We investigated the influence of season on the rooting be- haviour of eight important bamboo species viz., Bambusa balcooa, B. bambos, B. nutans, B. tuMa, B. vulgaris, Dendrocalamus giganteus, D. hamiltonii and D. str...We investigated the influence of season on the rooting be- haviour of eight important bamboo species viz., Bambusa balcooa, B. bambos, B. nutans, B. tuMa, B. vulgaris, Dendrocalamus giganteus, D. hamiltonii and D. strictus. We collected 2-3 node culm cuttings in three growing seasons viz. spring （March）, summer （June） and rainy （August） from superior candidate plus clumps （CPCs） centralized in the germplasm garden. Cuttings were placed horizontally in sand and were provided with intermittent misting at regular intervals. Bamboo species exhibited differential rhizogenesis behavior in different seasons. The study reveals significant variation in sprouting and rooting behaviour in different bamboo species. B. bambos had maximum rooting （78.89%）, followed by B. vulgaris （74.44%）. In general, the potential of different bamboo species for rooting was found to be in the order： B. bambos 〉 B. vulgaris 〉 B. balcooa 〉 D. hamiltonii 〉 B. tulda 〉 D. strictus 〉 D. giganteus 〉B. nutans. The maximum rooting was recorded in spring （56.67%）, which was closely followed by summer （54.58%）. In winter season, minimum rooting （36.67%） was observed. The interaction effect of species x season was also significant on sprouting and rooting pa- rameters. In B. balcooa, B. nutans, B. vulgaris, D. hamiltonii and D. strictus, cuttings collected in summer season showed maximum sprouting and rooting, whereas, B. bambos, B. tulda and D. giganteus had maximum rooting in spring. The maximum number of roots developed per cutting was observed in B. tulda （43.8） during spring season.展开更多
为揭示毛竹林在低磷胁迫下维持高生产力的根系磷获取策略,本研究通过原位磷添加试验(对照0 kg P·hm^(-2)·a^(-1)、低磷50 kg P·hm^(-2)·a^(-1)和高磷100 kg P·hm^(-2)·a^(-1)),分析磷添加对毛竹鞭根形态...为揭示毛竹林在低磷胁迫下维持高生产力的根系磷获取策略,本研究通过原位磷添加试验(对照0 kg P·hm^(-2)·a^(-1)、低磷50 kg P·hm^(-2)·a^(-1)和高磷100 kg P·hm^(-2)·a^(-1)),分析磷添加对毛竹鞭根形态和生理特征、根系分泌物和菌根性状的调控机制。结果表明:与对照相比,磷添加显著增加了比表面积(低磷:19.1%;高磷:23.4%)、根系氮(低磷:42.6%;高磷:37.7%)和磷含量(低磷:83.8%;高磷:115.3%),但显著抑制了磷酸酶活性(低磷:22.2%;高磷:30.4%)和丛枝菌根真菌(AMF)侵染率(低磷:24.1%;高磷:25.3%);低磷与高磷处理间无显著差异。磷添加处理显著提升根际土壤pH值、柠檬酸磷、酶解磷、盐酸磷及微生物生物量碳、氮、磷。其中,高磷处理柠檬酸磷、酶解磷和盐酸磷含量显著高于低磷处理。根际土壤磷组分与根系比表面积、磷酸酶活性及AMF侵染率呈显著相关,表明根际土壤磷组分是驱动鞭根磷获取途径转变的重要因子。磷添加处理下毛竹鞭根由“分泌物-菌根共生”资源保守型途径向“高表面积”的资源获取型途径转变。展开更多
The humid agroclimatic conditions of Kerala,India permit the cultivation of an array of bamboo species of which Dendrocalamus strictus Roxb.(Nees.) is an important one on account of its high growth rate and multiple u...The humid agroclimatic conditions of Kerala,India permit the cultivation of an array of bamboo species of which Dendrocalamus strictus Roxb.(Nees.) is an important one on account of its high growth rate and multiple uses. Stand density, a potential tool in controlling the productivity of woody ecosystems, its effect on growth and root distribution patterns may provide a better understanding of productivity optimization especially when bamboo-based intercropping options are considered.Growth attributes of 7-year-old bamboo(D. strictus) stands managed at variable spacing(4×4 m, 6×6 m, 8×8 m,10×10 m, 12×12 m) were studied. Functional root activity among bamboo clumps were also studied using a radio tracer soil injection method in which the radio isotopeP was applied to soil at varying depths and lateral distances from the clump. Results indicate that spacing exerts a profound influence on growth of bamboo. Widely spaced bamboo exhibited higher clump diameters and crown widths while clump heights were better under closer spacing. Clump height was 30% lower and DBH 52%higher at the widest spacing(12×12 m) compared to the closest spacing(4×4 m). With increasing soil depth and lateral distance, root activity decreased significantly. Root activity near the clump base was highest(809 counts per minute, cpm; 50 cm depth and 50 cm lateral distance) at 4×4 m. Tracer study further showed wider distribution of root activity with increase in clump spacing. It may be concluded that the intensive foraging zone of bamboo is within a 50-cm radius around the clump irrespective of spacing. N, P and K content in the upper 20 cm was 2197,21, and 203 kg/ha respectively for the closely spaced bamboo(4×4 m) which were significantly higher than corresponding nutrient content at wider spacings. About 50% of N, P and K were present within the 0–20 cm soil layer, which decreased drastically beyond the 20 cm depth.The results suggest that stand management practices through planting density regulation can modify the resource acquisition patterns of D. strictus which in turn can change growth and productivity considerably. Such information on root activities, spatial and temporal strategies of resource sharing will be helpful in deciding the effective nutrition zone for D. strictus. Further, the study throws light on the spatial distribution of non-competitive zones for productivity optimization yields, especially when intercropping practices are considered.展开更多
