荔枝空中压条苗根系生长动态及与地上部生长的相互关系

Root Growth Pattern of Litchi Air Layering Plants and Its Relation to Shoot Growth

以‘糯米糍’荔枝Litchi chinensis Sonn．空中压条苗为试材，利用根箱栽培研究了周年内3株荔枝幼树根系形态、动态生长以及与地上部枝梢生长间的相互关系．结果表明：荔枝不同类型的根在形态上差异较大，侧根粗壮发达，生长周期长，可持续生长8～10周；须根纤细茂密，寿命只有2～3周．2株苗的根系周年内有2次大的生长峰和2次小的生长峰，根梢生长表现为交替生长．1株苗在周年内只有1次大的生长峰和4次小的生长峰，根梢生长表现为同步生长．3株幼树根梢比值均在1．0左右，表明地上和地下部等量生长．根系生长峰的出现主要表现为新根数量的增加而非原有根系的延长生长．

Three ‘Nuomici＇ litchi （Litchi chinemis Sonn. ） air layering plants were cultivated in root observation chambers to investigate the root morphology and growth pattern, stem extension growth, and relationships between root and stem growth during 12 months. The results showed that different root types varied greatly in morphology, lateral root system was coarse and vigorous with long life span of 8-10 weeks,dense fine roots could only survive for 2-3 weeks ;Two air layering plants had 2 higher root growth peaks and 4 lower peaks,while root and stem growth had an alternate growth pattern during one-year period ; One air layering plant had one higher root growth peak and 4 lower peaks, while root and stem growth had a synchronous extension pattern ; The ratio of root to shoot of 3 plants ranged about 1.0 that indicated root and aerial part grew at equal mass amount. The increase of new root number rather than continuous extension of old root contributed to the occurrence of growth peak.