Figure 2.—The tomato flower. Varieties differ in protrusion of pistil beyond the stamen column. If style is too short, pollination may fail; also, if too long. A long pistil increases danger of damage from heat and drying out.
Hot, dry winds often damage floral parts and the blossoms drop without setting fruit.
Smith[3] has shown that pollen grains germinate best at 85° F., almost as well at 70° F., poorly at 50° F. and very [poorly ]at 100° F.
Figure 3.—Long section of tomato flower.
The flowers of the tomato are borne in simple racemes or, in some varieties, in compound clusters. The flowers are normally on the plan of 5 but cultivated varieties may have six or eight sepals and petals. Sepals are narrow and may be as much as an inch long. Petals are united at the base. Stamens are united by the anthers surrounding the style and stigma. The ovary or little tomato is above the calyx but, as it grows, it carries corolla and stamens outward until they, with stigma and style, drop off. Length of style is a fairly important character in its bearing on pollination and on susceptibility to heat and wind injury.
Seedless Fruits
Recent experiments by several workers have demonstrated the possibilities of inducing development of fruits without pollination (parthenocarpy) by means of certain chemical compounds, notably indolebutyric acid, although others are effective.[4] This method yields seedless fruits and promises to be of value in insuring a yield of fruits under conditions unfavorable for natural setting.