Hormonal

With all the study on plants, and the lab going on, we've been stuffed full of information on those plants and their reproduction. Yay.

Auxins are a group of plant hormones that contribute to "growth and behavioral processes" in the life of a plant. There are four naturally-synthesized auxins in plants:

• Indole-3-Acetic Acid (IAA) -- Plays a role in embryo development, leaf formation, photo- and gravitropism, fruit development, and root development. At a molecular level, it assists with cell enlongation and cell division. Its most important role is that of a signaling molecule in the development of plant organs and the monitoring of growth. 
• 4-Chloroindole-3-Acetic Acid (4-CI-IAA) -- Although little is known about it, this hormone may be referred to as the "death hormone". It promotes the movement of plant nutrients to the seed, starving the plant and preparing the seed itself. 
• Phenylacetic Acid (PAA) -- This has similar effects to the other hormones, promoting plant growth and development. However, PAA is best known for its production of Phenylacetone, an active ingredient in Methamphetamine.   
• Indole-3-Butyric Acid (IBA) -- IBA is found often in leaves and seeds of maize and other plants. Little is known about it, but it may be converted into IAA via β-oxidation. 

Abscisic acid (ABA) is also used for many developmental processes in plants. It is known mostly for its affect on bud dormancy, as well as its affect on plant responses to environmental stress. ABA is a hormone that contributes to the abscission (cutting, shredding) of plant leaves, flowers, or seeds.

When there is an environmental abnormality, ABA takes effect. In the cold, it acts as an inhibitor to the "vascular cambium", meaning it slows plant growth in the cold. When there is little available water in the soil, it causes the leaves to reduce transpiration and conserve water.

Ethylene is a gaseous hormone that is associated with fruit ripening and the "triple response" of the plant, or the avoidance of damage to the seeds. In the protection process, the hormone affects the seed in three different steps:

• It prevents the seedling stem and root from elongating
• It induces the stem and root of the plant to become thicker.
• It bends the stem so that leaves grow horizontally. 

In addition, it also assists with the processes undertaken by the other hormone types, including abscission of leaves and fruit, flower production, budding, and opening, ripening of fruit, and "induction of femaleness in dioecious flowers". 

Most of this information is not from Wikipedia. It's all based on legitimate sources and prior knowledge.