Tetraploid Citrumelo 4475 rootstocks improve diploid common clementine tolerance to long-term nutrient deficiency.

Nutrient deficiency alters growth and the production of high-quality nutritious food. In Citrus crops, rootstock technologies have become a key tool for enhancing tolerance to abiotic stress. The use of doubled diploid rootstocks can improve adaptation to lower nutrient inputs.

Influence of Rootstock Genotype and Ploidy Level on Common Clementine ( Hort. ex Tan) Tolerance to Nutrient Deficiency.

Nutrient deficiency, in particular when this involves a major macronutrient (N, P, and K), is a limiting factor on the performance of plants in their natural habitat and agricultural environment. In the citrus industry, one of the eco-friendliest techniques for improving tolerance to biotic and abiotic stress is based on the grafting of a rootstock and a scion of economic interest. Scion tolerance may be improved by a tetraploid rootstock.

Triploidy in Citrus Genotypes Improves Leaf Gas Exchange and Antioxidant Recovery From Water Deficit.

The triploidy has proved to be a powerful approach breeding programs, especially in since seedlessness is one of the main consumer expectations. Citrus plants face numerous abiotic stresses including water deficit, which negatively impact growth and crop yield. In this study, we evaluated the physiological and biochemical responses to water deficit and recovery capacity of new triploid hybrids, in comparison with diploid hybrids, their parents ("Fortune" mandarin and "Ellendale" tangor) and one clementine tree used as reference.

Triploid Citrus Genotypes Have a Better Tolerance to Natural Chilling Conditions of Photosynthetic Capacities and Specific Leaf Volatile Organic Compounds.

Low temperatures during winter are one of the main constraints for citrus crop. Polyploid rootstocks can be used for improving tolerance to abiotic stresses, such as cold stress. Because the produced fruit are seedless, using triploid scions is one of the most promising approaches to satisfy consumer expectations.

Nutrient Deficiency Tolerance in Citrus Is Dependent on Genotype or Ploidy Level.

Plants require essential minerals for their growth and development that are mainly acquired from soil by their roots. Nutrient deficiency is an environmental stress that can seriously affect fruit production and quality. In citrus crops, rootstock/scion combinations are frequently employed to enhance tolerance to various abiotic stresses.

Tetraploid citrus seedlings subjected to long-term nutrient deficiency are less affected at the ultrastructural, physiological and biochemical levels than diploid ones.

Nutrient deficiency has economic and ecological repercussions for citrus fruit crops worldwide. Citrus crops rely on fertilization to maintain good fruit output and quality, whereas new crop management policy aims to reduce fertilizers input. New rootstocks are needed to meet to this constraint, and the use of new tetraploid rootstocks better adapted to lower nutrient intake could offer a promising way forward.

Effect of chronic arsenic exposure under environmental conditions on bioaccumulation, oxidative stress, and antioxidant enzymatic defenses in wild trout Salmo trutta (Pisces, Teleostei).

The present study evaluates the relation between chronic arsenic (As) exposure in the natural distribution area of wild brown trout (Salmo trutta), oxidative stress and antioxidant enzymatic defenses. Two rivers of the same watershed were evaluated to highlight the correlation between As accumulation and the resulting stress: (i) the Presa River, which has high chronic As levels (2281.66 µg/L) due to past mining activity, and (ii) the Bravona River (control river).

Tetraploid Carrizo citrange rootstock (Citrus sinensis Osb.×Poncirus trifoliata L. Raf.) enhances natural chilling stress tolerance of common clementine (Citrus clementina Hort. ex Tan).

Low temperatures can disturb the development, growth and geographic distribution of plants, particularly cold-sensitive plants in the Mediterranean area, where temperatures can reach seasonally low levels. In citrus crops, scion/rootstock combinations are used to improve fruit production and quality, and increase tolerance to biotic and abiotic stresses. In the last decade, several studies have shown that tetraploid citrus seedlings or rootstocks are more tolerant to abiotic stress than their respective diploid.

Short- and long-term effects of carbohydrate limitation on sugar and organic acid accumulation during mandarin fruit growth.

Background: The physiological roles of organic acids in fruit cells are not fully understood, especially in citrus, whereas the decline in titratable acidity during ripening shown by many citrus fruits is due to the utilization of citric acid. We induced carbohydrate depletion by removing source leaves at two key periods in mandarin development (early and full citric acid accumulation). Then, we assessed the resulting changes in the short term (within 48 h) and long term (several weeks until ripening).

Metabolism in orange fruits is driven by photooxidative stress in the leaves.

In plants, stress signals propagate to trigger distant responses and thus stress acclimation in non-exposed organs. We tested here the hypothesis that leaves submitted to photooxidative stress may influence the metabolism of nearby fruits and thus quality criteria. Leaves of orange trees (Citrus sinensis (L.