Subjects: Biology >> Botany >> Applied botany submitted time 2024-03-26 Cooperative journals: 《广西植物》
Abstract： Phosphorus (P) is one of the essential elements for plant growth and is a key factor in maintaining the productivity of subtropical forest ecosystems. Chinese fir (Cunninghamia lanceolata) is mainly distributed in subtropical areas of China, and its soil acidification and phosphorus utilization efficiency are low. It is of great significance to study the effect of Chinese fir plantation transformation on soil P for the stability of ecosystem and sustainable forest management. In this study, the rhizosphere soil and non-rhizosphere soil were collected from the replanted Chinese fir plantation, Castanopsis hystrix plantation, Mytilaria laosensis plantation and the mixed plantation of Castanopsis hystrix and Mytilaria laosensis on the cutting-blank of Chinese fir plantation in South Asia, and the effects of soil P component and transformation on the transformation of Chinese fir plantation into broadleaved forest were studied. The results showed that: (1) The content of microbial biomass phosphorus and the activity of acid phosphatase in rhizosphere and non-rhizosphere soil of the modified Castanopsis hystrix plantation, Mytilaria laosensis plantation and the mixed plantation of Castanopsis hystrix and Mytilaria laosensis were significantly higher than those of Chinese fir plantation. Soil total phosphorus of Castanopsis hystrix plantation and the mixed plantation of C. hystrix and Mytilaria laosensis was more easily converted to quick available phosphorus than those of Chinese fir plantation and Mytilaria laosensis plantation. (2) The contents of calcium chloride extraction phosphorus in rhizosphere and non-rhizosphere soil of Castanopsis hystrix plantation and the mixed plantation of Castanopsis hystrix and Mytilaria laosensis were significantly higher than those of Chinese fir plantation and M. laosensis plantation, and the contents of enzyme extraction phosphorus, hydrochloric acid extraction phosphorus and citric acid extraction phosphorus in rhizosphere and non-rhizosphere soil of Mytilaria laosensis plantation and Castanopsis hystrix/Mytilaria laosensis mixed plantation were significantly higher than those of Chinese fir plantation and Castanopsis hystrix plantation. (3) RDA results showed that soil water content and microbial biomass carbon were the key factors regulating P components in rhizosphere and non-rhizosphere soils, respectively. In summary, the transformation of Chinese fir plantation into broadleaved forest is conducive to the storage and supply of forest soil P, and this study provides an important scientific basis for tree species selection and management strategies to improve soil P availability in south subtropical plantations.
Subjects: Biology >> Botany >> Applied botany submitted time 2024-02-07 Cooperative journals: 《广西植物》
Abstract： In order to understand the adaptation ability of Syzygium hancei seedlings to environmental factors in three different habitats under natural regeneration conditions. The present study collected the current year’s S. hancei seedlings as experimental materials that regenerated in naturally coastal environments of Guangxi, and then antioxidant enzyme activities, soluble sugar content, malondialdehyde content and photosynthetic pigments in leaves and roots were analysed. The results were as follows: (1) Variance analysis (ANOVA) was conducted on multiple environmental factors, which indicated light intensity was highly significant differences, soil surface temperature and water content were not significant differences between the three sample plots. (2) Various light density resulted in the changes of leaves and roots physiological characteristics of seedlings in different habitats. With the light density increasing, leaves’ superoxide dismutase (SOD) activity, soluble sugar (SS), malondialdehyde (MDA), and chlorophyll a/b contents, and roots’ peroxidase (POD) activity of seedlings were significantly higher in habitat B than in habitat A; while leaves’ POD activity, chlorophyll a , chlorophyll b and total chlorophyll contents, and roots’ SOD activity, SS and MDA contents were higher in habitat A than in habitat B. (3) With light intensity decreasing, seedlings that regenerated in habitat B represented significantly higher SOD activity and MDA content in leaves, and POD activity in roots than regenerated in habitat A; however, these seedlings that regenerated in habitat A represented significantly higher POD activity and SS content in leaves compare with regenerated in Habitat B; chlorophyll a , chlorophyll b, total chlorophyll,and SS contents, and roots’ MDA content were significantly higher in habitat A than in habitat B firstly, and then changed to Habitat B being significantly higher than Habitat A; chlorophyll a/b content and roots’ SOD activity were significantly higher in Habitat A firstly and then changed to Habitat A being significantly higher than Habitat B. (4) Comprehensive analyses show that the physiological and biochemical characteristics of all three habitats show different adaptation abilities, in the meanwhile, photoinhibition occurrs in habitat B that is with the lowest canopy density, hence, some manual adjusting practices are need to create a moderate light environment, and provide a suitable condition for promoting the natural regeneration of seedlings.
