Arundo donax

Arundo donax, Giant Cane, is a tall perennial cane growing in damp soils, either fresh or moderately saline. Other common names include Carrizo, Arundo, Spanish cane, Colorado River Reed, Wild cane, and Giant reed.
Arundo donax is native to eastern and southern Asia, the Mediterranean Basin, and probably also parts of Africa and southern Arabian Peninsula. It has been widely planted and naturalised in the mild temperate, subtropical and tropical regions of both hemispheres (Herrera & Dudley 2003), especially in the Mediterranean, California, the western Pacific and the Caribbean. It forms dense stands on disturbed sites, sand dunes, in wetlands and riparian habitats.

Arundo donax generally grows to 6 metres (20 ft), in ideal conditions it can exceed 10 metres (33 ft), with hollow stems 2 to 3 centimetres (0.79 to 1.18 in) diameter. The leaves are alternate, 30 to 60 centimetres (12 to 24 in) long and 2 to 6 centimetres (0.79 to 2.36 in) wide with a tapered tip, grey-green, and have a hairy tuft at the base. Overall, it resembles an outsize common reed (Phragmites australis) or a bamboo (Subfamily Bambusoideae).

Arundo donax flowers in late summer, bearing upright, feathery plumes 40 to 60 centimetres (16 to 24 in) long, that are usually seedless or with seeds that are rarely fertile. Instead, it mostly reproduces vegetatively, by underground rhizomes. The rhizomes are tough and fibrous and form knotty, spreading mats that penetrate deep into the soil up to 1 metre (3.3 ft) deep (Alden et al., 1998; Mackenzie, 2004). Stem and rhizome pieces less than 5 centimetres (2.0 in) long and containing a single node readily sprouted under a variety of conditions (Boose and Holt, 1999). This vegetative growth appears to be well adapted to floods, which may break up individual A. donax clumps, spreading the pieces, which may sprout and colonise further downstream (Mackenzie 2004).

Arundo donax (L.) is a tall, perennial C3 grass species belongs to the subfamily Arundinoideae of the Poaceae family. The hollow stems, 3 to 5 cm thick, have a cane-like appearance similar to bamboo. Mature stands can reach a height up to 8 m. Stems produced during the first growing season are unbranched and photosynthetic. It is an asexually reproducing species due to seed sterility.

It needs to be established by vegetative propagation, due to a lack of viable seed production. Underground it produces an extensive network of large, but short rhizomes like bulbs, and fibrous tap roots. In the Mediterranean, where a temperate climate is characterized by warm and dry summer and mild winter, giant reed new shoots emerge around March, growing rapidly in June – July and producing stems and leaves. From late July the lower leaves start to dry, depending to seasonal temperature patterns. Crop drying accelerates during autumn when anthesis occurs from the beginning of October to the end of November. In this phonological stage moisture contents fall significantly. In winter-time giant reed stops its growth because of low temperatures and regrowth occurs in the following springtime. In Central Europe giant reed behaves as an annual energy crop for the low soil temperatures and poor freeze tolerance lack of the rhizomes. The base growth temperature reported for giant reed is 7°C, and a maximum cut-off is at 30°C. It has a high photosynthetic capacity, associated with absence of light saturation. Carbon dioxide exchange rates is high compared to other C3 and C4 species. Under natural condition, the maximum CO2 uptake ranged between 19.8 and 36.7 µmol m−2 s−1, depending on irradiance, leaf age, and it is regulated by leaf conductance.