Variation, coordination, and trade-offs between needle structures and photosynthetic-related traits across five Picea species: consequences on plant growth

Table 1 Needle structures for the five studied Picea species

Traits (Unit)	P. glauca	P. mariana	P. likiangensis	P. koraiensis	P. crassifolia	Significance (ANOVA)
NL (mm)	1.10 ± 0.10ab	0.82 ± 0.12c	1.15 ± 0.15a	0.98 ± 0.04b	1.02 ± 0.12b	**
NW (mm)	0.78 ± 0.08b	0.79 ± 0.10b	0.96 ± 0.06a	1.00 ± 0.09a	1.02 ± 0.08a	**
NT (mm)	0.91 ± 0.05c	0.79 ± 0.05d	1.03 ± 0.08ab	1.00 ± 0.02b	1.10 ± 0.07a	**
SD (No./mm²)	60.93 ± 5.67a	51.54 ± 0.63b	49.81 ± 2.48b	41.51 ± 1.95c	32.57 ± 2.32d	**
NSA (mm²)	0.51 ± 0.04c	0.38 ± 0.02d	0.80 ± 0.070a	0.61 ± 0.01b	0.64 ± 0.10b	**
MA (mm²)	0.34 ± 0.02c	0.26 ± 0.02d	0.60 ± 0.05a	0.43 ± 0.01b	0.46 ± 0.06b	**
ETA (mm²)	0.12 ± 0.03a	0.08 ± 0.01b	0.14 ± 0.02a	0.12 ± 0.02a	0.12 ± 0.03a	*
CCA (mm²)	0.040 ± 0.009bc	0.033 ± 0.004c	0.041 ± 0.005bc	0.044 ± 0.002b	0.056 ± 0.007a	**
TMA (mm²)	0.16 ± 0.04a	0.11 ± 0.00b	0.19 ± 0.02a	0.17 ± 0.02a	0.17 ± 0.03a	*
MF (%)	65.89 ± 5.62c	67.75 ± 1.75bc	75.38 ± 2.10a	70.47 ± 2.41bc	71.59 ± 1.12ab	**
ETF (%)	23.97 ± 5.41	20.34 ± 1.62	17.84 ± 1.91	20.27 ± 2.56	17.61 ± 2.02	NS
CCF (%)	7.78 ± 1.20ab	8.73 ± 1.26a	5.18 ± 0.36c	7.22 ± 0.47b	8.74 ± 0.81a	**
TMF (%)	31.75 ± 5.62a	29.06 ± 1.63ab	23.42 ± 1.32c	27.49 ± 2.57bc	26.35 ± 1.24bc	*
LMA (g/m²)	180.34 ± 18.65c	167.93 ± 11.99c	158.10 ± 4.42c	229.67 ± 33.74b	268.50 ± 29.16a	**

NL needle length, NW needle width, NT needle thickness, SD stomatal density, NSA needle section area, ETA and ETF epidermis tissue area and fraction, MA and MF mesophyll area and fraction, CCA and CCF central cylinder area and fraction, TMA and TMF total mechanical tissue area and fraction. Data are mean ± SE. Different letters indicate significant differences among species (P < 0.05). *, statistical significance at P < 0.05; **, statistical significance at P < 0.01

ISSN: 1471-2229