Increased Germination through Pregermination Treatments of Chinese Pistache Seeds
1994; Wiley; Volume: 7; Issue: 1 Linguagem: Inglês
10.2134/jpa1994.0116
ISSN2689-4114
Autores Tópico(s)Plant Reproductive Biology
ResumoChinese pistache (Pistacia chinensis Bunge.) trees are valued for their fall color and pest resistance in landscape plantings; however, there are few cultivars of this species because of difficulties in propagation. Chinese pistache is primarily propagated by seeds. The objectives of these studies were (i) to determine the effect of the source plant on seed germination, and (ii) to determine the effect of scarification, stratification, and GA3 (3-0-β-D-glucopyranosyl ether; Sigma Chemical Co., St. Louis, MO) treatments on germination percentage and rate. Fruits of Chinese pistache were collected from four parent trees in 1988 and the pericarp was removed from half the seeds from each tree. Seeds with and without pericarp present received 0, 30, or 60 d of stratification at 36 °F or were treated with 1000 ppm GA3. In 1991, seeds were collected from two of the same trees and two different trees and the pericarp was removed from all seeds. Half of the seeds from each tree were treated with concentrated sulfuric acid, Both treated and non-treated seeds received 0, 30, or 60 d stratification at 36 °F or 1000 ppm GA3. Removal of the pericarp was necessary for seed germination regardless of other treatments provided. The germination percentage and rate depended on the parent plant from which the seeds were collected. Scarification and stratification generally increased germination percentage and germination rate. GA3 increased germination percentage in seeds from some parent plants, but was not as effective as stratification. Research Question Chinese pistache is an ornamental tree valued for fall color, pest resistance, and adaptability to heat, drought, and alkaline soils. Most nurserymen propagating Chinese pistache gather seeds from the same parent plants yearly. Finding an appropriate parent plant, however, can be challenging since Chinese pistache is dioecious, alternate bearing, and fruit quantities vary by tree. This study was conducted to determine whether increased germination percentages and more uniform emergence times could be achieved by choice of maternal parent, and pregermination treatments consisting of scarification, stratification, and gibberellic acid (GA3). Literature Summary Currently, few cultivars of Chinese pistache are available because it is difficult to propagate vegetatively. Cold, moist stratification increases germination percentage, but is time consuming. Seed germination of other species has been increased with scarification, and applications of GA3 have been shown to substitute for stratification in some cases. Successful use of GA3 offers the advantage of an increased germination rate and a potentially shorter production cycle since stratification time can be reduced or eliminated. Study Description Two experiments were conducted. In 1988, seeds were collected from four trees in Stillwater, OK. Seeds with or without the pericarp intact were stratified at 36 °F for 0, 30, or 60 d in moist peat moss or soaked in 1000 ppm GA3 for 16 h prior to planting. In 1989, seeds were collected from two of the same trees in Stillwater and two trees in Wichita, KS. The pericarp was removed from all seeds and half the seeds from each tree were scarified in concentrated sulfuric acid. Scarified and non-scarified seeds were then stratified at 36 °F for 0, 30, and 60 d in moist peat moss or soaked in 1000 ppm GA3 for 16 h prior to planting. Germination percentage and time were determined for seeds in all treatments each year. Applied Question Can pregermination treatments increase germination percentage and rate of Chinese pistache seeds? Removal of the pericarp was necessary for germination regardless of other pregermination treatments. Scarification and stratification generally increased germination percentage and rate, particularly in seeds of trees which normally had low germination rates when pregermination treatments were not used (Fig. 1 and 2). Applications of GA3 at 1000 ppm were not as effective as cold stratification at increasing germination percentage and rate, and its use on Chinese pistache appears limited. Recommendations The pericarp should be removed from all Chinese pistache seeds immediately after harvest, then the seeds should be stratified for 60 d. Ten minutes of scarification in concentrated sulfuric acid prior to stratification can further increase germination percentage and rate. Due to variability in germination characteristics of seeds from different parent plants and seasonal variability, seedlots from different plants and harvest times should be kept separate. Figure 1Open in figure viewerPowerPoint Effect of 0, 30, or 60 d of stratification or a 24 h treatment with 1000 ppm of GA3 on percentage germination and time to 50% germination of seeds with pericarp removed of four Chinese pistache trees. * indicates a significant difference at P = 0.05 in percentage germination or number of days to 50% germination between the stratification treatment indicated and GA treatment within maternal parent. Figure 2Open in figure viewerPowerPoint Effect of 0, 30, or 60 d of stratification or a 24 h treatment with 1000 ppm of GA3 on percentage germination and time to 50% germination of nonscarified (A) and scarified (B) seeds of four Chinese pistache trees. * indicates a significant difference at P = 0.05 in percentage germination or number of days to 50% germination between the stratification treatment indicated and GFA treatment within maternal parent.
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