Indian ricegrass [Olyzopsis hy#nt?noties (Roem. and Schuit.) Ricker] is an excellent native species for revegetation of coal and oil shale sites. However, inadequate germination due to a high seed dormancy results in poor stand development and limits its use. This paper presents the results of a series of experiments attempting to reduce the dormancy by weakening the lemma and paiea by scarification of the seed covering. Four treatments (three mechanical nnd one concentrated sulfuric acid) were examined, alone and in combination with gibberellic acid. Three ages of seed were tested in the greenhouse, the laboratory and the field. Concentrated sulfuric acid and a modified commercial scarifier most effectively increased germination in the greenhouse; gibbereilic acid enhanced germination of the younger, fresher seeds in this environment. A rubbing machine improved emergence in the tieid more than the other treatments. It was, however, only a modest improvement. Concentrated sulfuric acid decreased field emergence for ail 3 ages of seed. Germination studies in the laboratory indicated that none of the treatments increased mortality.
Blue grama [Bouteloua grads (H.B.K.) Lag. ex Steud.] has been diicult to establish from seed on disturbed areas of the Central Plains. The objective of this study was to investigate the relationship of caryopsis weight, planting depth, and genetic variability on seedling emergence of blue grama. Two experiments were conducted in the greenhouse under favorable moisture conditions with 3 accessions and various combinations of caryopsis weight and planting depth. Measurements included rate of germination and emergence as an index, percentage emergence, shoot length, shoot weight, seminal root length, coleoptile length, subcoleoptile internode length and weight, adventitious root weight, and longest adventitious root length. The length of the subcoleoptile internode increased in response to greater planting depth but weight per unit length deereased. If this indicates a decrease in internode diameter it could decrease the rate of water transport through the internode. Deep plantings were not advantageous to emergence or seedling growth under favorable soil moisture conditions and caused a delay in emergence and decreased percentage emergence, shoot weight, and adventitious root weight. High crryopsisweight was associated with an increase in emergence, weight per unit length of the subcoleoptile internode, coleoptile length, shoot weight, and adventitious root weight. Therefore, high caryopsis weight is advantageous in the deep plnnting of blue grama seeds and allows seeds to be planted deeper to take advantage of moisture for germination and emergence.
Indian ricegrass [Oryzopsis hymenoides (Roem. & Schult.) Ricker] has been of interest for revegetation of western mine lands, however, high seed dormancy restricts stand establishment. Breeding to improve Indian ricegrass is hampered by this inherent dormancy, often as high as 98%. Scarification to break dormancy using sulfuric acid has been successful but reduction of viability has occurred. This study examined whether the number of seeds damaged by scarification was related to the thickness of the indurate lemma possessed by Indian ricegrass. Twelve strains and cultivars of Indian ricegrass were examined with a range in lemma thickness of 42 to 76 μm. They differed significantly for this trait, which was not affected by environment. Acid scarification treatments of 20, 30, and 40 rain were followed by water rinses. Viability before and after scarification was determined by tetrazolium tests. Lemma thickness had a significant protectiveffect on seed viability after scarification for all three scarification durations. Coefficients of determination (R2) values were 0.56, 0.75, and 0.79 for 20, 30, and 40 min time, respectively. These results indicate that lemma thickness can be utilized to determine proper scarification duration to minimize seed damage while maximizing germination, resulting in uniform stand establishment and evaluation of Indian ricegrass germplasm.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.