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22

Seeds are spread by many mechanisms Wind dispersal: When air currents used to spread seeds. Often these plants have evolved features to facilitate wind catching, for example dandelions. Aka, anemochory. Propulsion & bursting: When seeds are propelled from the plant in an such as in these videos. This is called Ballochory. Water: Similarly to wind ...


18

Because of a force known as geotropism - it is a reaction to gravity. The upward growth of shoots from seeds is known as negative geotropism whereas the downward growth of roots is known as positive geotropism. The act of a seed to decide which way is up, or to orient itself, is geotaxis - it detects which way is down and up, in other words, because of ...


14

In addition to the geotropism mentioned in the other answers, experiments on the ISS have shown that plants will grow oriented in a manner such that “upward” (i.e. the stem, leaves, etc.) is toward a light source, even in the absence of gravity. Of course, this depends on the plant being able to determine which way is toward the light source. Although I have ...


13

That half-life was for temperatures of 13.1ºC. In more ideal conditions, such as for temperature of −5 ºC or drier conditions, the half-life would be longer. The Wikpedia article in fact states that the seeds that were 31,000 years old were frozen under permafrost. The original article estimates that the half-life at −5 ºC (for a 30 bp fragment of mtDNA ...


9

That is a papaya seed showing vivipary, or premature sprouting. The plant is getting all the sugar it needs from the nutrients stored in the seed so it does not photosynthesize. If it were to run out, the plant would die.


7

The source paper for the article is this one: The half-life of DNA in bone: measuring decay kinetics in 158 dated fossils (available for free). The crux of their methodology is given in the abstract "By analysing mitochondrial DNA (mtDNA) from 158 radiocarbon-dated bones of the extinct New Zealand moa..." So the article you linked is talking about DNA ...


6

That might be a good experiment. I know that before planting bulbs you want to put them in the refrigerator or even the freezer sometimes. In fact this process of cold treating seeds has a name: Stratification. To paraphrase: some seeds become inactivated at higher temperatures like lettuce and delphinium. You can place the seeds in medium and put ...


6

I'd argue that this relates to species-specific strategies of seed dispersal, so the answer depends on which species you're asking about. Here's an answer for chili peppers, which I think illustrates how complex and idiosyncratic these strategies can be. As I mentioned in this answer, the seedsavers' manual Seed to Seed has great info on most plants, ...


4

It's actually not a seed pod, but rather a gall (see here or here for more info about galls). Specifically, it most likely is a gall belonging to the Oak Apple Gall Wasp (Amphibolips confluenta). You can read about this species and its gall here.


3

Selfing (aka self-fertilizing) differs from cloning. When selfing occurs, the offspring is not an exact copy of the parent. When cloning occurs, the offspring is an exact copy (except for a few mutations) of the parent. Selfing implies that an individual will produce two gametes (typically a spermatozoid and an ovule but that might be a bit more complicated)...


3

Oranges and other fruits are generally not actively made seedless. Rather, seeds may fail to develop due to either lack of fertilization (pollination) or a natural tendency. The natural production of unfertilized and thus seedless fruit is called Parthenocarpy. To quote the Scientific American article (3) mentioned by Oreotrephes: Fruit development ...


3

Most likely a member of the genus Staphylea. Since you are in Pittsburgh, PA, it's most likely Staphylea trifolia L., or an introduced species.


2

As has been pointed out, it isn't so much a question of how much gets rearranged (because everything is potentially shuffled) but is really a question of how much is lost or changed, since any genes/alleles present are going to be subject to expression. This is a simple Mendelian genetics problem, but to really answer it you need to know whether your ...


2

It makes little sense to give a percentage of the genome impacted by recombination and segregation. I think you should read about segregation and recombination and that would be clear to you why giving a percentage makes little sense. Segregation Segregation causes that the two haplogroups of the parent can be rearrange at the among chromosome level. So, ...


2

It turns out that your research question about halophytes has been asked many times before. You should learn from your predecessors... Seed germination in halophytes displays a high degree of inter- and intra-specific variability. However, Khan & Gul (2006) report that germination patterns respond to a number of environmental factors (including ...


2

A pharmacy is a public business, and they should have a scale sensitive enough to weigh seeds. They will have to let you in back to use it of course. If you show up with her and she has the seeds and she asks the manager nicely, they might let you back and help you use it. I would show up rather than call; if you show up you will see the manager / ...


2

You'd have to know the individual germination times for each family. I'm linking a table for vegetables, but it doesn't include the three plants you're looking at. A google search for each one individually shows that yes Mung does have the shortest germination time. It's a memorization question. To add to that here is a paper where they review variation ...


2

Yes, their name are "molecular marker". Every gene carrying a phenotype, quantitative or qualitative, is identified as an allele of every gene encoding for proteins. In order to identify a phenotype using just infos gained from DNA, you'll need a previous library made by these gene regions, were every polymorphism between them is associated with a phenotype....


1

These are really cool, and I am absolutely not certain of this, but I would hazard that they might be some kind of bulbil? Ferns (if I have started my ID correctly) can use them to asexually reproduce. For example the New Zealand endemic Asplenium bulbiferum grows little bulbils on the adaxial surface of its frond.


1

It sounds like your first issue is with seed germination. I am assuming you are doing a seed sterilization. You may want to try allowing them to imbibe water for about an hour after the sterilization process, and then wrapping them with aluminum foil and placing them in a fridge for a day or two. I've done this with Medicago, which is another legume. However,...


1

There's a very interesting case of mutualism between the species Homo sapiens and Oryza Sativa (also Triticum aestivum...). The humans have bred the plants to produce highly nutritious seeds, much greater then non-adapted species, and in return the humans save a small fraction of the seeds and will cultivate the plant for many generations. It goes further ...


1

This paper describes dewaxing of sunflower seeds using various solvents. As you have already shown for yourself, using hydrophilic substances such as bleach and acids do not work well in removing the waxes. Waxes are highly hydrophobic substances, and must be removed with either hydrophobic solvents (much like washing away acids with water at the emergency ...


1

The seedless grape technically has a seed, but the seed has no hard outer shell and is microscopic/invisible. These seeds aren't viable. Technically you could isolate out the seed tissue from the grape and grow it in specialized germination medium, but that process also works for any other part of the grape plant. Hooray cuttings! Certainly the seedless ...


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