Boron deficiency in bananas
Boron is the most commonly deficient micronutrient in banana plantations. Boron’s primary role in banana is to act as a key component in a number vital process such as structure integrity of cell walls, cell division, root development, and membrane permeability of potassium (K+).
Boron is necessary for:
- Proper growth and development
- Pulp consistency
- Sucker development
Incomplete expansion and unfolding of the youngest leaf is probably the most typical symptom of boron deficiency. In very severe cases, interveinal chlorosis and leaf malformation occur. The leaves may be narrow, rolled, and incompletely developed. Sucker development is likely to be very poor.
Leaf streaking
Boron deficiency first results in the development of small chlorotic streaks aligned perpendicular to and crossing the primary veins of the leaf blade. As the deficiency becomes more severe, the chlorotic streaks become longer and more concentrated, eventually extending through the leaf and, in some cases, appearing as slight protrusions on the lower surface.
Leaf streaking has been recorded in cases of boron deficiency. However, such streaks usually coalesce, forming patches, and ultimately become large necrotic patches. Boron deficiency is distinguished from sulfur deficiency by the absence of necrotic patches and the appearance of malformed leaves.
Blackening in the center of the pulp of the fruit has been observed in sand culture experiments. In the field the presence of amber colored gummy deposits (mostly towards the flower end) has also been associated with boron deficiency.