To study the physiological characteristics of high light efficiency in cassava cultivar Ku50, W14, a wild type, wild relatives of A4047 and cultivated species of Ku50 were used as the materials to investigate the character of photosynthetic physiology during different varieties of cassava by measuring the photosynthetic pigment content on functional leaves, net photosynthetic rate (including the photosynthetic rate curve under different light intensity and photosynthetic daily variation) and chlorophyll fluorescence parameters (including mainly the actual photosynthetic efficiency of PSⅡ-Y(Ⅱ), and non-photochemical quenching-NPQ). The result showed that the content of various photosynthetic pigments in Ku50 was significantly higher than that in W14, but no significant difference with that in A4047, suggesting that Ku50 and A4047 may have higher photosynthetic carbon fixation capacity. The net photosynthetic rate of Ku50 was slightly higher than that of A4047 and much higher than that of W14 on the photosynthetic daily variation and Ku50 and A4047 had no obvious midday photoinhibition phenomenon while W14 had, suggesting that Ku50 and A4047 may have higher light conversion efficiency and stronger resistance to high light. The photosynthetic rate curve under different light intensity showed that three varieties of cassava all did not arrive the light saturation point up to the maximum light intensity of 2500 μmol/(m²·s), and the net photosynthetic rate also showed Ku50>A4047>W14. Among them, Ku50 was about 40 μmol/(m²·s), A4047 was about 34 μmol/(m²·s), but W14 was only about 15 μmol/(m²·s). This result was consistent with photosynthetic daily variation and also suggested that Ku50 had stronger resistance to high light and higher light energy conversion efficiency. In addition, the chlorophyll fluorescence parameters were measured to analyze the absorption, distribution and utilization of light energy in different varieties cassava. The result showed that under high light the Y(II) of Ku50 was significantly higher than that of W14, but slightly higher than that of A4047 which had no significant difference (P>0.05). And the NPQ of Ku50 was significantly lower than those of W14 and A4047, indicating that the light energy dissipated into heat on Ku50 was lower than those of W14 and A4047, which in turn proved that the light energy conversion efficiency of Ku50 was higher than those of W14 and A4047, and which was consistent with the results of photosynthetic pigments content and net photosynthetic rate. In conclusion, this research proved that high light efficiency in cassava cultivar Ku50 was induced by high light, and had higher tolerance and utilization rate to high light than wild type of W14 and wild relatives of A4047.

In this experiment, seven different camellia plants were used as rootstocks and four different camellia scions to form 28 combinations, to screen the stocks-scion combination and study the grafting affinity, and to measure and analyze grafting experiment indicator that is the survival rate, preservation rate and growth traits of grafted seedlings, to investigate the growth status of grafted seedlings after 18 months. The relationship between grafting anvil, soluble sugar content and graft compatibility was evaluated. The result showed that the grafted survival rate and preservation rate of Camellia gigantocarpa Hu grafted with C. rosmannii and C. achrysantha scion were more than 90%, and the grafting survival rate and survival rate of scions reached more than 80% when C. gigantocarpa Hu grafted with C. chrysantha,, it is proved that C. gigantocarpa Hu is the best rootstock for grafting affinity. The grafting seedlings of C. japonica Heimudan and C. rosmannii had a preservation rate was 6.67%, the preservation rate of C. japonica Heimudan and other 3 kinds of scion was 0, it is proved that C. japonica Heimudan had the worst affinity as rootstock. The scions of C. achrysantha and C. rosmannii had better affinity with different rootstocks. The grafting survival reached more than 90%when C. achrysantha was grafted with C. semiserrata, C. hirsuta, C. japonica Heimudan, C. gigantocarpa. The grafting survival reached more than 90% when C. rosmannii grafted with C. gigantocarpa and C. amplexicaulis. The grafting survival reached more than 80% when C. rosmannii grafted with C. semiserrata and C. polyodonta. Grafting affinity is related to the soluble sugar content of stocks-scion. Closer sugar content of stocks-scion leads to the ratio is closer 1 and the higher grafting survival rate will be. C. gigantocarpa/C. achrysantha, C. hirsuta/C. achrysantha, C. amplexicaulis/C. rosmannii, C. gigantocarpa/C. rosmannii, C. gigantocarpa/C. chrysantha were found to be the excellent combinations by principal component analysis.

