Post by stonejaguar on Apr 20, 2010 3:23:32 GMT 7
Greetings:
Since the form & function of Nepenthes lowii upper pitchers is still the subject of some good-natured debate, I thought that I would add some "fuel to the fire" as it were with some recent observations.
During the course of spring cleaning of my collection this year, I have been keeping my eye on a rather large N. lowii from the Gunung Mulu population (ex-Wistuba, 2000) in order to figure out how best to display it. This plant has produced some very nice, large uppers in the past but it has recently slowed down a bit from a bit of grower neglect, although it does now have a very large rosetted offset that also produces uppers. Since we are in the middle of the dry season and the plant is on a shaded bench located outside where it receives a lot of filtered sunshine, I have been watering it almost daily to make sure that the plant was well-hydrated prior to transplanting it to a larger pot and moving it to a more exposed position where it could scramble over higher supports.
As part of the watering regimen, a couple weeks back I started filling up the upper pitchers (incl. one that is partly dried) to the edge of the peristome every morning with distilled water. At first, the fact that the pitchers were emptied down to the pitchers own viscous fluid at the bottom every evening seemed fairly logical, and I put this loss down to rapid evaporation due to relatively low RH, coupled with the wide-open aspect of the pitchers' mouths, etc. However, since late last week I began to note that the rapid disappearance of this water from the pitchers could not be explained by evaporation, nor tipping, nor any small vertebrate drinking the pitcher contents, nor even my resident CP gremlins. This past weekend, when I was out in the garden for the entire day on both Saturday and Sunday and was thus able to assure myself that nothing was interfering with the pitcher processes, I started a trial to see how fast the pitchers absorbed this water and found - to my complete surprise - that all three extant uppers were draining this water over the course of several hours, in spite of the fact that we had some rainstorm late last week and RH hovered between 65 and 71% and conditions were quite still. Basically, I had to refill the pitchers every 4 hours starting at dawn to keep them with the water level above the pitchers' "waist, and inspections made even 2 hours after filling the pitchers showed a visible drop in the water level below the edge of the peristome. Pitchers of many sizes of other Nepenthes spp. grown nearby with more traditionally shaped pitchers did not lose any significant amounts of pure water added to their pitcher contents late last week as a control and some very large N. truncata pitchers that had been completely filled by pouring rain on Thursday evening showed no water loss to evporation or absorption at all.
I am well aware that slightly dehydrated Nepenthes plants and healthy but "limp" pitchers absorb pure water easily, but have never noted anything as dramatic as this. At transplant on Saturday, I found that the plant had a vigorous, very healthy looking root system and the leaves are turgid and healthy-looking and, indeed, during the entire process the plant has never looked water stressed in any way. The plant is clearly using its roots to take up some of its water needs, but it *appears* that this plant is absorbing a remarkable amount of water every day from its pitchers, and that this speed of this process continues apparently unabated after almost two weeks of topping off pitchers from 1 to 4 times daily. Since the catchment face (=upper half of the pitcher) immediately below the pitcher lid of N. lowii is very smooth and glossy even on close inspection, it may be that this region is adapted to facilitate uptake of water. Since N. lowii is known to be a true epiphyte (as opposed to also growing as a terrestrial or hemiepiphyte) on some occasions and many epiphytic plants have special adaptations to catch and store water in what can be surprisingly hostile envirnments, it may be that this sp. is *better* than many of its cogeners at this task, and absorbs the abundant rainfall caught in its wide open pitchers as a matter of course and that this function may be of near equal importance to the apparent "birds toilet bowl" role they play.
I would enjoy hearing others' experiences with this plant in this regard.
Cheerio,
Jay
Since the form & function of Nepenthes lowii upper pitchers is still the subject of some good-natured debate, I thought that I would add some "fuel to the fire" as it were with some recent observations.
During the course of spring cleaning of my collection this year, I have been keeping my eye on a rather large N. lowii from the Gunung Mulu population (ex-Wistuba, 2000) in order to figure out how best to display it. This plant has produced some very nice, large uppers in the past but it has recently slowed down a bit from a bit of grower neglect, although it does now have a very large rosetted offset that also produces uppers. Since we are in the middle of the dry season and the plant is on a shaded bench located outside where it receives a lot of filtered sunshine, I have been watering it almost daily to make sure that the plant was well-hydrated prior to transplanting it to a larger pot and moving it to a more exposed position where it could scramble over higher supports.
As part of the watering regimen, a couple weeks back I started filling up the upper pitchers (incl. one that is partly dried) to the edge of the peristome every morning with distilled water. At first, the fact that the pitchers were emptied down to the pitchers own viscous fluid at the bottom every evening seemed fairly logical, and I put this loss down to rapid evaporation due to relatively low RH, coupled with the wide-open aspect of the pitchers' mouths, etc. However, since late last week I began to note that the rapid disappearance of this water from the pitchers could not be explained by evaporation, nor tipping, nor any small vertebrate drinking the pitcher contents, nor even my resident CP gremlins. This past weekend, when I was out in the garden for the entire day on both Saturday and Sunday and was thus able to assure myself that nothing was interfering with the pitcher processes, I started a trial to see how fast the pitchers absorbed this water and found - to my complete surprise - that all three extant uppers were draining this water over the course of several hours, in spite of the fact that we had some rainstorm late last week and RH hovered between 65 and 71% and conditions were quite still. Basically, I had to refill the pitchers every 4 hours starting at dawn to keep them with the water level above the pitchers' "waist, and inspections made even 2 hours after filling the pitchers showed a visible drop in the water level below the edge of the peristome. Pitchers of many sizes of other Nepenthes spp. grown nearby with more traditionally shaped pitchers did not lose any significant amounts of pure water added to their pitcher contents late last week as a control and some very large N. truncata pitchers that had been completely filled by pouring rain on Thursday evening showed no water loss to evporation or absorption at all.
I am well aware that slightly dehydrated Nepenthes plants and healthy but "limp" pitchers absorb pure water easily, but have never noted anything as dramatic as this. At transplant on Saturday, I found that the plant had a vigorous, very healthy looking root system and the leaves are turgid and healthy-looking and, indeed, during the entire process the plant has never looked water stressed in any way. The plant is clearly using its roots to take up some of its water needs, but it *appears* that this plant is absorbing a remarkable amount of water every day from its pitchers, and that this speed of this process continues apparently unabated after almost two weeks of topping off pitchers from 1 to 4 times daily. Since the catchment face (=upper half of the pitcher) immediately below the pitcher lid of N. lowii is very smooth and glossy even on close inspection, it may be that this region is adapted to facilitate uptake of water. Since N. lowii is known to be a true epiphyte (as opposed to also growing as a terrestrial or hemiepiphyte) on some occasions and many epiphytic plants have special adaptations to catch and store water in what can be surprisingly hostile envirnments, it may be that this sp. is *better* than many of its cogeners at this task, and absorbs the abundant rainfall caught in its wide open pitchers as a matter of course and that this function may be of near equal importance to the apparent "birds toilet bowl" role they play.
I would enjoy hearing others' experiences with this plant in this regard.
Cheerio,
Jay
just built new grow room and tons of pitcher shots!