Observations of Malosma laurina seedlings in Sycamore Canyon, Malibu, CA, exhibit abnormally small and wrinkled leaves. We propose that the prolonged drought in California’s Santa Monica Mountains has lead to physical malformations indicative of water strain in the leaves of M. laurina plants. In this experiment, we tested water relations of six M. laurina plants found on Pepperdine University’s Malibu campus showing similar leaf patterns to those found in Sycamore Canyon. Six M. laurina plants devoid of the abnormal leaf growth patterns functioned as our control group. Stomatal conductance, water potential, and leaf mass to area data was gathered using LI-1600 Steady State Porometer, Scholander-Hammel Pressure Chamber, LI-3100 Area Meter, and enclosed scale measurements. ANOVA and Student’s t-Test reports indicate a significant difference in total stomatal conductance between control and test plants, (93% confidence level). Our tests furthermore indicate a statistical difference in total stomatal conductance between abnormal leaves compared to relatively normal leaves on the same branch of experimental plants, (P = 0.014). Water potential in wrinkled leaves is more negative than mature leaves closer to the apical meristem of the same branch, (P = 0.02). Leaf mass to area ratios show no statistical differences but reflect normal thickness trends. Evidence supports our conclusion that prolonged drought has caused abnormal leaf growth in M. laurina plants within the Santa Monica Mountains.
Bae, Grace S. M.; Foster, Majie C.; Stein, MaryElizabeth S.; and Taylor, Mariah K., "Morphological Changes in Malosma laurina Due to Prolonged Drought in the Santa Monica Mountains" (2015). Pepperdine University, Featured Research. Paper 202.