naoki

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naoki last won the day on November 14 2016

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  1. Keith, are you interested in pH (and/or EC) of potting soil? If so, you can use regular pH and EC meter with pour-through method: http://www.greenhousegrower.com/production/crop-inputs/test-media-ph-and-ec-with-the-21-technique-pour-through-method-and-saturated-media-extract-methods/ Or are you talking about more complete tests with mineral contents, organic matters, texture etc? For those, I think most people send the samples to a lab.
  2. The ones (ORSV, CymMV) which we worry about are not air-borne virus fortunately. It is believed that they are primary transmitted by sap sharing which could be done by human or insects. Insect vector is somewhat specific to virus and insect species. Fortunately ORSV and CymMV is less likely to be transmitted by insects. But others like BYMV, CMV, CymMV etc can be transmitted by aphids. OFV can be transmited by some mites. So unless you have sap sucking insects in your grow area, neighboring plant may not be infected. According to: Inouye, N (2008). Viruses of orchids : symptoms, diagnosis, spread and control. Netherlands: Blue Bird Publishers he irrigated CymMV and/or ORSV infected Cymbidum and Cattleya and analyzed the pour-through water under the electron microscope. Also, he carefully extracted the potting media without damaging the roots. In both cases, he recovered virus. Further, he used these extracted virus on tester plants, and confirmed that they are capable of infecting. Roots die in the pot, and the virus can be exposed. ORSV is extremely stable, so the water which goes through the pot can be infectious for a long time. Most of the studies just show the potential transmission mechanisms, and it is difficult to gauge what is the main mode of the transmission. As manders suggested, human caused mechanical damage is probably a big portion of transmission, but I would consider that irrigation based transmission has a high potential to be a vector. Some people goes paranoid about virus, but it is best to consider that each plant is infected and use good sanitary measure within a reason. If you are not too familiar with plant virus, you might want to take a look at http://staugorchidsociety.org/culturepests-viruses.htm
  3. Yossu, if you have only one orchid, dipping in water is a good way. But if you share the water for multiple orchids, it is a sure way to spread virus. It is ok if they dry out quick, it is better since it is easier to control the quick-drying media than retentive ones in that way. I'm not sure what kinds of orchids, but roots get killed if they are continuously wet (due to lack of oxygen). Most people just top water with fertilizer. Many of the common ones are epiphytes. So the velamen cells, dead outer (epidermis) cells, act like sponges, and capture the water and minerals quickly. Many of us use fairly dilute fertilizer for almost all the time when you irrigate. I use around 20-30ppmN every time automatically injected to irrigation water via Dosatron. If your water is hard, this may not work. The frequency of water depends on your media and environment. If you have medium bark, and the relative humidity is around 60%, you'll be probably watering around every 3 days (assuming Phalaenopsis). If you don't know how to water, you can keep a bamboo skewer in the pot. Then you can pull it out and feel it to see if it feels cold (wet) or not. Make sure to put it back in the same spot, so you don't have to damage the roots. By doing this, you can know how long it will take for the inside of the pot become completely dry. Then you can adjust the interval. In many orchids, it would be good to water at the day it becomes completely dry or 1 day before it. After a while, you can tell how dry the pot is by weight.
  4. Utricularia blanchetii is a Brazillian terrestrial Utricularia with a limited genographic distribution (central Bahia). It seems to be ok with fairly low light (phototynthetic photon flux density, PPFD, of about 150 ┬Ámol/m^2/s). Here is the link to my Orchid Borealis blog post with a bit more info. It is interesting one of Japanese books mentions that the flower has the fragrance similar to Vanilla, but my plant doesn't have any. Does it usually have the fragrance? Utricularia blanchetii on Flickr Utricularia blanchetii on Flickr Utricularia blanchetii on Flickr Utricularia blanchetii on Flickr
  5. I wish it were the case with regard to peer-review, but in terms of nomenclature, peer-review is not required. I was pretty surprised about it. But there are some requirements such as ISSN. http://www.iapt-taxon.org/nomen/main.php?page=art29 I agree with the second point. We are trying to make the hierarchical system of classification consistent with the evolutionary history. We are still long way to go. Even though monophyly is a bit arbitrary criteria, it is a convenient one. I wouldn't call forma as a taxonomic unit, but it can be a unit in nomenclature. Note well that nomenclature isn't same as taxonomy and systematics. The later is the task of biologically classifying organisms, and the former is how you call different "groups" of organisms. However, this doesn't make the forma biologically irrelevant. In some cases, certain forms are maintained within populations for reasons. This gives us opportunities to study the evolutionary forces which are maintaining the polymorphisms (basically this is a part of population genetics, which I specialize on).
  6. pH of pour-through water is probably more telling than the pH of RO. In other words, pH of the root zone is influenced more heavily by the types of media than the water since the RO water doesn't have many ions.
  7. Thanks, Martin. I checked P-touch Editor (ver. 5.1.010) on Mac, but I couldn't find any 'chain' print option. Do you use a different software?
