back / zurück
Abgeschickt von Camiel de Jong am 26 August, 2002 um 19:37:46
Here I have some pictures of a variegated C. pubescens plus their story.
Four years ago I sowed C. parviflorum ssp pubescens from a green pod obtained from a plant at the botanical garden here in Wageningen. The sowing was not very successfull and I only obtained a few seedlings. Although the plants were small I gave them a vernalisation period in vitro but did not deflask them. Instead I put them in light and let them grow for another year in the flask after which I vernalized them again. By then the seedlings had grown out to a pretty impressive size having on average 15-20 roots of around 15-20 cm. I planted them out after the vernalization period in a mix of perlite, seramis, vulca (1:1:1, (v/v/v)) and some I gave to a friend. That year they emerged but the shoots were not very big and they looked like they wanted to grow vigorously at first but slowed down. As a matter of fact I did not fertilize them as I was afraid that I might feed any funghi that could attack the still vulnerable plants. All the plants looked healthy and green however. During the year they developed nice new and bigger buds. However, when the plants emerged the next year the biggest seedlings were all variegated and only the vessels of the leaves were green (see pictures). Notice that the small seedlings are not affected. The leaves did not develop very well and the white parts turned brown. Only one affected plant survived in the end and its leaves (what was left of it) have turned green.
My conclusion is that this type of variegation might be caused by a lack of nutrients. This may be even caused by a lack that was already built up in the previous year. When the shoot emerges not enough stored nutrients are mobilized and the shoot is affected. An indication for this assumption is that the tissue around the veins is green but tissue further away is not. In the previous year the plant were fertilized with a diluted commercial fertilizer when the shoot was already mature. Besides macro nutrients these fertilizers contain the trace elements and iron but not magnesium. Both of the latter two elements are implicated in the production of chlorophyl. Normally magnesium is readily available from the soil but I guess it is not available in the seramis-perlite-vulca mixture. Seedlings that like calcarous soils respond well to adding dolokal granules that contain 5% magnesium. The seedlings turn greener and are less affected by tip browning. It remains to be determined which of the elements or if both are responsible for the improvement.
back / zurück