The effects of different storage temperatures (2, 4 and 8 ℃) and their corresponding optimal heat treatment conditions on the quality, physiological and biochemical indexes of Cucumber Fruits during storage were studied by using the quadratic regression orthogonal rotation combination design. The effects of different storage temperatures (2, 4 and 8 ℃) and their corresponding optimal heat treatment conditions on the chilling injury, hardness, weightlessness rate, polyphenol oxidase (PPO), catalase (CAT), peroxidase (POD), H₂O₂, super oxygen anion free radical (O^2-), ASA and GSH were determined. The results showed that heat treatment could inhibit chilling injury, while heat treatment combined with 4 ℃ low temperature storage could effectively inhibit the decline of fruit hardness and weight loss rate, delay the increase of peroxidase (POD) and polyphenol oxidase (PPO) activities, inhibit the increase of H₂O₂ and superoxide anion free radical O^2- and significantly inhibit the browning of cucumber, delay the decline of ascorbic acid and maintain the content of GSH, it was beneficial to adjust the balance of active oxygen system. The results showed that under the storage condition of 4 ℃, the hot water treatment condition of cucumber was 39.4 ℃ and 24.3 min, which could delay the senescence of cucumber fruit and better maintain the quality of cucumber fruit.

The wave effect and the shyness phenomenon in Alnus acuminata (Kunth) are crown parameters rarely studied, but important in the quality of the wood of standing trees, therefore, a morphometric modeling of the crowns of Alnus acuminata in homogeneous forests in the Sierra Norte de Puebla was carried out. In 20 rectangular sites of 1,000 m², the following were evaluated: total height (TA), normal diameter (ND), crown diameter (CD) and crown cover (CC). The Kruskal Wallis test was applied to data that did not meet the assumption of normality; for those that did, analysis of variance (ANOVA) was used, with Tukey mean comparison tests (α ≤ 0.05). The forest value index was 14.99, so its two-dimensional structure is normal based on DN, AT and CC. Its average slenderness index was 93.52, which makes the tree not very stable to mechanical damage. The life-space index was 38.92, which is high indicating that trees with low intraspecific competition developed better. At the canopy level, a pattern following an upward, oscillatory and constant wave effect was observed in groups of 10 trees. The shyness phenomenon showed an average crack opening of 27.39 cm between canopies, so this phenomenon is well defined for the species. It is concluded that in the crowns of Alnus acuminata, the wave effect is observed as a consequence of inequality in the acquisition of resources, and one way to minimize this inequality is through the phenomenon of botanical shyness.

Forest fire, as a discontinuous ecological factor of forest, causes the changes of carbon storage and carbon distribution in forest ecosystem, and affects the process of forest succession and national carbon capacity. Taking the burned land with different forest fire interference intensity as the research object, using the comparison method of adjacent sample plots, and taking the combination of field investigation sampling and indoor test analysis as the main means, this paper studies the influence of different forest fire interference intensity on the carbon pool of forest ecosystem and the change and spatial distribution pattern of ecosystem carbon density, and discusses the influence mechanism of forest fire interference on ecosystem carbon density and distribution pattern. The results showed that forest fire disturbance reduced the carbon density of vegetation (P < 0.05). The carbon density of vegetation in the light, moderate and high forest fire disturbance sample plots were 67.88, 35.68 and 15.50 t∙hm^-2, which decreased by 15.86%, 55.78% and 80.79% respectively compared with the control group. In the light, moderate and high forest fire disturbance sample plots, the carbon density of litter was 1.43, 0.94 and 0.81 t∙hm^-2, which decreased by 28.14%, 52.76% and 59.30% respectively compared with the control group. The soil organic carbon density of the sample plots with different forest fire disturbance intensity is lower than that of the control group, and the reduction degree gradually decreases with the increase of soil profile depth. The soil organic carbon density of the sample plots with light, moderate and high forest fire disturbance is 103.30, 84.33 and 70.04 t∙hm^-2 respectively, which is 11.670%, 27.899% and 40.11% lower than that of the control group respectively; the carbon density of forest ecosystem was 172.61, 120.95 and 86.35 t∙hm^-2 after light, moderate and high forest fire disturbance, which decreased by 13.53%, 39.41% and 56.74% respectively compared with the control group; forest fire disturbance reduced the carbon density of eucalyptus forest, which showed a law of carbon density decreasing with the increase of forest fire disturbance intensity. Compared with the control group, the effect of light forest fire disturbance intensity on the carbon density of eucalyptus forest was not significant (P > 0.05), while the effect of moderate and high forest fire disturbance intensity on the carbon density of eucalyptus forest was significant (P < 0.05).