  8. Since you mentioned assembling, I'm assuming that you are interested in DIY grow light. I'm not familiar with European market, but don't you have digi-key, Mouser etc? When you search for parts in octopart.com, I occasionally see European vendor, so you might want to check there. I know Cutter can ship internationally. They carry both Cree and Bridgelux. They have good reputation, and their price is pretty competitive. http://www.cutter.com.au If you are going for COB, Bridgelux Vero or V series generation 7 is currently the best deal. Usually, using some cheap Chinese COB from eBay is a false economy.
  9. Don't the shoots appeared near the ground in your example produce lower pitchers? Or do they behave differently? Well, auxins, cytokinins, ethylene, and strigolacton interacts to release the lateral buds, so cytokinins are involved. But it would be interesting if the mechanism is different.
  10. I'm simply stating that the hypothesis isn't garbage as you stated here, and there is some scientific background. Sometime people make a big statement that something is bogus because they don't know enough about the topic. I didn't know if it works with Nepenthes as I mentioned (as far as I know, there isn't any research about Nepenthes apical dominance), but your anecdotal example seems to show that it does work. That's cool!
  11. Oh, I see. You are misunderstanding the transport of auxins. There are several ways to transport auxins. You are focusing on the polar (directional) transport through parenchyma cells in the cortex (cells outside of the vascular cylinder). This is relatively short-distance transportation. Auxins are required for the branching of roots as you mentioned. For this kind of long distance transport, auxins from shoots are transported to the root tips via phloem. Once they reach to the root tips, then they go through the basipetal polar transport. "Basipetal" direction is the direction toward the root-shoot junction. So auxins move toward the shoot in the root cortex. Gravity is not required for the auxin movement between parenchyma cells. There is a group of efflux proteins (pump auxins out from the cell), called PIN. PIN1 is located at the cell membrane closer to the root in each cell. This is responsible for the basipetal movement of auxins. Then another protein PIN3 seems to move around on the cell membrane. The location of PIN3 is influenced by gravity. Actual gravity sensor seems to be something called statoliths (some info in this wiki). This PIN3 mechanism is used for gravitropism in both roots and shoot. So under micro gravity, I can see that they can develop in a normal way. PIN3 will be located randomly around the cell membrane. But this doesn't go against the hypothesis that gravity can be used to release the apical dominance.
  12. Well, I don't think we completely understand the hormonal regulation of this phenomenon. But the inversion-induced release of apical dominance occurs in many plants, and it has been studied quite a bit. It has been shown that the speed of polar transport of auxins get slowed down when the shoot gets inverted (which makes sense if you think about how auxins influence gravitropism). Also, in the inverted region, it has been shown that the ethylene is produced. But it appears that there are other mechanisms involved in the release. Here is a relatively new paper about this: http://pcp.oxfordjournals.org/content/49/6/891.abstract Here is an older paper about polar transport and ethylene: http://aob.oxfordjournals.org/content/71/3/223.short So I don't think that it is a completely bogus idea, manders. I don't know if this happens with Nepenthes, though.
  13. Ignacio, I don't know about this particular model. As usual, they don't have enough specification, but it is unlikely that it is efficient. I would rather go with linear fluorescent like T8, T5, or T5HO. Plants will grow if you give enough light, but these cheap LEDs will be expensive in a long term. A lot of people goes with cheap LEDs, but it is a false economy. There is a trade-off between the initial price and the efficiency due to the property of LEDs as I mentioned in the blog posts. Also the price seems to be high. These are from China, and you can probably get the same one from eBay or AliExpress at much cheaper price. I had a similar older model long time ago, it didn't have sufficient heat management, and blue LEDs kept blowing within 6-8 months. If one of them blows, one entire row goes out. I had to replace the LEDs by soldering frequently. Hopefully, the quality has been improved.
  14. Looks very nice, manders! Richard, I don't have any experience with Genlisea, but 2 bulbs of T5HO is probably good for 70cm x 30-40cm area for the others. Maybe you can keep it about 30cm or less above the leaves. From 1 bulb, you'll get about 70 micromol/m^2/s of photosynthetic photon flux density (PPFD) (about 410 footcandle) at 30cm. So from 2, you'll be getting above 100 micromol/m^2/s. It isn't a lot for Drosera, but it will do ok. My Utricularia seems to do ok with less light than typical Drosera.
  15. Happy Thanksgiving (at least in the US)! Another DIY LED update. I made a plastic container based grow space. I used Samsung H series LED linear modules this time. This module was announced in Summer 2016, but it started to ship in October. This Samsung basically beats Philips XF-3535L (I posted about this previously) in all aspects. It has amazing efficacy (187lm/W), even higher than most COB LEDs. I haven't calculated the PAR efficiency, but I'm pretty sure there is no commercially available grow light with this high efficiency. It is a bit more expensive per light output than COB, but it is easier to assemble, and better for a small area. Also, it provides very even light distribution. It costs about $60 to cover 2-3 sq. ft. I built this for pygmy Drosera, so it is targeting relatively high-light plants. Last year, I was using much weaker light (PPFD of about 70-100 micomol/m^2/s). Surprisingly they did ok. I doubled the amount with this H-series. So we'll see how the plants respond. It takes about 1 hour to assemble. Here is the link to my Orchid Borealis blog post. This is supposed to be Drosera dichrosepala ssp. enodes from Scott River. It is with the previous weaker light.