| Physiological integration is one of the most important characteristics of clonal plants and directly affected the survival, growth, reproduction, expansion and resource utilization of clonal plant. Clonal plants redistribute water resources obtained through physiological integration to help vulnerable plaques ramets overcome environmental stress, so as to improve the fitness of the whole system. Bamboo is an important part of forest resources in China, but also an important class of clonal plants. In the context of global climate changing, explore the physiological integration especially water physiological integration condition, strength and influence factors of bamboo plant has an important ecological significance. To explore the characteristics of water physiological integration of Indocalamus decorus clonal system in heterogeneous water conditions, the study with connected Indocalamus decorus clonal ramets under different water potential, ramets ratio, length of spacer and matrix nitrogen nutrition were conducted and t the antioxidant enzyme, content of osmotic regulation substance, reactive oxygen species, MDA, photosynthetic pigment and relative electric conductivity were determined were determined. Main results as follows:1) Effect analysis of water physiological integration occurrence condition of Indocalamus decorus based on antioxidant system. Setting three water potential gradients of soil matrix (90%-60%、60%-30%、90%-30%) and three matrix relative water content (90%±5% High water potential、60%±5% Intermediate water potential and 30%±5% Low water potential) with connected Indocalamus decorus clonal ramets to explore the occurrence condition of water water physiological integration. The results showed that activity of CAT and SOD, soluble protein content of low water potential ramets increased while POD activity and MDA content decreased with the increasing of water potential difference between Indocalamus decorus ramets, high water potential ramets had opposite regulation. Antioxidant physiological indicators of intermediate water potential ramets had no significant differences during all the treatment time. The study indicated that water physiological integration existed in Indocalamus decorus clonal system under heterogeneous water environment. Ramets needed to guaranteed its own water demand in first. Intense water transfer from high water potential ramets to low water potential ramets would be taken place when the water condition superfluous and deficit were existed between ramets. The water potential difference of ramets is bigger, the intensity of physiological integration is stronger. Clonal ramets had "selfish" and "altruistic" behavior on water physiological integration.2) Effects of ramet ratio on water physiological integration in Indocalamus decorus— activity of antioxidant system and photosynthetic pigment content.Setting two matrix relative water content(90%±5% High water potential and 30%±5% Low water potential) and five ramet ratio (1:3,1:2,1:1,2:1,3:1)with connected Indocalamus decorus clonal ramets to explore the ramet ratio effect of water physiological integration. The results showed that water physiological integration existed in Indocalamus. decorus clonal system under heterogeneous water environment, water transfer from high water potential ramets to low water potential ramets. With the increase of ramet ratio, integration intensity enhanced, the benefit of receptor ramet and consumption of donor ramet increased. With the increasing of treatment time, water integration intensity between connected clonal ramets increased in early time but weakened in later, reflecting that the consumption-benefit effect of donor ramets and receptor ramets in time series is changing, the consumption-benefit effect is more obvious in early stage of the treatment. The results indicated that environment water gradient in clonal system which is a potential source sink relationship, the direction and intensity of physiological integration was determined by the relationship of water supply and demand between the internal clonal system. The research provided a theoretical basis for artificial water supply of commercial bamboo forests.3) Effects of spacer length on water physiological integration of bamboo-based on activity of antioxidant system and photosynthetic pigment content in Indocalamus decorus.Setting two water potential gradients of soil matrix (90%-30%、60%-30%) and three matrix relative water content(90%±5%(High water potential)、60%±5%(Intermediate water potential) and 30%±5%(Low water potential) with connected Indocalamus decorus clonal ramets to explore the spacer length effect of water physiological integration. The results showed that water potential gradients and spacer length affected the water physiological integration of Indocalamus decorus clonal ramets. Antioxidant enzymes activity, soluble protein and photosynthetic pigment content of low water potential receptor ramets decreased, while leaf relative electric conductivity and MDA content increased significantly with the water potential difference increasing and spacer distance shortening between Ⅰ. decorus ramets. The water potential is higher and the spacer is longer, the antioxidant enzymes activity, soluble protein and photosynthetic pigment content of donor ramets is higher and the leaf relative electric conductivity and MDA content is lower. All results indicated that water transfer from high water potential ramets to low water potential ramets would be taken place in Ⅰ. decorus clonal system under heterogeneous water environment. The water potential difference between ramets is bigger, and the length of spacer is shorter, the intensity of physiological integration is stronger, the benefit of receptor ramets is more obvious.4) Effects of nitrogen nutrition on water physiological integration of bamboo-based on activity of antioxidant system and photosynthetic pigment content in Indocalamus decorus.Setting two matrix relative water content(90%±5% High water potential and 30%±5% Low water potential) and six matrix nitrogen nutrition ratio (ON:1N、ON:2N、1N:2N、1N:ON、 2N:0N、2N:1N) with connected Indocalamus decorus clonal ramets to explore the matrix nitrogen nutrition effect of water physiological integration. The results showed that the matrix nitrogen nutrition content of high water potential ramets is higher, the antioxidant enzyme activities and osmotic regulation substance, photosynthetic pigment content of donor ramets leaves is lower, relative conductivity and MDA content of donor ramets is higher, antioxidant activity and osmotic regulation substance, photosynthetic pigment content of connected receptors ramets is higher, relative conductivity and MDA content of connected receptors ramets is lower. Antioxidant enzyme activity, osmotic adjustment, photosynthetic pigment content of both donor and receptors ramets significantly decreased and relative conductivity and MDA content significantly increased with the increasing of Low water potential ramets matrix nitrogen nutrition. All results indicated that increase matrix nitrogen nutrition content of either high water potential ramets or low water potential ramets can improve the water physiological integration strength in Indocalamus decorus clonal system, but low water potentials ramets applied nitrogen nutrition make receptor ramets water environment more worse and increased water stress injuries of receptor ramets. |
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