http://hdl.handle.net/10150/297346 Wed, 22 Apr 2026 12:42:17 GMT 2026-04-22T12:42:17Z http://hdl.handle.net/10150/556691 Lonesome Valley: Rio Huasco, River of the Atacama Petrie, Jeffrey M. Tue, 01 Dec 2009 00:00:00 GMT http://hdl.handle.net/10150/556691 2009-12-01T00:00:00Z http://hdl.handle.net/10150/556666 Effect of Pre-germination Treatments on Seed Germination of Helianthemum lippii (L.) Dum.Cours. Zaman, S.; Padmesh, S.; Tawfiq, H. Helianthemum lippii (L.) Dum. Cours. is a perennial shrubby plant 10-45 cm tall that belongs to the family Cistaceae. The effects of pretreatments on germination of Helianthemum lippii provide information regarding germination requirements of this species, which could be used for conservation studies. Five different pretreatment were applied to enhance seed germination. Scarification followed by germination at 6 different constant temperatures (10, 15, 20, 25, 30 and 35°C) with continuous light or dark, Scarification followed by GA3 soaking (100, 250,500,750 and 1000 ppm), Heat and moist stratification (only intact seeds), KNO₃ and H₃BO₃ soaking (only intact seeds). The results obtained from this study indicate that germination in H. lippii was promoted by scarification. Scarification of seeds resulted in high germination while increasing germination temperature (35°C) decreased the germination of scarified seeds. Exposure to light and dark had no effect on germination. Heat stratification, cold stratification, KNO₃ and H₃BO₃ treatments were ineffective in increasing germination of H.lippii seeds. Scarification yielded maximum germination without soaking in GA₃ It increased the germination of Helianthemum lippii seeds from 1 to 99%. Increase in GA₃ concentration decreased the germination of this species. Scarification succeeded in breaking dormancy of H.lippii seeds suggesting that this species exhibits seed coat dormancy and in nature it may happen due to the abrasion of seed coat by sand particles or other biotic and abiotic factors. Tue, 01 Dec 2009 00:00:00 GMT http://hdl.handle.net/10150/556666 2009-12-01T00:00:00Z http://hdl.handle.net/10150/556665 World Vegetation in Relation to the Boyce Thompson Southwest Arboretum Shantz, Homer L. Tue, 01 Dec 2009 00:00:00 GMT http://hdl.handle.net/10150/556665 2009-12-01T00:00:00Z http://hdl.handle.net/10150/556664 Dedication of Boyce Thompson Arboretum April 1929 Crider, Franklin J. Tue, 01 Dec 2009 00:00:00 GMT http://hdl.handle.net/10150/556664 2009-12-01T00:00:00Z