Objective: The influence of climate on forest stands cannot be ignored, but most of the previous forest stand growth models were constructed under the presumption of invariant climate and could not estimate the stand growth under climate change. The model was constructed to provide a theoretical basis for forest operators to take reasonable management measures for fir under the influence of climate. Methods: Based on the survey data of 638 cedar plantation plots in Hunan Province, the optimal base model was selected from four biologically significant alternative stand basal area models, and the significant climate factors without serious covariance were selected by multiple stepwise regression analysis. The optimal form of random effects was determined, and then a model with climatic effects was constructed for the cross-sectional growth of fir plantations. Results: Richards formula is the optimal form of the basic model of stand basal area growth. The coefficient of adjustment  was 0.8355; the average summer maximum temperature  and the water vapor loss  in Hargreaves climate affected the maximum and rate of fir stand stand growth respectively, and were negatively correlated with the stand growth. The adjusted coefficient of determination  of the fir stand area break model with climate effects was 0.8921, the root mean square error (RMSE) was 3.0792, and the mean relative error absolute value (MARE) was 9.9011; compared with the optimal base model,  improved by 6.77%, RMSE decreased by 19.04%, and MARE decreased by 15.95%. Conclusion: The construction of the stand cross-sectional area model with climate effects indicates that climate has a significant influence on stand growth, which supports the rationality of considering climate factors in the growth model, and it is important for the regional stand growth harvest and management of cedar while improving the accuracy and applicability of the model.

Objective: To study the growth, accumulation and soil nutrient content of each overseeded species under different interharvesting intensity treatments of Eucalyptus, and to explore the best re-cultivation method suitable for mixed overseeded species after Eucalyptus interharvesting. Methods: In Guangxi state-owned Qipo forest, Eucalyptus tailorii with different planting densities (DH32-29) were mixed with Castanopsis hystrix, Mytilaria laosensis and Michelia macclurei, and four different treatments (CK, LT, MT and HT) were established for re-cultivation of Eucalyptus near-mature forests with different logging intensities, and the differences in growth conditions and soil physicochemical properties of each species were analyzed. Results: (1) As the proportion of Eucalyptus allocation decreased, the growth of Eucalyptus diameter at breast height, tree height and individual wood volume could be promoted; the growth of the three parameters of HT and MT Eucalyptus were significantly different from LT and CK. (2) The average wood volume per plant of the set species in the CK and LT treatments was Mytilaria laosensis > Michelia macclurei > Castanopsis hystrix, while in the MT and HT treatments it was Mytilaria laosensis > Castanopsis hystrix > Michelia macclurei. (3) The differences in soil aeration, total saturated water holding capacity, capillary water holding capacity, and field water holding capacity in soil layers of different depth varied. In the same soil layer, soil aeration, total porosity and capillary porosity were HT > CK > LT > MT; saturated water holding capacity and capillary water holding capacity were HT > CK > LT > MT, while field water holding capacity was CK > HT > LT > MT. (4) Organic matter, pH, total nitrogen, total phosphorus, total potassium, fast-acting nitrogen, fast-acting phosphorus, and fast-acting potassium changed with varying soil depth in each treatment.

Magnetite magnetic nanoparticles (MNP) exhibit superparamagnetic behavior, which gives them important properties such as low coercive field, easy superficial modification and acceptable magnetization levels. This makes them useful in separation techniques. However, few studies have experimented with the interactions of MNP with magnetic fields. Therefore, the aim of this research was to study the influence of an oscillating magnetic field (OMF) on polymeric monolithic columns with vinylated magnetic nanoparticles (VMNP) for capillary liquid chromatography (cLC). For this purpose, MNP were synthesized by coprecipitation of iron salts. The preparation of polymeric monolithic columns was performed by copolymerization and aggregation of VMNP. Taking advantage of the magnetic properties of MNP, the influence of parameters such as resonance frequency, intensity and exposure time of a OMF applied to the synthesized columns was studied. As a result, a better separation of a sample according to the measured parameters was obtained, so that a column resolution (R_s) of 1.35 was achieved. The morphological properties of the columns were evaluated by scanning electron microscopy (SEM). The results of the chromatographic properties revealed that the best separation of the alkylbenzenes sample occurs under conditions of 5.5 kHz and 10 min of exposure in the OMF. This study constitutes a first application in chromatographic separation techniques for future research in nanotechnology.