Abstract:

Objective: Phyllostachys violascens 'Prevernalis' is an excellent bamboo species for scattered shoots. Mulching forest ground with organic material promotes early emergence of bamboo shoots and significantly improves economic benefits. Mulching will cause drastic changes to the underground growing conditions for the rhizome system of P. violascens 'Prevernalis' forests. Exploring the changes of sheath leaf traits, and taste quality of bamboo shoots under mulching and the relationship between the changes is of great significance to reveal the basis of formation of the taste quality of bamboo shoots. Method: Taking mulched bamboo shoots and natural bamboo shoots of P. violascens 'Prevernalis' with similar management level as the study subject, sheath leaf traits and taste quality of bamboo shoots were determined and analyzed. Result: 1) Compared with the natural shoots of P. violascens 'Prevernalis', the sheath leaves thickness, moisture content, aspect ratio and aspect ratio plasticity index, carotenoid and anthocyanin contents of the mulched bamboo shoots significantly increased by 317.65%, 29.82%, 22.90%, 26.32%, 567.59% and 193.93%, respectively, while the plasticity indices of single leaf dry weight, moisture content, length, area, and circumference and chlorophyll(a, b, a+b) contents of sheath leaves significantly decreased by 69.44%, 68.18%, 17.65%, 21.13%, 20.83%, 94.92%, 76.15% and 92.76%, respectively, indicating that the mulching does not have a significant effect on the morphology of sheath leaves, but it is important for the morphological plasticity index and pigment content influences. 2) Compared with the natural shoots, the soluble sugar content, sugar to acid ratio, and content and proportion of sweet amino acids of mulched shoots significantly increased by 43.68%, 89.55%, 128.57% and 125%, respectively, while the contents of total acid, oxalic acid, cellulose, bitter amino acids, and aromatic amino acids, and content and proportion of delicious amino acids opposite, indicating that mulching could significantly reduce the bitterness and roughness of bamboo shoots, while significantly improve the sweetness of bamboo shoots. 3) Redundancy analysis showed that chlorophyll(a, b, a+b) of the sheath leaves had significant negative effects on the taste quality of bamboo shoots, while the thickness of sheath leaves, aspect ratio, moisture content, carotenoids and anthocyanins had significant positive effects. Conclusion: P. violascens 'Prevernalis' shoots can cope with the obvious changes of temperature, humidity and light under mulching conditions through the adaptive changes of morphological plasticity index and pigment content of sheath leaves, and the taste quality of bamboo shoots under mulching is significantly improved. The pigment content of the sheath leaves is closely related to the taste quality of bamboo shoots, which may be an important organ that affects the taste quality of bamboo shoots through light signal transduction.

Key words: Phyllostachys violascens 'Prevernalis', bamboo shoot, sheath leaf, form, pigment, taste quality, mulching cultivation