Characteristics of “Number of Veins” to Estimate Leaf Maturity in Pteris mutilata (Pteridaceae)

Abstract

In this report, the author suggests that the number of veins (NV) is useful to estimate leaf maturation for a tropical fern Pteris mutilafa, as has been established in ferns of cool temperate regions. NV expressed developmental stages better than any other leaf size parameters, such as blade length, blade width, stipe length, and total length (blade+ stipe length). The leaf shape became more oblong and/or slender after the plant matured, which could be measured by two shape parameters, (blade width)/(total length) and (blade width)/(blade length). Principal component analysis using all the morphological parameters showed that NV is categorized into size parameters, although NV has been considered to differ somehow from the other size parameters. Thus NV represents one of the size parameters that is the most appropriate to estimate leaf maturation.

Frond size, shape and fertility of Thelypteris confluens (Thunb.) C. V. Morton in wetlands disturbed by human activities in Hokkaido, northern Japan

“…In models with single measurement variables, NV was the most powerful variable for detecting the frond fertility of ferns, such as five Polystichum ferns (Sato, 1985b) and three Dryopteris ferns (Sato and Tsuyuzaki, 1988). NV predicts the frond fertility of Pteris mutilata Burn., which develops dimorphic fronds depending on fertility, better than the other size and shape parameters, i.e., FL, BL and aspect ratios (Tsuyuzaki, 2000). NV is tightly related to the frond maturation of ferns, including Thelypteris confluens, as previously described.…”

“…The allometric relationship between the measured variables was selectively assessed by using standardized major axis tests (SMA) to observe the site-based differences in the allocation of the human disturbance rank scores (Warton et al, 2006). Since frond characteristics are related to BL in most examined ferns (Sato et al 1989, Tsuyuzaki 2000, allometry was obtained between the BL and the other variables for fertile and sterile fronds. All the statistical analyses were performed by R software (version 3.6.2) (R Core Team, 2019) with the libraries MASS (Venables and Ripley, 2002) and smatr (Warton et al, 2012).…”

“…Thelypteris confluens forms dimorphic fronds: the fertile fronds have thin and curling pinnae whereas the sterile fronds have flattened pinnae (Kavak, 2014) when they produce sori between late summer and early autumn in Hokkaido, Japan (Takita, 2001). Because frond fertility is a key to anticipating the population dynamics of ferns, a suitable predictor of frond fertility is required (Tsuyuzaki, 2000). Furthermore, nondestructive methods for monitoring population dynamics are preferable (Hoyo and Tsuyuzaki, 2013).…”