 to 46.0 mg-1 kg with Zn-spray and 47.1 mg-1 kg with micronutrient cocktail spray. Foliar-applied I and micronutrient cocktail increased grain I from 24 μg kg-1 to 361 μg kg-1 and 249 μg kg-1, respectively. Micronutrient cocktail also increased grain-Se from 90 μg kg-1 to 338 μg kg-1 in all countries. Average increase in grain-Fe by micronutrient cocktail solution was about 12%. The results obtained demonstrated that foliar application of a cocktail micronutrient solution represents an effective strategy to biofortify wheat simultaneously with Zn, I, Se and partly with Fe without yield trade-off in wheat.

Background and Aims Understanding the changes in below-ground bud bank density and composition along a climatic gradient is essential for the exploration of species distribution pattern and vegetation composition in response to climatic changes. Nevertheless, investigations on bud banks along climatic gradients are still scarce. The below-ground bud bank is expected to be reduced in size in arid conditions, and costly, bud-bearing organs with long spacers would be replaced by more compact forms with buds that are better protected than those found in moist conditions. Methods How total bud density and composition (different bud bank types) change with aridity (calculated value 0·43–0·91), mean annual precipitation (MAP; 93–420 mm) and mean annual temperature (MAT; −1·51 to 6·93 °C) was tested at 21 sites along a 2500-km climatic gradient in the temperate steppe of northern China. Key Results The relationship between below-ground bud bank density and precipitation/aridity was fundamentally changed along the climatic gradient. Bud bank density increased first and then decreased along the aridity and MAP gradients, the turning points being aridity=0·67 and MAP=260 mm, respectively, while it decreased consistently with increasing MAT. The proportion of the bud bank that comprised tiller buds or dicotyledonous herb buds fluctuated along the aridity gradient. The proportion of rhizome buds was higher at relatively moist sites (aridity 0·75). Conclusions Belowground bud bank density decreases towards the dry, hot end of the climatic gradient. Based on the distribution of bud types along the climatic gradient, bulb buds and tiller buds of tussock grasses seem to be more resistant to environmental stress than rhizome buds. The dominance of annual species and smaller bud banks in arid region implies that plant reproductive strategies and vegetation composition will be shifted in scenarios of increased drought under future climate change.