Factors Involved in Fruit Calcium Deficiency Disorders

Abstract

Understanding the mechanisms of calcium (Ca 2þ ) deficiency disorder development in plants has been a challenge for more than a 100 years. Previous studies support the hypothesis that Ca 2þ deficiency disorders can be triggered by mechanisms that reduce plant Ca 2þ uptake from the soil, fruit Ca 2þ uptake from the plant, and Ca 2þ translocation within the fruit, and also result in abnormal regulation of cellular Ca 2þ partitioning. Plant Ca 2þ uptake can be determined by Ca 2þ content and availability in the soil, root growth, activity of apoplastic and symplastic pathways of root Ca 2þ uptake, as well as uptake competition between Ca 2þ and other nutrients. Fruit Ca 2þ uptake is determined by Ca 2þ content in the xylem sap, and xylem/phloem ratio of fruit sap uptake, which is affected by the rates of leaf and fruit transpiration and growth. Calcium translocation to distal fruit tissue, containing the lowest fruit Ca 2þ content and the highest susceptibility to Ca 2þ deficiency disorders, is potentially dependent on the cell wall Ca 2þ -binding capacity and symplastic Ca 2þ uptake by the tissue at the peduncle end of the fruit, abundance of functional xylem vessels connecting peduncle and distal fruit tissues, as well as the hydrostatic gradient required for Ca 2þ translocation towards the distal tissue. Cellular Ca 2þ partitioning is defined by the activity of Ca 2þ channels, Ca 2þ ATPases, and Ca 2þ exchangers present in cellular membranes, as well as the capacity of the cell wall to bind Ca 2þ , and the formation of Ca 2þ precipitates in different cellular compartments. Therefore,

Impactos Do Nível De Irrigação E Da Cobertura Do Solo Na Cultura Do Tomateiro

“…A manutenção da umidade ideal do solo auxilia na absorção de cálcio pelas raízes (OLLE & BENDER, 2009). Como esse distúrbio está relacionado à deficiência de cálcio na planta, a manutenção da umidade do solo é importante tanto para permitir sua movimentação por fluxo de massa, quanto para possibilitar seu transporte via xilema até os frutos (FREITAS & MITCHAM, 2012). Contudo, a alta umidade do solo, devido às precipitações ocorridas no período de maior demanda de cálcio pelas plantas, provavelmente impediu a variação de umidade no solo entre os tratamentos com e sem cobertura plástica, justificando a ausência de resultados divergentes para essas características.…”

Bitter pit in apples: pre- and postharvest factors: A review

“…Freitas & Mitcham (2012), based on a review of numerous studies of Ca deficiency factors, concluded that this phenomenon is the result of complex physiological processes which lead towards a decrease of Ca concentration in plant tissues, particularly the cell. Furthermore, the key role in the formation of bitter pit could have the translocation of Ca from the peduncle to the calyx part of the fruit.…”

Food shortage in Zimbabwe: Can wild cereal grains be an alternative source of nutrition?

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