Current state of my plants...critiques welcome and guidance needed

[jesscorine]

Thanks everyone! It was going to be my project today to do what I can with what I have, as far as downsizing...but I threw out my back carrying my daughter to my son's busstop at noon. Maybe during the monsoon tomorrow

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[jesscorine]

I spent some time digging out the phal in the last two pics. The roots are SOO plump and stiff! It took a bit of provocation but I got it into a slightly smaller ceramic pot with bark only. It was very difficult to get the bark into the "cage" of roots. The moss wasn't too decayed either, but it was very wet even without a recent watering. Should I pack a bit of moss into the root "cage" to keep a little moisture in there?

[The Orchid Boy]

You could, but it is not needed. Orchids prefer to dry out fast and be watered often rather than the other way around.

I learned something new today, most orchids are CAM plants. I knew they had the features but never really knew the technical name. Ok, done babbling. Just had to say that.

[jesscorine]

Originally Posted by The Orchid Boy

I learned something new today, most orchids are CAM plants. I knew they had the features but never really knew the technical name. Ok, done babbling. Just had to say that.

what does that mean?

[WhiteRabbit]

Actually, an air pocket in the root mass can be a good thing. I try to create that by using a small over-turned net pot int the bottom center of the pot I am repotting into, or tuck some styrofoam into the root mass. Makes for more evenly drying of the media, and the roots like the air.

[King_of_orchid_growing:)]

Originally Posted by The Orchid Boy

You could, but it is not needed. Orchids prefer to dry out fast and be watered often rather than the other way around.

I learned something new today, most orchids are CAM plants. I knew they had the features but never really knew the technical name. Ok, done babbling. Just had to say that.

Originally Posted by jesscorine

what does that mean?

The short story is that CAM is a type of carbon fixation pathway (edited to reflect what it really is), that plants utilize. It's an acronym and stands for Crassulacean Acid Metabolism.

Most cacti and succulents fall within the category of using this type [CAM] of photorespiration.

Let's just say I spared you from roughly a whole week's worth of botany lectures about this subject matter.

[Discus]

Basically what CAM does for plants is twofold - 1) it exploits the slightly elevated levels of CO2 in the air at night by effectively binding up CO2 into something called Malic Acid. 2) This means that most CAM plants only really open their stomata (small holes in the leaves through which they "breathe") at night; this is valuable for most orchids, because you lose less water at night (it's cooler and often more humid) - and you can imagine if you're an epiphyte or lithophyte with uncertain access to water, or a succulent growing in an arid region, saving water is a high priority.

During the day, the CO2 bound up in the Malic Acid is released and used in photosynthesis. (If you're wondering about the name, the metabolism was first discovered in a group called the Crassulaceae, a big family of succulent plants- some of which live in alpine environments, where the lack of water is not so much from desert conditions, but from it being frozen solid!). (Also, somewhat confusingly, note that you might expect they'd be working with something named "crassulacean acid", but the name refers to the acid metabolism in crassulaceae, rather than an organic acid first discovered in that group and named for it, which could of course be called "crassulacean acid" - I made this mistake when I first heard of it!)

Strictly speaking, it's not photorespiration at all, but a carbon fixation pathway. In fact, because it increases the intracellular concentration of CO2, it helps to prevent the need photorespiration (which is bad) driven by RuBisCO's deep flaw. It is probably the least efficient (because it's about as likely to catalyse the "wrong" reaction (adding oxygen) as the "right" (fixing CO2) one, and acts very slowly), but arguably the most important enzyme (and possibly the most common enzyme) on the planet.

If you want more detail without ending up in University level details, the wikipedia page gives a fair overview. Crassulacean acid metabolism - Wikipedia, the free encyclopedia

Most grasses use a somewhat similar idea, called C4 metabolism. "Normal" carbon fixation in plants is C3.

Unless you've done a fair amount of fairly advanced biology, diagrams like this are probably complete nonsense, but they do show (in some detail) what is going on:

Even this diagram is simplified, as it doesn't show things like the ATP and NADH "used up" in driving the process. (ATP and NADH are like the batteries of cellular metabolism, they are used to provide "energy" for reactions that require it; cellular respiration generates ATP and NADH). Of course, using more of these to fix carbon means they can't be used elsewhere, so this is "expensive", so not all plants use these "tricks" (C4 and CAM).

[King_of_orchid_growing:)]

Originally Posted by Discus

Basically what CAM does for plants is twofold - 1) it exploits the slightly elevated levels of CO2 in the air at night by effectively binding up CO2 into something called Malic Acid. 2) This means that most CAM plants only really open their stomata (small holes in the leaves through which they "breathe") at night; this is valuable for most orchids, because you lose less water at night (it's cooler and often more humid) - and you can imagine if you're an epiphyte or lithophyte with uncertain access to water, or a succulent growing in an arid region, saving water is a high priority.

During the day, the CO2 bound up in the Malic Acid is released and used in photosynthesis. (If you're wondering about the name, the metabolism was first discovered in a group called the Crassulaceae, a big family of succulent plants- some of which live in alpine environments, where the lack of water is not so much from desert conditions, but from it being frozen solid!). (Also, somewhat confusingly, note that you might expect they'd be working with something named "crassulacean acid", but the name refers to the acid metabolism in crassulaceae, rather than an organic acid first discovered in that group and named for it, which could of course be called "crassulacean acid" - I made this mistake when I first heard of it!)

Strictly speaking, it's not photorespiration at all, but a carbon fixation pathway. In fact, because it increases the intracellular concentration of CO2, it helps to prevent the need photorespiration (which is bad) driven by RuBisCO's deep flaw. It is probably the least efficient (because it's about as likely to catalyse the "wrong" reaction (adding oxygen) as the "right" (fixing CO2) one, and acts very slowly), but arguably the most important enzyme (and possibly the most common enzyme) on the planet.

If you want more detail without ending up in University level details, the wikipedia page gives a fair overview. Crassulacean acid metabolism - Wikipedia, the free encyclopedia

Most grasses use a somewhat similar idea, called C4 metabolism. "Normal" carbon fixation in plants is C3.

Unless you've done a fair amount of fairly advanced biology, diagrams like this are probably complete nonsense, but they do show (in some detail) what is going on:

Even this diagram is simplified, as it doesn't show things like the ATP and NADH "used up" in driving the process. (ATP and NADH are like the batteries of cellular metabolism, they are used to provide "energy" for reactions that require it; cellular respiration generates ATP and NADH). Of course, using more of these to fix carbon means they can't be used elsewhere, so this is "expensive", so not all plants use these "tricks" (C4 and CAM).

I gotta take a refresher's course!

---------- Post added at 08:17 AM ---------- Previous post was at 08:09 AM ----------

Btw, just so you know what plants categorized as Crassulaceae are. This is the most common example:

http://www.bcss-liverpool.pwp.blueyo...rborescens.jpg

You may know them as plants in the genus Crassula.