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Calcium transport in apple trees
1Crop Research Division Agricultural Research Service, United States Department of Agriculture, Beltsville, Maryland 20705.
Plant Physiology
|June 1, 1970
Summary
Calcium movement in apple seedlings is influenced by nitrogen source and plant growth regulators. Genetic factors also affect how readily calcium translocates to leaves.
Area of Science:
- Plant Physiology
- Agricultural Science
- Nutrient Transport
Background:
- Calcium (Ca) is essential for plant cell wall structure and signaling.
- Understanding Ca uptake and translocation is crucial for apple tree health and fruit quality.
- Factors influencing Ca movement in woody plants are not fully elucidated.
Purpose of the Study:
- To investigate the factors affecting calcium (Ca) translocation in apple seedlings.
- To determine the role of nitrogen form, plant growth regulators, and genetic variation in Ca movement.
- To elucidate the mechanism of Ca translocation in the stem.
Main Methods:
- Radioactive calcium-45 ((45)Ca) was applied to the roots of apple seedlings.
- Different nitrogen sources (nitrate vs. ammonium) were used.
- Plant growth regulators (kinetin, benzyladenine, boron) were applied as sprays.
- Ca movement and accumulation in different leaf tissues were analyzed.
- Genetic differences in Ca translocation were assessed by comparing seedlings with juvenile and mature leaf characteristics.
Main Results:
- Applied (45)Ca readily translocated to developing apple leaves.
- Kinetin, benzyladenine, and boron sprays enhanced Ca movement.
- Nitrate as the nitrogen source increased Ca movement and accumulation in mature leaves.
- Ammonium as the nitrogen source promoted Ca movement into new leaves.
- Stem translocation of Ca involves a nonspecific ion exchange, potentially related to lignin.
- Genetic variations in Ca uptake and translocation were observed among seedlings.
- Seedlings with juvenile leaf characteristics showed more efficient Ca translocation to mature leaves.
Conclusions:
- Nitrogen form and plant growth regulators significantly influence calcium translocation in apple seedlings.
- Nonspecific ion exchange mechanisms, possibly involving lignin, facilitate Ca movement in the stem.
- Genetic factors play a role in calcium uptake and translocation efficiency.
- Calcium translocation patterns in apple trees resemble those in herbaceous plants.
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