Canopy-applied silicon is an effective strategy for reducing sweet cherry cracking

Fruit cracking caused by rainfall prior to harvest, a major problem in sweet cherry production, is being exacerbated by climate change. Currently, pre-harvest spraying with calcium salt solutions is the prevalent technique to reduce fruit cracking in cherry orchards not covered by plastic roofs. This study evaluated the effectiveness of canopy-applied silicon in the reduction of sweet cherry cracking under different field conditions. Four field trials were conducted on mature trees of the cultivars Van, New Star, and Emperor Francis. Treatments included water (control), calcium chloride, and sodium silicate. Multiple sprays (three) were applied weekly from fruit onset of color to approximately 1 week before harvest. The results showed that under conditions conducive to cracking, sodium silicate reduced the percentage of cracked fruits to a similar or larger extent than calcium chloride. This study highlights how canopy-applied silicon sources may effectively contribute to reducing cherry cracking, acting as an alternative technique to other preventive methods

Characterization of VOCs Emitted by Foliage of Grapevine cv. Isabella for Prospecting Innovative Cropping Systems

Volatile organic compounds play an important role in communication within plants as well as with other organisms. In this work we identified the volatile organic compounds (VOCs) emitted from the foliage of the grapevine cv. Isabella, a largely known hybrid of Vitis vinifera × Vitis labrusca. Our data show 25 VOCs emitted by cv. Isabella. Different compound classes were found, including alcohols, hydrocarbons, esters, terpenes, ketones, and a green leaf volatile (GLV). The study highlighted differences between volatile profiles for diurnal and nocturnal treatments. The compounds: trans-3-dodecene, 5,5 dibutylnonane, ethyl 2-methyllactate, 2-hexanol, 3-ethyl-2-heptanol, 3-nonanol, and 2-nonanol, have not been previously reported for Vitis vinifera foliage. Notably, eight compounds emitted by cv. Isabella, 1-heptanol, 1-octanol, 2-hexanol, 2-nonanone, β-pinene, camphene, cis-hexenyl acetate, and phenethyl alcohol, are of relevant interest for their role in plant defense. New knowledge on the emission of these compounds in cv. Isabella can help to understand the mechanisms of pathogen tolerance of this genotype and could be an important step in prospecting innovative cropping systems

Alkaliphiles : The Emerging Biological Tools Enhancing Concrete Durability

Concrete is one of the most commonly used building materials ever used. Despite it is a very important and common construction material, concrete is very sensitive to crack formation and requires repair. A variety of chemical-based techniques and materials have been developed to repair concrete cracks. Although the use of these chemical-based repair systems are the best commercially available choices, there have also been concerns related to their use. These repair agents suffer from inefficiency and unsustainability. Most of the products are expensive and susceptible to degradation, exhibit poor bonding to the cracked concrete surfaces, and are characterized by different physical properties such as thermal expansion coefficients which are different to that of concrete. Moreover, many of these repair agents contain chemicals that pose environmental and health hazards. Thus, there has been interest in developing concrete crack repair agents that are efficient, long lasting, safe, and benign to the environment and exhibit physical properties which resemble that of the concrete. The search initiated by these desires brought the use of biomineralization processes as tools in mending concrete cracks. Among biomineralization processes, microbially initiated calcite precipitation has emerged as an interesting alternative to the existing chemical-based concrete crack repairing system. Indeed, results of several studies on the use of microbial-based concrete repair agents revealed the remarkable potential of this approach in the fight against concrete deterioration. In addition to repairing existing concrete cracks, microorganisms have also been considered to make protective surface coating (biodeposition) on concrete structures and in making self-healing concrete. Even though a wide variety of microorganisms can precipitate calcite, the nature of concrete determines their applicability. One of the important factors that determine the applicability of microbes in concrete is pH. Concrete is highly alkaline in nature, and hence the microbes envisioned for this application are alkaliphilic or alkali-tolerant. This work reviews the available information on applications of microbes in concrete: repairing existing cracks, biodeposition, and self-healing. Moreover, an effort is made to discuss biomineralization processes that are relevant to extend the durability of concrete structures