Project Number: 3607-21000-011-12
Project Type: Specific Cooperative Agreement

Start Date: Sep 21, 2006
End Date: Jun 30, 2009

Objective:
A current problem facing greenhouse growers is distorted terminal growth of pansy, petunia, and gerbera plugs. The problem is thought to be either a boron or calcium deficiency. The occurrence and severity of the problem can vary: from year to year; within a particular period of the season; by stage of plant development; environmental conditions; by geographical; and by cultivar. This research will investigate the mechanisms leading to this problem in pansy, petunia, and gerbera plugs, determine the best management practices to avoid the problem, determine critical tissue levels in plants exhibiting deficiency symptoms, and establish optimal sampling methods to use for measuring boron and calcium levels in tissue. In addition, research will be conducted to determine the symptomology of nutrient deficiencies in floriculture crops including gerbera, cyclamen, and hydrangea. This will aid growers in diagnosing plant problems.

Approach:
The current hypothesis is that environmental conditions are a primary component needing investigation in order to determine and correct the cause of distorted growth of the plugs. In addition, a thorough investigation will also require determining the extent in which nutritional factors influence boron and calcium availability. Therefore a number of experiments are proposed. 1) Induce symptoms of boron and calcium deficiency hydroponically for gerbera, pansies, and petunias. 2) Determine the effect of pH on the induction of B deficiency. 3) Determine the effect of changing the bulk density of the substrate on plug B and Ca uptake. 4) Determine the effect of relative humidity on B and Ca uptake. 5) Determine the effect of induced drought stress on plugs and the B and Ca uptake. 6) Determine the effect of calcium interacting with B availability. 7) Determine the effects of leaf temperature and relative humidity on B and Ca uptake. 8) Determine the symptomology of nutrient deficiencies on plant growth and development