Keywords: 
• botany /
• growth stage /
• plant gender /
• industrial hemp stalk /
• cellulose /
• hemicellulose /
• lignin

Abstract: Studying the influence of growth stage and plant sex on chemical compounds of industrial hemp stalks could provide a reference for renewable fiber preparation and new energy. The cellulose, hemicellulose, and lignin contents of industrial hemp stalks were tested by the high performance liquid chromatography （HPLC） and China chemical compounds analysis standard for paper making raw materials （GB/T 2677－1993）. Results showed that growth stage had a significant effect （P＜0.05） on cellulose content and lignin content of industrial hemp stalks but not on hemicellulose content. Meanwhile, plant gender significantly affected （P＜0.05） cellulose content and hemicellulose content of industrial hemp stalks but not lignin content. For the entire growth period of hemp stalk, the range of cellulose content was from 380.8 to 525.0 gkg－1, of hemicellulose content was from 174.2 to 275.5 gkg－1, and of lignin content was from 109.8 to 235.8 gkg－1. As time increased, the mass fractions of cellulose and hemicellulose increased first and then decreased （The P value of cellulose was P =0.015 2 and hemicelluloses was P=0.945 9 with SAS software）; whereas the mass fraction of lignin increased steadily （P＜0.000 1 with SAS software）. Also, synthesis of cellulose and hemicellulose was earlier than lignin. Differences between male and female gender became apparent by the 77th day of growth with cellulose （P =0.004 0 with SAS software） and lignin （P =0.123 7 with SAS software） contents of female plants being higher than male plants, and the hemicellulose content lower （P =0.001 0 with SAS software）. Reasons for differences in the chemical compounds between male and female plants will require further study.［Ch, 6 fig. 1 tab. 21 ref.］