Evolutionary correlation of water-related traits between different structures of Dendrobium plants

Botanical Studies

Table 1 Correlation coefficients (r) of the first two axes of PCA and phylogenetic signals (K) for the functional traits of Dendrobium species in this study

Functional traits	Codes	Units	Species mean value PCA		Phylogenetic signals
Functional traits	Codes	Units	First major axis r	Second major axis r	K	P
Leaf dry mass	LDM	mg	0.904^**	0.085	1.163	0.044
Leaf water content	LWC	%	− 0.857^**	0.144	1.531	0.007
Leaf dry matter content	LDMC	%	0.863^**	− 0.209	1.720	0.009
Specific leaf area	SLA	cm²/g	− 0.714^*	0.640	1.415	0.019
Mesophyll thickness	MT	μm	− 0.341	− 0.747^*	0.931	0.138
Upper epidermal cell size	UECS	μm²	− 0.415	0.488	0.941	0.363
Stomatal density	SD	no./mm²	0.735^*	− 0.535	1.537	0.005
Stomatal volume	SV	μm³	0.204	0.895^**	0.984	0.096
Stomatal area index	SAI	10⁻² no.	0.689	− 0.155	1.108	0.046
Vein density	VD	mm/mm²	0.301	0.071	0.862	0.366
Pseudobulb length	PL	cm	− 0.032	0.967^***	1.022	0.041
Pseudobulb width	PW	mm	0.878^**	− 0.211	1.026	0.042
Pseudobulb internode length	PIL	10⁻¹ mm	0.513	0.789^*	0.904	0.241
Flower dry mass	FDM	mg	0.474	0.767^*	1.143	0.025
Flower water content	FWC	%	− 0.748^*	− 0.457	0.888	0.204
Flower petal vein number	FPVN	no.	0.903^**	0.037	0.921	0.393
Flower number	FN	no.	0.477	0.033	0.906	0.607