Chlorophyll presents higher absorption values in the visible spect, specially in the blue and red bands. The celular structure of the leaves presents higher reflectance values in the near infrarred (NIR). Chloroplasts present higher absorption values in the green band. Reflectances values in the NIR are not affected by chloroplasts, but it is highly reflectance by spongy mesophiles ( Murillo, P.J., Carbonell, J.A. 2012. Principios y aplicaciones de la percepción remota en el cultivo de la caña de azúcar en Colombia. Cali: Centro de Investigación de la Caña de Azúcar de Colombia.).

Please have a look at the links about spectral properties of leaves & plants:

http://cstars.metro.ucdavis.edu/files/3613/4419/0702/Lecture_3-Leaves__Plants.pdf

http://www.forestwatch.sr.unh.edu/pdfs/Gatesetal_1965.pdf

http://www.seos-project.eu/modules/remotesensing/remotesensing-c01-p05.html

According to the fig. in the last link the vegetation has maximum reflectance around 0,75µm to ~1,4µm.

Please have a look also at:

http://www.seos-project.eu/modules/agriculture/agriculture-c01-s01.html

It depends on your application and what is your final goal, you may consider the terahertz region as well

Green leaves reflect green and yellow light as well as infra-red :)

Chlorophyll presents higher absorption values in the visible spect, specially in the blue and red bands. The celular structure of the leaves presents higher reflectance values in the near infrarred (NIR). Chloroplasts present higher absorption values in the green band. Reflectances values in the NIR are not affected by chloroplasts, but it is highly reflectance by spongy mesophiles ( Murillo, P.J., Carbonell, J.A. 2012. Principios y aplicaciones de la percepción remota en el cultivo de la caña de azúcar en Colombia. Cali: Centro de Investigación de la Caña de Azúcar de Colombia.).

That's the theory concisely and well explained, Judit

For a range of empirical findings from the outdoors you may consult Esselink & Gils 1985 (grassland; customized ground spectrometer) and Fauzi et al. 2013 (mangrove; airborne spectrometer).

Visible region (Greenlight = (500 to 600 nanometers) and Near infra-Red region of the spectrum are mostly reflected by green vegetation since we can’t see NIR so we only see the green color of vegetation