Before carnivorous plants are carnivorous plants, they need to depend on their own roots and absorption from non-insect sources. Every seedling derives 100% of their food directly through their root system. As this root system grows, so does the plant's leaves and stems until finally large enough pitchers can start supplying SOME of their nutrients. Insects provide mostly nitrogen, an item their environment usually lacks in. Other factors also play an important role in their growth cycle. It is NOT merely enough that the nepenthes captures its prey for growth and development. Aside from nitrogen, other factors contribute to growth. Phosphorus is also required. Nepenthes can capture some phosphorus from insect matter, but it is not enough! Phosphorus is usually abundant in some soil mineral content, so with ample water and light, nepenthes can absorb SOME of this mineral from the soil. Phosphorus is required for strong stems, good root systems and for flowering, fruit and seed development. Then all plants also require potassium. This can be derived from insect matter, but can also be absorbed from decomposing matter in the soil through their ROOTS. Other minerals required include calcium (also derived usually through their roots via soil composition), iron, magnesium, zinc, etc. usually found in abundant quantities in the soil.
If one looks carefully of the kind of roots that nepenthes have, they seem almost like a net. Roots are very fine, black in color, and form an extensive network of rebranching parts. This kind of rot systems is for one reason only. Its to utilize whatever mineral source comes their way via a stream of rainwater dissolving minerals and nutrients during a heavy down pour, or shifts in new soil media from landslides, falling leafy matter, fruits and other debris reaching the surface. After a rapid breakdown in the tropics, awaiting are many competitors seeking the exact same nutrient soup. This a fine network of roots enable rapid absorption to occur.
With the question regarding fertilizing. The answer is YES! It should be dilute and NO, its not something new for nepenthes. Nepenthes has been using both their roots and traps for their existence.
New evidence on the sp. Viking and thorelii shows that many form tubers or thickened storage organs underground to allow plants to come back from fires, drought or their monsoon season. Storage in roots are derived exclusively through root absorption and not from pitcher nutrient utilization. But when fertilizing, always in dilute amounts since their fine roots can capture a great deal from just a splash of nutrients in solution.
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