Table 4. Principal component analysis (PCA) results for anatomical and chemical properties of Broussonetia kazinoki bast fibers

Variable	PC1	PC2	PC3
Fiber length (mm)	–0.016858278	0.513223015	–0.182467238
Fiber width (μm)	–0.271223934	0.407395635	0.325309874
Lumen width (μm)	–0.417922033	0.238293348	0.249769811
Cell wall thickness (μm)	0.037952502	0.501273756	0.313361045
RR	0.461351362	0.156109926	–0.00094696
AR	0.122443303	0.361258576	–0.370125671
FC	–0.4618796	–0.155757413	0.00134752
RC	0.462019965	0.155573008	–0.00395912
NaOH (%)	–0.216194508	0.187697723	–0.480910808
Holocellulose (%)	0.077052157	0.040951917	0.327178767
Lignin (%)	0.109422179	0.026174227	0.314914426
Ash (%)	–0.175417187	0.147098099	–0.354676534
Eigenvalue	4.248367093	2.920730104	1.749436627
Proportion of variance (%)	34.57973215	23.77338457	14.23960045
Cumulative variance (%)	34.57973215	58.35311672	72.59271717

RR: Runkel ratio, AR: aspect ratio, FC: flexibility coefficient, RC: rigidity coefficient.