Mathan D.
The general appearance of heterozygous lanceolate (TGC6: 19, 1956) suggested that it differed from normal in having a disturbed hormone balance.
In order to test this assumption, a series of preliminary experiments was carried out.
(1) Indole-3 acetic acid. Spraying heterozygous lanceolate seedling once a day for a period of three weeks with either a 5 or a 10 ppm aqueous solution of indole-3 acetic acid did not result in any appreciable modification in leaf shape.
(2) Gibberellic acid. After spraying a 10 ppm aqueous solution of gibberellic acid on young lanceolate seedlings once every two days for 4 weeks the mature leaves were narrow and resembled the homozygous lanceolate obtained from the (lanceolate x) broad x lanceolate. Similar applications on broad, potato and normal seedlings gave mature leaves that had larger than usual terminal lobes and a decreased number of secondary leaflets. In all cases, including lanceolate, gibberellic acid produced an increase in plant height as measured from the cotyledons up to the first inflorescence. The increase in height was due both to an increase in the number of leaf primordia and also to a greater internode length.
(3) Diffusate from germinating seeds. Seeds from normal plants were germinated in distilated water. After three days the water, which contained diffusable substances from the germinating seeds was removed and distilled water was again added. This procedure was repeated daily for a period of three weeks.
The diffusate was sprayed once a day for a period of one week on heterozygous lanceolate plants. There was a noticeable increase in the number of secondary leaflets. That is, there was a tendency for mature lanceolate leaves to be more normal.
At the end of three weeks the normal seeds failed to complete germination. The roots developed almost at the normal rate and the hypocotyl elongated slightly but the cotyledons never emerged from the seed coat nor did they show any sign of growth.