摘要
甜高粱是重要的饲草作物,刈割能有效提高其生产潜力。为探究刈割后甜高粱的再生及体内碳水化合物的分配规律,在人工控制气候室中以水培法培养甜高粱42 d后株高约100 cm,留茬8 cm刈割,分析刈割前、刈割后7、21和35 d甜高粱株高、鲜重、叶片数、生长速率、光合作用、根系形态、结构性和非结构性碳水化合物含量变化。研究表明,刈割破坏的甜高粱株高、叶片数、茎和叶鲜重会快速恢复,在刈割后35 d已恢复至刈割前水平,甚至根系鲜重和总根长、根表面积和根尖数显著高于刈割前水平。刈割后7 d生长速率显著提高,但刈割后21和35 d又降低至刈割前的生长速率。刈割对叶片净光合速率(A)和胞间二氧化碳浓度(Ci)没有显著影响,但刈割后21 d蒸腾速率(E)和气孔导度(Gs)显著升高。甜高粱茎部蔗糖和葡萄糖含量及叶片蔗糖含量在刈割7 d后显著降低,而刈割21 d后上升。相反,叶片淀粉含量在刈割7 d后显著升高,而刈割21 d后显著降低。刈割35 d后甜高粱可溶性碳水化合物含量基本恢复至刈割前水平,甚至根部蔗糖和茎部淀粉含量更高。刈割没有显著改变甜高粱根、茎和叶中半纤维素、木质素含量,但刈割后7和21 d显著降低了根、茎和叶中纤维素含量,刈割35 d后茎和叶片纤维素含量恢复至刈割前水平。综上所述,甜高粱刈割后首先通过促进叶片淀粉积累,随后增加叶片和根系蔗糖积累以及降低纤维素含量等动态调节机制,激发刈割后植株生长速率保障地上部优先再生,其次恢复根系生长发育,协同促进甜高粱快速再生。
Sweet sorghum(Sorghum bicolor)is a vital forage crop,and cutting effectively improves its production potential.To investigate the regeneration of sweet sorghum and the distribution of carbohydrates after cutting,sweet sorghum plants were grown hydroponically for 42 days until they reached about 100 cm height in an artificially controlled climate chamber,and were then cut to a stubble height of 8 cm.Plant height,fresh weight,number of leaves,growth rate,photosynthesis,root architecture,and structural and non-structural carbohydrate contents were determined before cutting and at 7,21,and 35 days after cutting.It was found that plant height,number of leaves,and stems and leaves fresh weight of sweet sorghum quickly recovered after cutting,reaching their pre-cutting values by 35 days after cutting.The fresh weight of roots,total root length,root surface area,and number of root tips were significantly greater at 35 days after cutting than before cutting.The growth rate at 7 days after cutting was remarkably enhanced,but the growth rates at 21 and 35 days after cutting were lower than that before cutting.The net photosynthesis rate(A)and intercellular carbon dioxide concentration(Ci)of leaves were not significantly affected by cutting,whereas the transpiration rate(E)and stomatal conductance(Gs)were significantly increased at 21 days after cutting.The sucrose and glucose contents in stems and the sucrose contents in leaves of sweet sorghum were significantly decreased at 7 days after cutting,and then increased at 21 days after cutting.By contrast,starch contents in leaves were significantly increased at 7 days after cutting,and then decreased at 21 days after cutting.The soluble carbohydrate contents of sweet sorghum at 35 days after cutting had recovered to pre-cutting levels.The sucrose contents in roots and starch contents in stems were higher at 35 days after cutting than before cutting.Cutting did not significantly affect the hemicellulose and lignin contents in roots,stems,and leaves of sweet sorghum,but resulted in significantly decreased cellulose contents in roots,stems,and leaves at 7 and 21 days after cutting.The cellulose contents in stems and leaves recovered to pre-cutting levels by 35 days after cutting.Taken together,cutting sweet sorghum promotes starch accumulation in leaves,followed by an increase of sucrose accumulation in leaves and roots,and simultaneously decreases cellulose contents.Through these dynamic regulatory mechanism,cutting stimulates growth rate to ensure regeneration of shoots,and then restores root growth and development,thereby synergistically promoting the rapid regeneration of sweet sorghum.
作者
张盼
李霄霄
严发能
何远乐
白朕卿
吴佳文
ZHANG Pan;LI Xiao-xiao;YAN Fa-neng;HE Yuan-le;BAI Zhen-qing;WU Jia-wen(College of Life Sciences,Yan’an University,Yan’an 716000,China)
出处
《草业学报》
CSCD
北大核心
2024年第5期69-79,共11页
Acta Prataculturae Sinica
基金
国家自然科学基金项目(42167005,32301423)
陕西省重点研发计划(2023-YBNY-239)
延安大学博士科研启动项目(YDBK2019-17)资助。
关键词
甜高粱
刈割
再生
碳水化合物
sweet sorghum
cutting
regeneration
carbohydrate