ISHS Acta Horticulturae 450: International Symposium Growing Media and Plant Nutrition in Horticulture
PLANT QUALITY AND GROWTH OF HYDRANGEA X HYBRIDA AS INFLUENCED BY TEMPERATURE AND WATER QUANTITY (REFEREED) |
| Authors: | R. Roeber, H. Haas |
| Keywords: | Plant quality, shoot growth, stress, water quantity, growth retardant, temperature, cool morning, Hydrangea x hybrida |
| Abstract:
The restricted permission of the use of growth retardants by German authorities lead to reflections about natural methods of growth regulation. Therefore, a trial was conducted, where the influence of substrate moisture and air temperature was investigated. Plants of the varieties ‘Hermann Dienemann’ (red), ‘Nymphe’ (white) and 'Renate Steiniger (blue) were supplied with three different amounts of water and cultivated during the forcing period with and without cool morning (= CM; temperature drop). As a control, plants were treated either with Daminocide or Flurprimidol or without growth retardant. Decreasing moisture of the substrate and the application of growth retardant lead to a reduction of height, diameter, and leaf area of the plants. If the water supply during stress was adjusted to the periodic demand of the plant, the external quality of the plants stressed by drought was comparable to the quality of those treated with growth retardants instead. The supply of large quantities of water at the end of the forcing period do no longer influence the length of the shoot, but favours flower development. Cool morning has a strong influence on shoot height, too. But it leads to a lengthening of the cultivation time. It can be concluded, that plants cultivated “cool and dry” are very compact, healthy, and possess a high quality grade. | |
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