Science Notes: Cherry Blossom Buds

SCIENCE NOTES: Autumn Cherry Blossom Bud

How much of a tree is alive, do you think? Actually only about 1%, though all of it was alive at some time or other. Wood is made up of cells, and like all living things cells will grow and multiply, and they will die. All the wood in the middle of a tree is dead. There are only two places on a tree where you find living wood. One is a thin layer just underneath the bark, and the other place is the buds. I’m talking here not about the flower buds, but the buds which are forming the new twigs and leaves. Here’s one from the autumn-flowering Cherry Blossom, seen through Clodagh’s electron microscope.

Autumn Cherry Bud fig1

In this relatively low mag picture you can appreciate the shape of the whole bud. If we zoom in a little you notice that some parts of the delicate outer leaf structures have broken, revealing several layers of living cells.

Autumn Cherry Bud fig2

The cells in a tree multiply by dividing (which sounds like a mathematical contradiction!). A tree has different types of cells to do different jobs, such as bark, roots, leaves etc. All cells start off the same, and like the stem cells in your body they differentiate into specialist types. The cells in this picture are doing the job of protecting the growing bud: quite quickly they will break up and be replaced, in fact the strange wiggly things in the picture are the remnants of earlier protective layers.

Tree Spotlight – No.1: Cherry Blossom

rows of cherry blossom trees

  • Common Name: Sweet Cherry, Wild Cherry, European Cherry
  • Scientific Name: Prunus avium
  • Distiribution: Europe and Asia
  • Tree Size: 32-65 ft (10-20 m) tall, 1-2 ft (.3-.6 m) trunk diameter

    Colour/ Appearance: Heartwood is a light pinkish brown when freshly cut, darkening to a deeper golden brown with time and upon exposure to light. Sapwood is a pale yellowish color, typically 1-2″ wide.

    Grain/ Texture: Has a fine to medium texture with close grain. The grain is usually straight or slightly wavy.

    Endgrain: Semi-ring-porous; small pores in no specific arrangement; solitary and radial multiples of 2-3; gum/deposits occasionally present; growth rings distinct due to a concentration of earlywood pores; rays visible without lens; parenchyma absent.

    Rot resistance: Heartwood is rated as being moderately durable to non-durable regarding decay resistance. Sweet Cherry is also susceptible to insect attack.

    Workability: Sweet Cherry is easy to work with both machine and hand tools. The only difficulties typically arise if the wood is being stained, as it can sometimes give blotchy results due to its fine, close grain. A sanding sealer or gel stain is recommended. Glues, turns, and finishes well.

    Odour: No characteristic odor.

    Allergies/ Toxicity: Although there have been no adverse health effects reported for Sweet Cherry, the closely related Black Cherry Black has been reported to cause respiratory effects.

    Pricing/ availability: Typically only available in Europe (or from orchards), Sweet Cherry is usually only sold in smaller sizes or as veneer. Prices should be moderate within the tree’s natural distribution.

    Sustinability: This wood species is not listed in the CITES Appendices or on the IUCN Red List of Threatened Species.

    Common Uses: Veneer, furniture, cabinetry, turned objects, musical instruments, and carvings.

    Comments: Sweet Cherry is the Old World counterpart to Black Cherry found in North America. Sweet Cherry is said to exhibit a bit more of a color contrast than Black Cherry, and it also tends to be slightly denser and stronger. However, the tree itself tends to be smaller than Prunus serotina, and does not yield the larger sizes of lumber that are available for the American species.

Tree buds SEM images

The following images from the tree bud of the Oregon Maple are really interesting. The undulating surface of the seeds are of particular interest to me. Many years ago I completed a five foot plaster sculpture inspired by a similar seed structure. We may look further at these seeds to get a closer look at the surface and interior structure.

The Oregon Maple

During the sampling process in March we also got some wonderful SEM images from the buds of the Snake Bark and the Cherry Blossom.  See below.  I love the hairy thread-like structures sticking out of the buds.

The Snake Bark – tree bud

Cherry Blossom

Science Notes: Autumn Cherry Blossom

SCIENCE NOTES: AUTUMN CHERRY BLOSSOM

These scanning electron microscope pictures show a tiny part of a flower from the autumn-flowering cherry tree. It’s one of the stamens: the small round shapes are pollen grains.

Autumn Cherry Flowers fig1.jpg

Pollen carries the reproductive cells (gametes) produced in the male parts of flowering plants. It may be annoying to those of us who suffer from hay fever and other allergic reactions to airbourne pollen, but it’s vital for many plants to spread pollen around so that the male cells will encounter female cells in the pistils of other plants.

There are many different types of pollen, and the size and shape of pollen grains varies a lot from plant to plant, so the microscopic analysis of pollen can be very useful in forensics and archaeology. This SEM image shows some of the weird and wonderful shapes of different pollens (the colours are artificial – SEM doesn’t do colour but the colour can be added later just for fun):

Autumn Cherry Flowers fig2

Source: Dartmouth Electron Microscope Facility, Dartmouth College [Public domain], via Wikimedia Commons

Bees and other insects eat pollen: for them it’s a vital food source. Lately some people have been selling bee pollen for human consumption. It probably won’t do you any harm (unless you’re allergic to it of course, in which case it might kill you) but there’s no scientific evidence that it will do you any good either, so I’m going to keep away from it.

David