EXPLANT SIZE
The explant size has an effect on the response of the tissue. Generally, the smaller the explant, the harder it is to culture. The culture medium usually has to have additional components. The larger explant probably contain more nutrient reseves and plant growth regulators to sustain the culture. Tran Thah Van (1997) published an intereting report on thin epidermal slice of tobacco stem tissue and varying morphogenetic potential depending on whether the explant is taken from the base, middle, or top of the stem. Plant have different hormonal balances throughout the plant and on the location of the explant, the explant can have different endogenous level of plant growth regulators. Internal different in hormone balance in the tissue can result in varying in vitro responses.