图1

矢竹地下茎节间伸长的形态学观察a. an elongating rhizome of P. japonica.矢竹生长中的地下茎; b. the elongating rhizome shoot showed in (a) without sheaths; number 10-14 represents the internode from the front to the back. 图a中去鞭箨的地下茎顶端，数字10-14代表从前到后的节间号; c. cell morphology of the top part of the rhizome shoot showed in (b) (green bracket); number 1-9 represents the internode number. 图b（绿框）中地下茎顶端的细胞形态学观察,数字1-9代表节间号；d. vertical sections of rhizome shoot. The right shoot is stained by trypan blue; S1-S4 indicates the four types of internodes used for the next anatomical analysis. Green lines, pith tissues; number 11-13 indicates the internode number. 地下茎顶端的纵切面，右为经台盼蓝染色后的纵切面，S1-S4为用于后续解剖学分析的4个阶段节间，绿线示髓组织，数字11-13代表节间号。"

图2

矢竹竹鞭节间伸长生长的解剖学观察a. shoot apical meristem (SAM) (red line) of the rhizome of P. japonica. 矢竹地下茎顶端分生组织 (SAM) (红线)； SP. sheath primordium. 箨原基；b. cell morphology of the 2nd to 4th internode 第2到第4节间细胞形态； c. cell morphology of the 7th internode and the 6th node. 第7节间和第6节的细胞形态；d. cell morphology of the S2 rhizome internode. greenline. rib meristem; red arrows： vessel cells with division ability; green solid arrows： nuclei of the vessel cells; green empty arrows： fiber cells with division ability. 地下茎S2节间的细胞形态，绿线示肋状分生组织，红色箭头示具有分裂能力的维管组织，绿色实心箭头示导管细胞细胞核，空心绿色箭头示具有分裂能力的纤维细胞；e. higher magnification of the pictured. red arrows： dividing cells; red rectangle： higher magnification of a dividing cell. 图d部分扩大，红色箭头示分裂中的细胞，红色方框示放大的分裂细胞；f. cell morphologies of the S3 rhizome internode. red arrows. short parenchymal cells; red stars： long parenchymal cells. 地下茎S3节间的细胞形态，红色箭头示短细胞，红星示长细胞；g. vascular tissues of the S3 rhizome internode. red arrows： vessel cells; green solid arrows： nuclei of the vessel cells; green empty arrows： nuclei of fiber cells; red line： fiber cells; red circle： spiral pits of a vessel cell. 地下茎S3节间的维管组织，红色箭头示导管细胞，绿色实心箭头示导管细胞细胞核，绿色空心箭头示纤维细胞细胞核，红线示纤维细胞，红圈示具有螺旋纹孔的导管细胞；h. cell morphology of the S4 rhizome internode. black arrows： short parenchymal cells; red stars： long parenchymal cells; red arrows： mature vessel cells; green empty arrows： nuclei of fiber cells. 地下茎S4节间的细胞形态，黑色箭头示短细胞，红星示长细胞，红箭头示成熟的导管，绿色空心箭头示纤维细胞细胞核。"

图3

矢竹地下茎S2节间和S3节间差异表达基因概况"

图4

矢竹地下茎S2节间和S3节间与激素、RNA转录及信号转导相关的差异表达基因a. DEGs related to ABA, auxin, ethylene, GA and jasmonate were upregulated in the S3 internode, while BR and SA related DEGs were downregulated in the S3 internode. 差异表达基因中与脱落酸、生长素、乙烯、赤霉素和茉莉酸相关的基因在S3节间中上调，而与油菜素内酯和水杨酸相关的基因在S3节间中下调；b. differentially expressed transcription factors and RNA processing regulation factors between S2 and S3 internodes. S2和S3节间差异表达的转录因子和RNA调控因子；c. signaling related DEGs between S2 and S3 internode. S2和S3节间与信号转导相关的差异表达基因。"

图5

矢竹地下茎S2和S3节间与代谢、酶类相关差异表达基因DNA (a), nucleotide (b) and protein (d) synthesis related DEGs were downregulated in the S3 internode, while lipid metabolism (c), secondary metabolism (e) and enzyme families (f) were upregulated in the S3 internode. 差异表达基因中与DNA(a)、核苷酸(b)以及蛋白质合(d)成代谢相关基因在S3节间中下调，而与脂质代谢(c)、次生代谢(e)以及酶类(f)相关基因在S3节间中呈显著下调。"

图6

矢竹地下茎S2与S3节间与主要细胞过程相关的差异表达基因DEGs related to transport (a), TCA (b), metal handling (c), stress (d) and cell wall (e) were dramatically upregulated in the S3 internode, while cell?related gene (f) such as cell division and cell cycle genes were downregulated in the S3 internode. 差异表达基因中与物质运输(a)、柠檬酸循环(b)、金属代谢(c)、胁迫(d)以及细胞壁代谢相关基因均在S3节间中呈显著上调表达，而与细胞相关基因如细胞分裂与细胞周期相关基因则在S3节间中呈下调表达(f)。"