PRODUCTION
continue to grow and to complete their maturation phases. It means also that a premature stem is not able to carry the heavy inflorescence. This is exact- ly what distinguishes gerbera from many other cut flowers that can be picked in their flower-bud stages. Therefore, we guide our gerbera growers that the right time for harvesting mature stems is: when two rings of male-flowers show their stamens (Figure 5). This practical instruction for harvesting gerbera flow- ers arises from the fact that there is a correlation of timing between the “Male phase” and the final stem maturity phase.
• The gerbera is a negative geotropic plant. Its stem growth pattern reacts to changes that occur in its
upright growing direction: If the stem growth is not interrupted, it will grow continuously in upright po- sition (Figure 6 A). A change in the upright position of the premature stem for a certain time is inducing and causing the negative geotropic growth phenomena. Shifting aside the stem from its upright position, while harvesting and packing, for example, toward horizontal or semi-horizontal positions, causes a growth reaction that turns the stems to upward posi- tion. Therefore, premature gerbera flower stems that are packed and shipped generally in horizontal posi- tion react later when being unpacked and placed in the vase, as expressed by an active upward growth that looks in the vase like sideward growth (Figure 6 B). A second active S-shape curve-growth reaction happens after a few days in the vase (Figure 6 C). Ma- ture rigid stems that finish their elongation phases are not affected the same way, as the geotropic sen- sitivity phase of the stem is already over.
• Mature strong stems are able to absorb without difficulties the amount of water needed for renewing
the turgor they have lost during the long shipment. On the contrary, stems that have been cut too early, before reaching their final lignification phase, have difficulties absorbing and transporting water after long shipment, and this fact shortens their vase life.
Dr. Yoseph Shoub is an agronomist and a gerbera breeder. You can reach him at
gerbera1@zahav.net.il
Epilogue
We can honestly declare: We are trying hard to se- lect gerbera varieties characterized by their flower quality, high productivity, long vase life, and stems endowed with strength and length. Our gerberas are long-lasting varieties in our catalogues, because of their positive horticultural qualities, resistance to Botrytis and Mildew, and having a reasonable num- ber of leaves and well-established root system. In ad- dition, our varieties are doing well in Subtropical and Mediterranean climates, and they are not as sensi- tive to low temperatures at night. All these qualities create the positive commercial feedback from our growers.
For more information visit
www.gerberaisrael.com
A - Flower stems before harvest. B - Curve growth of the stem after horizontal shipment. C - S-shape growth a few days after placing the stem in the in the vase.
A
B
C
Figure 6: Negative geotropic reaction of Bolivar flower stem.
18 FloralNews
www.SelectaCutFlowers.com
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