AvsCa <- read.csv("AvsCa.csv")
ggplot(data = AvsCa, aes(x = Ca, y = A, group = Light_Level, color = Light_Level))+
geom_point()+
geom_line()+
labs(y=expression("CO"["2"]*~"Assimilation Rate"~italic(A)~"(µmol"~~m^-2*s^-1*")"), x=expression("Ambient CO"["2"]*~"Concentration, C"["a"]*~"(µmol mol"^-1*")"))+
scale_y_continuous(sec.axis=dup_axis())+
theme_set(theme_bw())+
theme(axis.ticks.length=unit(-0.1, "cm"), axis.text.x.top=element_blank(), axis.text.y.right=element_blank(), axis.title.x.top=element_blank(), axis.title.y.right=element_blank(), panel.grid.major = element_blank(), panel.grid.minor = element_blank(), legend.position = c(.2,.8))+
scale_color_discrete(name="Qin (Light Intensity)", labels=c(expression("1000 µmol m"^-2*s^-1),expression("1500 µmol m"^-2*s^-1)))
I tried adding theme(axis.title.y = element_text(margin = margin(t = 0, r = 20, b = 0, l = 0)))
but it did not work