Comparing Morphological Traits and Chlorophyll Fluorescence in Sun and Shade Leaves of Eucalyptus hybrid in an Ex-Tin Mine

Abstract

Selecting suitable tree species is one of the most important factors determining the success of rehabilitation
initiatives or projects in degraded areas such as ex-mining sites. The ability of selected trees to survive and
establish in these areas can be explained physiologically through examination of their leaves. Among four
species planted in May 2022 in an ex-tin mining area in Malim Nawar, Perak, this study has chosen to focus
on the Eucalyptus hybrid due to its superior survival and growth. A total of four E. hybrid trees were
selected with an average height of 2.71 ± 0.65 m and collar diameter of 36.23 ± 8.75 mm. Five sun leaves
and another five shade leaves were sampled from each tree for measurements of leaf area, moisture content,
chlorophyll and plant efficiency. Sun leaf was found to have significantly higher (p < 0.01) length and width
compared to shade leaf which contributed to a larger area for the sun leaf (28.40 ± 3.98 cm2) than that of
the shade leaf (22.88 ± 5.16 cm2). Sun leaf also had higher chlorophyll content compared to shade leaf (p
< 0.05). The Chl-a fluorescence analysis results indicated better photosynthetic performance in sun leaves
with higher PIABS and PItotal than shade leaves. Our findings thus showed the morphological adaptation as
well as physiological responses of sun and shade leaves of Eucalyptus hybrid when planted in an open
degraded area.