Freesia Hybrida Research Articles

Influence of Alternating Day and Night Temperatures on Flowering of Freesia hybrida1

Abstract Plants of Freesia hybrida Bailey ‘Moya’, grown from corms and ‘Royal Crown’ from seed flowered when the temperature was 13°C continuously or with 13° during an 8 hour light span or with 13° during a 16 hour dark span both of which were alternated with 24°. Flower quality was poor but marketable on plants treated a 13° light or dark temperature alternated with 24°. Results suggest that the commercial production season could be extended into warm seasons by maintaining 8 hours of inductive temperature (13°) in greenhouses or coolers. Flowering or corm filling did not occur at continuous 24°.

ROOT CONTRACTION IN FREESIA (IRIDACEAE)

The contractile roots of the horticultural variety Freesia hybrida Bailey (Iridaceae) were determined to contract via a growth/collapse mechanism. Contraction is initiated by a radial growth of middle and outer cortical parenchyma cells which is morphologically evident by an expanded diameter of the root. No concomitant decrease in length of the actively growing cells was observed. Shortening of the root is caused by axial tension produced by the radial growth of cells contiguous with nonexpanded cells distally. Centripetal collapse of expanded cells, coupled with passive shortening of inner cortical parenchyma and stelar tissues, releases axial tension slowly, returning the shortened root to equilibrium. Inner cortical parenchyma cells shorten in an accordion‐like manner facilitated by partial dissolution of middle lamellar material.

Flower Production of Freesia hybrida Seedlings under Night Interruption Lighting and Short Day Influence1

Abstract Flowering dates of freesias (Freesia hybrida Bailey) sown at monthly intervals varied according to monthly temperature fluctuations over a 2-year period. Seeds germinated from April to June reached anthesis from December to March. April through June seeding dates were acceptable for obtaining optimal flower production and quality in Minnesota, but these plants were slower to flower than those seeded from July through November. Night interruptions by incandescent light hastened flowering, but flower quality was poorer than from plants grown under natural days. Short days and night interruptions using BCJ-Ruby incandescent lamps had no influence on flowering date.

Effects of Hydrofhiosilicic Acid, Superphosphate, and Treblesuperphosphate Soil Applications on Leaf Injury in Freesia hybrida1

Abstract Necrotic areas along leaf margins and at leaf tips were observed on Freesia hybrida Bailey when an aqueous application of hydrofhiosilicic acid (H2SiF6) was added to the growing medium. Similar foliar symptoms occurred with the addition of superphosphate or treblesuperphosphate which contains 1.0–1.6% F as a contaminant. Tissue fluoride levels increased when H2SiF6, superphosphate or treblesuperphosphate was added to the soil.