Subjects: Biology >> Botany >> Applied botany submitted time 2024-01-03 Cooperative journals: 《广西植物》
QIN Huiting
YAN Jinliu
HUANG Haimei
LI Jiajun
XIANG Mingzhu
LI Changhang
HUANG Xueman
ZHAO Lijun
YOU Yeming
Abstract： Organic phosphorus (Po) is an important part of soil phosphorus reservoir. In order to investigate the effects of the soil Po fraction distribution properties in Pinus massoniana plantations after close to nature silviculture, we investigated the pure P. massoniana plantations (PP) and P. massoniana broad leaved mixed plantations (CP) after close to nature silviculture in southern subtropical China. After collecting 0~10 cm soil sample, it was screened into >2 mm, 0.25~2 mm and <0.25 mm particle size fractions using the dry sieving method. We measured the Po fraction, microbial biomass phosphorus (MBP) and acid phosphatase (ACP) activity in the bulk soil and aggregates to understand the distribution of the Po fraction and its drivers. The results were as follows: (1) Soil Po fractions changed in CP compared to PP, with highly recalcitrant organophosphorus (HRO P) and moderately labile organophosphorus (MLO P) markedly greater in the bulk soil and soil aggregates than in PP (P 0.05), while labile organophosphorus (LO P) and moderately recalcitrant organophosphorus (MRO P) were not significantly different in CP and PP. In addition, there was no consistent pattern of change in the Po fractions in the bulk soil and soil aggregates between PP and CP. (2) The size of the proportion of each form of Po in PP was HRO P>MRO P>MLO P>LO P, while CP was HRO P>MLO P>MRO P>LO P. (3) The MBP and ACP activity in CP was markedly greater than that of PP in the bulk soil and the soil aggregates, and there was a tendency for the ACP activity to increase with the decrease in the size of the aggregates. (4) Redundancy analysis revealed that soil available phosphorus (AP), mean weight diameter (MWD), MBP and total nitrogen (TN) were the main drivers of the soil Po fraction. In conclusion, the close to natural forest management model is beneficial to the accumulation and transformation of soil phosphorus in P. massoniana plantation. This study provides a theoretical basis for the improvement of soil quality and productivity in P. massoniana plantations.
Subjects: Biology >> Botany >> Applied botany submitted time 2023-12-26 Cooperative journals: 《广西植物》
Abstract： The purpose of the study was to characterize the changes in soil microbial abundance and diversity and carbon utilization of Podocarpus macrophyllus by adding different levels of nitrogen (N), phosphorus (P) and potassium (K), to reveal the response of P. macrophyllus soil microorganisms to different nutrient levels of N, P and K and to provide a theoretical basis for fertilization and management of P. macrophyllus from the perspective of microorganisms. Using two-year old P. macrophyllus seedlings as the test species, the researchers controlled the gradient of N, P and K nutrient levels using the L9 orthogonal test in the potted soil. The dilution plate coating method and Biolog-ECO microplate method were used to explore the effects of different soil nutrient levels on the amount and community diversity of P. macrophyllus soil microorganisms and their utilization characteristics of six carbon sources. The results showed that the number of soil bacteria (P < 0.05) and actinomycetes (P < 0.001) decreased while the number of fungi (P < 0.001) and nitrogen-fixing bacteria (P < 0.01) increased significantly when different levels of N, P, and K were added. Additionally, the Pielou index (P < 0.001) of the soil microbial community decreased, and the Simpson index (P < 0.05) and McIntosh index (P < 0.001) increased with increasing N addition. This reduced the intensity of utilization of six carbon sources by soil microorganisms, especially the intensity of utilization of difficult carbon sources such as amines (P < 0.001), carboxylic acids (P < 0.001), polymers (P < 0.001) and other compounds (P < 0.001). The increase in P addition significantly reduced the Shannon index of soil microbial community (P < 0.05), while the increase in K addition significantly reduced the Shannon index (P < 0.05) and Pielou index (P < 0.05) of the soil microbial community and the intensity of utilization of two easily available carbon sources, carbohydrates (P < 0.001) and amino acids (P < 0.01), by the microbial community. In conclusion, N addition and K addition are the main factors affecting the functional diversity of soil microbial communities of P. macrophyllus. Attention should be paid to the cultivation of P. macrophyllus by applying fertilizer in small amounts and multiple times, reducing the addition of N and K, and appropriately increasing the addition of P to promote the growth of P. macrophyllus and its sustainable cultivation.
