Photosynthesis is the process plants use to make wood from air and light. Although that sounds suspiciously similar to magic, it's not that hard to understand. Solar cells after all, convert light to electricity - or rather, transform the energy of light into more energetic electrons. The difference for a plant is that it needs to store the energy as chemicals, just like batteries.

Stage One
As with respiration, the 'machine' which caries out the conversion is a membrane studded with proteins. This uses membrane potential to drive synthesis of ATP, and the absorbed light drives the formation of the membrane potential. This doesn't sound like the formula above, but this is only stage one - harnessing the light. This is where the oxygen gets made from water in a process called photolysis (water-splitting)1:

ADP + Pi + H2O --light--> O2 + ATP

So photolysis stores light energy at the expense of water - which is part of the reason plants need so much water. Well, maybe this is negligible compared to evapotranspiration, but water is essential. Actually, there are organisms that use other reducing agents (H2S - Hydrogen Sulphide for example) and they produce the corresponding oxidised product (elemental sulphur, for example).

Stage Two
Now the plant (or micro-organism) is free to use the generated ATP2 to make sugars; the sugars can then be made into almost anything else - carbohydrates, amino acids' skeletons, fats...This is the 'synthesis' part of the process, and it starts with carbon dioxide - a gas found in the air at a fraction of a percent3. An extremely important protein called RUBISCO uses the CO2 to make a 5-carbon sugar into a six carbon sugar4. In other words it 'fixes' the carbon into a larger molecule. The ATP produced in stage one provides the energy (ultimately from the sunlight) to convert these sugars into a common intermediate called GAP (glyceraldehyde-3-phosphate) which is also an intermediate in glycolysis. The whole fixation process is cyclical, in that the 5-Carbon sugar (RuBP) has to be regenerated to be able to fix more carbon. The wheels of this conveyor belt that brings carbon into the plant is turned by light and greased by ATP2.

1: The stoichiometry isn't right, but it gives the idea.
2 : And NAD(P)H, but that's just detail :)
3: For the moment...
4 : Which then breaks down immediately to two 3-C sugars.

Photosynthesis is an abstract strategy game from Blue Orange Games (the publisher of kingdomino). Designed by Hjalmar Hach and illustrated by Sabrina Miramon, Photosynthesis is a beautifully crafted offering with elegant, thematic rules and abstract, cut-throat gameplay. Game size is 2-4 players, recommended ages 8+, with a beginner and advanced rule set to tune the complexity of game play.

Photosynthesis is packaged within a cleverly cut square box of durable corrugate. Featuring a single highlighted tree amidst a sprawling forest, an orchestra of greens and yellows is center stage for the exterior artwork. The lid fits exactly right - there is a deliberate tension whilst removing the lid from the box, but the weight of pieces/board is enough to permit the two separate. The game board within is two pieces - one rectangular board with a hexagonal play area where spaces go from sandy river-side to meadowy grass to deep and loamy soils, and one angular sun board which rests in sequence at the six vertices of the hexagonal playing area. There are four player cards (bank, rules, and scoring) with their own sun point tokens, small/medium/large trees, and seeds. The individual forests are differentiated by both color (red, blue, yellow, and green) and species (oak, conifer, maple, and linden). The trees themselves are where the artist ran wild. Each tree is composed of two perpendicularly joined dye-cut cardboard pieces. The edges are sound, and the trees join without being forced, but also have a clear mechanical tension - like the lid. Within the roots and branches of the tree are little pieces of novelty art which illustrate a tremendous attention to detail. A squirrel here, a robin's nest there. A bluebird on this branch, a rabbit sitting upon that root. Thematic with the biomes from whence they came, the artwork is breathtaking and a wonderful supplement to overall enjoyment of this game.

The objective of Photosynthesis is to collect the most point tiles. You collect a point tile by harvesting your largest tree - and are rewarded more points both by harvesting before other players, and by harvesting a tree nearer the center of the board. You grow a large tree from a medium tree, you grow a medium tree from a small tree, and you grow a small tree from a seed. All of these activities (as well as "buying" these pieces from your bank to a "to be placed" area) are funded by sun points. Each player collects sun points as the sun rotates around the hexagonal board and the players calculate which trees are basking and which are shaded.

