Submitted to: HortScience
Publication Type: Peer reviewed journal
Publication Acceptance Date: 5/27/2009
Publication Date: 8/1/2009
Citation: Chen, G.Q., Vang, L., Lin, J.T. 2009. Seed Development in Lesquerellar fendleri (L.). HortScience. 44:1415-1418. Interpretive Summary: A conventional source of hydroxyl fatty acid is from castor oil which contains 90% ricinoleate. Ricinoleate and its derivatives are used as raw materials for numerous industrial products, such as lubricants, plasticizers and bio-diesel. However, the production of castor oil is hampered by the presence of the toxin ricin and hyper-allergenic 2S albumins in its seed. We are developing a safe source of castor oil by genetic engineering Lesquerella fendleri to produce ricinoleate. Assessment of the seed development is essential in seed selection and comparison in various seed development studies. Yet, the precise seed development stages in L. fendleri have not been established. In this manuscript, we investigated the morphological (seed size and color), physiological (fresh weight, dry weight and germination) and biochemical (storage oil and protein) changes from fertilization to desiccation
Technical Abstract: The morphological, physiological and biochemical changes during seed development of Lesquerella fendleri was investigated from 7 days after pollination (DAP) to desiccation. The entire course of seed development lasted about 49 days and it can be divided to seven continuous stages (I to VII). During the early stages (I to III, 7 to 21 DAP), seeds grew rapidly, showing dramatic increase in size and fresh weight. They contained about 75% water content. When seeds entering mid-maturation stages (IV to V, 28 to 35 DAP), storage lipids, proteins and other dry weights accumulated at maximum rates. The accumulation curves followed a sigmoidal pattern during seed development. Due to water loss, fresh weight dropped significantly when seeds progressed to late-maturation/desiccation stages (VI to VII, 42 to 49 DAP). The size of seed decreased slightly and color changed from green to orange-brown. Profile of seed proteins was also analyzed using SDS-PAGE. Proteins with high molecular weights were prominent in developing seeds at early stages (I to III). Upon stage IV (28 DAP), proteins with low molecular weights appeared while the high molecular weight proteins faded. These low molecular weight proteins became predominant throughout the remaining stages of seed development. 47% of freshly harvested seeds at 35 DAP were able to germinate. The germination rate rose to a maximum of 95% at 42 DAP. The relationships among seed morphology, reserve synthesis and germination are discussed.