Subjects: Biology >> Botany >> Applied botany submitted time 2021-11-04 Cooperative journals: 《广西植物》
Abstract： There are poor conditions, and quite differences in seasonal climate environment in coastal sandy land, which makes it difficult for plants to survive. Ipomoea pes-caprae is an important sand-fixing plant widely distributed in coastal sandy land. In order to explore the adaptation mechanism of I. pes-caprae to environmental changes in different seasons, the seasonal variation of the leaves physiological traits were studied. In this paper, the contents of chlorophyll, the contents of osmotic substance, antioxidant enzyme activities, chlorophyll fluorescence parameters of the I. pes-caprae leaves in different seasons were measured, and the correlation analysis and principal component analysis were also carried out. The results were as follows: (1) Chlorophyll contents had the same trend with season changes, which was significantly higher in spring than that in summer, autumn and winter, but chlorophyll a/b had no significant change among seasons. (2) Fv/Fm and Fv/Fo of chlorophyll fluorescence parameters also had the same change trends, which were significantly higher in summer and winter than that in spring and autumn. (3) Proline content increased gradually with seasons, and reached the highest level in winter. Soluble sugar content in winter was significantly higher than that in other three seasons. However, there was no significant differences in malondialdehyde (MDA) content among seasons. (4) The activities of superoxide dismutase (SOD) and catalase (CAT) in spring were significantly higher than those in other seasons, but there was no significant differences in summer, autumn and winter. There was no significant differences in peroxidase (POD) activities among seasons. (5) There was a certain correlation between physiological indexes and climate factors by correlation analysis and principal component analysis. Temperature and sunshine significantly affected the contents of soluble sugar. Chlorophyll contents and antioxidant enzyme activities can better reflect the response of I. pes-caprae leaves to seasonal climate change. Therefore, the chlorophyll a/b can be kept stable by adjusting the contents of chlorophyll a and chlorophyll b, and meanwhile, the contents of osmotic adjustment substances and the activities of antioxidant enzymes can be improved to adapt to seasonal changes, among which photosynthesis and antioxidant enzymes were the key factors affecting its seasonal adaptability.
Subjects: Biology >> Botany >> Applied botany submitted time 2021-04-29 Cooperative journals: 《广西植物》
Abstract： Bhesa robusta is a kind of plant that is in imminent danger in China, which also is an important component of natural vegetation in the coastal ecotone of Guangxi. In order to learn about whether the light factor has the effects on the natural regeneration of B. robusta saplings or not, the interannual variation characteristics of physiological and growth indexes of B. robusta saplings under three different photosynthetic habitats of forest edge, forest gap, and understory; were studied. The results were as follows: (1) The deficiency of photosynthesis active radiation affected the growth of B. robusta saplings, The growth of ground diameter, plant height, and leaf area of understory saplings decreased significantly, while the growth index of saplings growing in the forest edge with sufficient light was the largest. (2) With the decrease of photosynthesis active radiation, the contents of antioxidant enzymes SOD and CAT, soluble protein, relative electrical conductivity, and MDA of the B. robusta saplings under forest edge habitat were significantly higher than in the understory habitat, the free proline content of B. robusta sapling under the understory habitat was significantly higher than under forest edge habitat. (3) With the decrease of light intensity, the photosynthetic pigment index chlorophyll-a, Chlorophyll b, caro-tenoids of Bhesa robusta sapling was increased in the understory habitat, and the chlorophyll a/b ratio of Bhesa robusta sapling was highest in the forest edge habitat. The net photosynthetic rate (Pn) and transpiration rate(Tr) on the photosynthesis physiological target of B. robusta saplings in understory habitat were lower than in forest edge and forest gap habitat; the intercellular CO2 concentration (Ci) and water use efficiency (WUE) of B. robusta sapling in the understory was higher than in forest gap and forest edge habitat. And WUE was the highest in the forest edge habitat from February to April, the water use efficiency (WUE) of B. robusta saplings in the understory habitat were higher than those of the other two habitats in June to October, and there are almost no differences between the three habitats in December. The light factor is one of the limiting factors during the growth period of B. robusta sapling. The growth of B. robusta sapling in the forest edge habitat was significantly better than that in the forest gap and understory habitat because of the abundant sunlight.
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