基金supported by National Mission on Bamboo Applications (NMBA),Department of Science & Technology,New Delhi, India
文摘We investigated the influence of season on the rooting be- haviour of eight important bamboo species viz., Bambusa balcooa, B. bambos, B. nutans, B. tuMa, B. vulgaris, Dendrocalamus giganteus, D. hamiltonii and D. strictus. We collected 2-3 node culm cuttings in three growing seasons viz. spring （March）, summer （June） and rainy （August） from superior candidate plus clumps （CPCs） centralized in the germplasm garden. Cuttings were placed horizontally in sand and were provided with intermittent misting at regular intervals. Bamboo species exhibited differential rhizogenesis behavior in different seasons. The study reveals significant variation in sprouting and rooting behaviour in different bamboo species. B. bambos had maximum rooting （78.89%）, followed by B. vulgaris （74.44%）. In general, the potential of different bamboo species for rooting was found to be in the order： B. bambos 〉 B. vulgaris 〉 B. balcooa 〉 D. hamiltonii 〉 B. tulda 〉 D. strictus 〉 D. giganteus 〉B. nutans. The maximum rooting was recorded in spring （56.67%）, which was closely followed by summer （54.58%）. In winter season, minimum rooting （36.67%） was observed. The interaction effect of species x season was also significant on sprouting and rooting pa- rameters. In B. balcooa, B. nutans, B. vulgaris, D. hamiltonii and D. strictus, cuttings collected in summer season showed maximum sprouting and rooting, whereas, B. bambos, B. tulda and D. giganteus had maximum rooting in spring. The maximum number of roots developed per cutting was observed in B. tulda （43.8） during spring season.
文摘为揭示毛竹林在低磷胁迫下维持高生产力的根系磷获取策略,本研究通过原位磷添加试验(对照0 kg P·hm^(-2)·a^(-1)、低磷50 kg P·hm^(-2)·a^(-1)和高磷100 kg P·hm^(-2)·a^(-1)),分析磷添加对毛竹鞭根形态和生理特征、根系分泌物和菌根性状的调控机制。结果表明:与对照相比,磷添加显著增加了比表面积(低磷:19.1%;高磷:23.4%)、根系氮(低磷:42.6%;高磷:37.7%)和磷含量(低磷:83.8%;高磷:115.3%),但显著抑制了磷酸酶活性(低磷:22.2%;高磷:30.4%)和丛枝菌根真菌(AMF)侵染率(低磷:24.1%;高磷:25.3%);低磷与高磷处理间无显著差异。磷添加处理显著提升根际土壤pH值、柠檬酸磷、酶解磷、盐酸磷及微生物生物量碳、氮、磷。其中,高磷处理柠檬酸磷、酶解磷和盐酸磷含量显著高于低磷处理。根际土壤磷组分与根系比表面积、磷酸酶活性及AMF侵染率呈显著相关,表明根际土壤磷组分是驱动鞭根磷获取途径转变的重要因子。磷添加处理下毛竹鞭根由“分泌物-菌根共生”资源保守型途径向“高表面积”的资源获取型途径转变。
基金financially supported by the Kerala Agricultural University
文摘The humid agroclimatic conditions of Kerala,India permit the cultivation of an array of bamboo species of which Dendrocalamus strictus Roxb.(Nees.) is an important one on account of its high growth rate and multiple uses. Stand density, a potential tool in controlling the productivity of woody ecosystems, its effect on growth and root distribution patterns may provide a better understanding of productivity optimization especially when bamboo-based intercropping options are considered.Growth attributes of 7-year-old bamboo(D. strictus) stands managed at variable spacing(4×4 m, 6×6 m, 8×8 m,10×10 m, 12×12 m) were studied. Functional root activity among bamboo clumps were also studied using a radio tracer soil injection method in which the radio isotopeP was applied to soil at varying depths and lateral distances from the clump. Results indicate that spacing exerts a profound influence on growth of bamboo. Widely spaced bamboo exhibited higher clump diameters and crown widths while clump heights were better under closer spacing. Clump height was 30% lower and DBH 52%higher at the widest spacing(12×12 m) compared to the closest spacing(4×4 m). With increasing soil depth and lateral distance, root activity decreased significantly. Root activity near the clump base was highest(809 counts per minute, cpm; 50 cm depth and 50 cm lateral distance) at 4×4 m. Tracer study further showed wider distribution of root activity with increase in clump spacing. It may be concluded that the intensive foraging zone of bamboo is within a 50-cm radius around the clump irrespective of spacing. N, P and K content in the upper 20 cm was 2197,21, and 203 kg/ha respectively for the closely spaced bamboo(4×4 m) which were significantly higher than corresponding nutrient content at wider spacings. About 50% of N, P and K were present within the 0–20 cm soil layer, which decreased drastically beyond the 20 cm depth.The results suggest that stand management practices through planting density regulation can modify the resource acquisition patterns of D. strictus which in turn can change growth and productivity considerably. Such information on root activities, spatial and temporal strategies of resource sharing will be helpful in deciding the effective nutrition zone for D. strictus. Further, the study throws light on the spatial distribution of non-competitive zones for productivity optimization yields, especially when intercropping practices are considered.
