Lowell S. Jordan

Effects of freezing to −196 °C and thawing on Setaria lutescens seeds

The effects of single and repeated freezing and thawing of Setaria lutescens seeds in liquid nitrogen were investigated. One freeze to −196 °C followed by a slow thaw, increased seed germination from 40 to 70%, but additional freeze-thaw cycles reduced germination to 30%. Using a scanning electron microscope, evidence was produced that seed coat cracking did not cause either initial increased, or subsequent reduced germination. Observations with a transmission electron microscope revealed that disruption of the integrity of lipid bodies accompanied increased damage from repeated freezing at −196 °C and thawing. Repeated freezing and thawing of seeds stored in liquid nitrogen should be done with care to avoid loss of the germplasm.

Prominent spermoderm patterns of Poaceae

Scanning electron microscopy studies of 60 genera and 118 species of the Poaceae revealed prominent spermoderm patterns. The most common patterns observed (with percent occurrence) were simple reticulate with straight walls (48.3%), simple reticulate with wavy walls (14.4%), and verrucate without pubescence (13.6%). No other pattern occurred in more than 10% of the species observed. Some genera possess common spermoderm patterns among species while others do not.

Metabolism of isopropyl carbanilate (propham) in alfalfa grown in nutrient solution

Abstract Alfalfa plants, Moapa variety, were grown in nutrient solution containing isopropylring-[14C] carbanilate (43.8 μCi/liter propham). After 8 days, 41.2% of the radioactivity initially added to the nutrient culture was recovered; 10.9% of this was from shoots, 3.4% from roots and 26.9% from nutrient medium. Nonextracted residues accounted for 23% of the radioactivity in shoots and 62% of that in roots. The parent herbicide constituted 53 and 38% of the radioactivity extracted from shoots and roots, respectively. The balance of extracted 14C was polar metabolites which were purified and subjected to enzymatic and acid hydrolysis. Four aglycones were isolated, three of which were purified by thin-layer chromatography and characterized by mass spectrometry. The principal aglycones were: isopropyl-2-hydroxycarbanilate, isopropyl-4-hydroxycarbanilate, and 1-hydroxy-2-propylcarbanilate. The fourth aglycone was not identified.

Metabolism of terbacil in orange seedlings.

Orange seedlings were cultured in aqueous solutions of 3-tert-butyl-5-chloro-6-methyluracil (terbacil and terbacil-2-14C). Radioactivity was distributed throughout the plant with the largest amount in the roots and the smallest amount in the leaves. Terbacil was metabolized to form 3-tert-butyl-5-chloro-6-hydroxymethyl uracil, which was conjugated to form aβ-glucoside as the conjugate was hydrolyzed byβ-glucosidase. Identification of the metabolite was made by infrared and mass spectrometry after isolation and purification by column and thin layer chromatography. An additional unidentified water-soluble material was accumulated in the plant. 5-chloro-uracil was not detected as a metabolite of terbacil.

Comparison ofDactylotenium Willd. andEleusine Gaertn. Spermoderm patterns

Seeds ofDactyloctenium Willd. andEleusine Gaertn. may be distinguished from each other by spermoderm patterns.Dactyloctenium seeds are transversed by ridges crossed by wavy lines forming a verrucated, reticulate pattern.Eleusine seeds have a pitted, tuberculate spermoderm pattern.

Ultracooling (to - 196 C) Effects on Barnyard Grass (Echinochloa crusgalli [L.] Beauv.) Secretory Epithelium Ultrastructure and Caryopsis Germination

Barnyard grass (Echinochloa crusgalli [L.] Beauv) florets were ultracooled 0-10 times for 5 min each time to -196 C in liquid nitrogen, thawed for 1 h in air at 24 C, and germinated Germination of caryopsis not ultracooled was 60%, while germination of caryopsis ultracooled 10 times was 99%. Changes occurred in the structure of lipid bodies of the secretory epithelium of unimbibed florets ultracooled either four or 10 times Following water imbibition, lipid bodies regained a similar form as existed prior to ultracooling Protein bodies were digested faster in the secretory epithelium of embryos ultracooled 10 times than in embryos not ultracooled