To calculate how many sun points you've earned for a round, you need only follow the directional arrows on the "sun" piece (which sits at one vertex, but spans two edges of the hexagonal board) until you hit a tree. If there is nothing between the sun and your tree, you earn sun points - bigger trees earn more sun points (small - 1, medium - 2, large - 3). As a bonus, your tree will now cast shade for a respective number of spaces directly behind it (away from the sun), and a tree of equal size which rests in the shade of your tree will collect no sun points. If your medium tree is on the edge of the board where the sun is, your first opponent has a medium tree one space behind you, and your second opponent has a large tree one space behind that: you get 2 sun points, the first opponent gets 0 sun points, and the second opponent gets three sun points (because it is taller than the shadow. Makes sense, don't it?).

The game builds very naturally. It costs more sun points to get bigger/better trees out of your bank. It costs more sun points to upgrade from a medium to large tree than it does to upgrade from a seed to a small tree. The small/medium/large trees work very well around the numbers 1/2/3 - it is the number of sun points they collect (unobstructed), it is the number of linear spaces they cast a shadow (against equal or smaller trees), and it is the number of linear spaces they can drop a seed within. Simple. Natural. Organic.

Projecting future cashflows with imperfect information is just part of the tantalizing layers of depth this abstract strategy game holds. After each player collects their sun points (perfect information) they will then, one by one, execute all actions they wish to for that particular turn. The player who goes first will know how many sun points their opponents have, and they will know which way the sun will shine on the next turn. The player who goes first will not know what their opponents plan to do during their turn (imperfect information aspect), which causes huge swings in future economy of sun points. It is important to note that sun points do not expire, and may be carried over turn by turn, but there is a maximum to how many you can accrue at any on time. Additionally, during your turn, a space can only be used once. Thus, if you harvest your big tree from the very middle space for a maximum point tile, then you cannot drop a seed on that same middle space during the same turn. But the next player, if they are close enough, can. This goes on for three rounds (the sun completing a full circuit is one round), and then the player with the most point tiles (added together) is the winner.

The board of Photosynthesis is a hexagon transcribing four concentric rings of circles. There is one center circle, surrounded by six circles, surrounded by twelve circles, surrounded by eighteen circles. The outermost ring (where you must place both your initial trees) has six vertices, which represent the six 'turn' positions of the sun for each round of the game. My preferred nomenclature, illustrated below and employed in the strategy nodes, will be {Vertex; Ring; Slice} where the vertices are distinguished by Greek alphabet letters from start-position clockwise, the Ring are distinguished numerically outside in, and the Slice representing a non-axial position in a clockwise fashion by English alphabet letters. The Center circle shall be represented by ω as that is where the six axes converge, and the six vertex positions would be signified by α1A, β1A, γ1A, δ1A, ε1A, and ζ1A respectively (the game board is marked with a small sun icon at the vertex from where the game begins - this is the α vertex for my positional notes).

ζ1C α1B
ζ1B α2A α1C
ζ1A ζ2B α2B β1A
ζ2A α3A β2A
ε1C ζ3A β3A β1B
ε2B ω β2B
ε1B ε3A γ3A β1C
ε2A δ3A γ2A
ε1A δ2B γ2B γ1A
δ1C δ2A γ1B
δ1B γ1C

Strategy/Analysis: Zero Player Strategy, Initial Placements, Opening, Midgame, Endgame, Advanced Rules

IronNoder 2018: 05/30

Pho`to*syn"the*sis (?), n. (Plant Physiol.)

The process of constructive metabolism by which carbohydrates are formed from water vapor and the carbon dioxide of the air in the chlorophyll-containing tissues of plants exposed to the action of light. It was formerly called assimilation, but this is now commonly used as in animal physiology. The details of the process are not yet clearly known. Baeyer's theory is that the carbon dioxide is reduced to carbon monoxide, which, uniting with the hydrogen of the water in the cell, produces formaldehyde, the latter forming various sugars through polymerization. Vines suggests that the carbohydrates are secretion products of the chloroplasts, derived from decomposition of previously formed proteids. The food substances are usually quickly translocated, those that accumulate being changed to starch, which appears in the cells almost simultaneously with the sugars. The chloroplasts perform photosynthesis only in light and within a certain range of temperature, varying according to climate. This is the only way in which a plant is able to organize carbohydrates. All plants without a chlorophyll apparatus, as the fungi, must be parasitic or saprophytic. -- Pho`to*syn*thet"ic (#), a. -- Pho`to*syn*thet"ic*al*ly (#), adv.


© Webster 1913

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