PRODUCTION
– 750 mm), it develops upwards among the leaves, and it carries on its top the composed flower-head (the inflorescence). It has no leaves on it and does not have any kind of structural support (beside the lignified vascular system that conducts water and minerals), so therefore it needs distinct care. Dur- ing all the time of the stem growth, it is always the upper flexible section of the stem that continues to elongate. In the case of the gerbera, the length of the flexible section is about 10 -15 cm long, below the flower-head (Figure 3).
per flexible soft section of the gerbera stem is not strong enough to carry the heavy inflorescence, it might cause the bent-stems-performance. Note, that depending on the variety, the weight of the in- florescence at harvest time is 15 to 35 grams, while the inflorescence of the original species - Gerbera jamesonii - is only 2.5 to 7 grams. Furthermore, under greenhouse conditions the elon- gation rhythm is very fast, a fact that makes some diffi- culties for the grower to identify the exact maturation stage of the stem regarding its proper harvesting time. Thus, it is our goal to select gerbera varieties that produce flower stems that grow in upright position under summer conditions, as well as under winter conditions, flower stems which at harvest time will have already reached their final length and strength that make them able to carry the heavy inflores- cence without risk of bending. These kinds of stems also have the qualities that ensure their longevity throughout the long journey from the greenhouse to the vase of the customer.
T
How the stem quality affects our business - some points for our attention:
• It is important to realize that the energy reservoir in the gerbera stem (the sugars that are needed for
the growth) is very limited, as it has no leaves and its structure is built of vascular vessels. These facts mean that young premature stems and premature inflo- rescences are not able, after they have been cut, to
his upper section remains flexible and soft, while the lower parts of the stem are gradually lignified and become rigid (Figure 4). If the up-
A - Very young flower-stem. B, C - Young stems elongating among the plant’s leaves. D - Elongating stem with flower-head that has just passed the leaves’ level.
A
B
C
D
Figure 3. Elongation phases of the gerbera stem (flexible zone ----->)
B - Downward lignification at the stem-head starts early, and stops after few centimeters.
C - As long as stem elongation continues, the elongation zone remains flexible and not lignified.
A - Upward lignification starts at the stem-base, and continues during stem elongation.
Stem-head
Time for harvest gerbera stems:
• Never harvest gerbera stem before it lignifies ! !
• The vase-life of the stem is assured, only when most of the stem is lignified.
Stem-base Figure 4. Lignification phases of the gerbera stem. The same “Single-type” flower
“Female phase” today only styles are seen.
Stamens Stamens Styles Pistils
“Male phase” 2 days later yellow stamens are seen.
Figure 5. Practical indications for harvesting gerbera flower stem: when 2 circles of male flowers show their stamens.
www.SelectaCutFlowers.com FloralNews 17 12
Flexible zone
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