The harvested Newhall navel orange fruits are easy to quality deterioration and spoilage, which seriously affecting the commodity value and shelf-life. Kadozan, a novel commercial liquid chitosan formulation, can be conveniently used for fresh produce postharvest treatment by diluting Kadozan to the required concentration with water. The influences of Kadozan with dilution of 1∶800 (V_Kadozan∶V_{Kadozan+water}) on the storage quality and storability of Newhall navel orange fruit were investigated. Postharvest Newhall navel oranges were immersed with distilled water (the control) and chitosan for 5 min, respectively, and then stored at (18±1)℃ and 80% relative humidity. During the storage, the samples were taken every 30 days to determine the rate of commercially acceptable fruit, the percentage of weight loss, respiration rate, fruit appearance color characteristics, the contents of chlorophyll and carotenoid in pericarp, and the contents of pulp nutrients. Compared with the control fruits, during storage, chitosan (Kadozan) treatment could reduce fruit weight loss, fruit respiration rate, retain higher rate of commercial acceptable fruit, higher contents of pericarp chlorophyll and carotenoid, higher values of pericarp L^*, b^* and h°, but lower values of pericarp a^* and citrus color index (CCI). In addition, Kadozan treatment could maintain higher contents of soluble solids (TSS), titratable acid (TA), soluble total sugar, sucrose, vitamin C, carotenoids, flavonoids and total phenol in the pulp of Newhall navel orange during storage. When stored for 120 d, the rate of commercially acceptable fruit and the percentage of weight loss in Kadozan-treated oranges was 95.56% and 4.39%, respectively. From the above data, it is concluded that the treatment of chitosan (Kadozan) can improve the storability and maintain the better quality of postharvest Newhall navel orange fruit, indicating the dilution of 1:800 (V_Kadozan∶ V_{Kadozan+Water}) could be a safe and facile approach to maintain the quality and extend the shelf life of Newhall navel orange after harvest.

The study of the leaf anatomical structure of macadamia germplasm resources and its drought resistance was aimed to provide theoretical basis for macadamia seed breeding, introduction and cultivation. 11 leaf anatomical parameters of 20 macadamia germplasm resources were analyzed and compared using paraffin section technique. The drought resistance of different germplasm resources was comprehensively evaluated by the principal component analysis, membership function method and systematic clustering method. The results showed that macadamia leaves were typical leaves with different faces, and there were significant differences among the anatomical structure indexes of different germplasm resources (P<0.01). Principal component analysis showed that the order of the eleven indexes reflecting the drought resistance of macadamia was thickness of palisade parenchyma thickness>leaf thickness>cell tense ratio>palisade/spongy tissue>sponge ratio>upper cuticle thickness>lower epidermis thickness>upper epidermis thickness>lower cuticle thickness>midrib thickness>spongy parenchyma thickness. According to the membership function method and the weight of each index, the order of drought resistance of the 20 macadamia germplasm resources was as follows: No. 1>No. 19>No. 5>No. 10>No. 14>No. 11>No. 16>No. 7>No. 2>No. 20>No. 8>No. 13>No. 18>No. 15>No. 9>No. 3>No. 6>No. 4>No. 17>No. 12. After "Z-score" standardization, the 20 germplasm resources were classified into 3 groups at 15 genetic distances. No. 1, No. 5, No. 10, No. 11, No. 14, No. 16 and No. 19 had thicker leaves, developed palisade tissue, higher palisade/spongy tissue and cell tense ratio than other germplasms, and had higher water retention and photosynthetic capacity, so they were high drought-resistant groups. The leaves, epidermis and cuticle of No. 3, No. 4, No. 6, No. 9, No. 12, No. 15 and No. 17 were thin, and the leaves were relatively loose, showing low drought resistance, so they were low drought resistance groups. The drought resistance of other germplasms was in the middle.

Based on specimen diagnostics and literature studies, six new records of Angiosperm in Guizhou Province were reported, namely Lepidium didymum L. (Brassicaceae), Lactuca serriola L. (Asteraceae), Dactylicapnos lichiangensis (Fedde) Hand.-Mazz. (Papaveraceae), Dinetus duclouxii (Gagnep. & Courch.) Staples (Convolvulaceae), Zingiber atrorubens Gagnep. (Zingiberaceae), Carex phyllocephala T. Koyama (Cyperaceae). Main morphological identification characteristics, distribution descriptions, voucher specimens and photographs were provided for all species, and the systematic position changes of some species were also discussed. The voucher specimens were deposited in the Herbarium of the Natural Museum of Guizhou University (GACP).

Dendrobium sinense is a tropical plant endemic to Hainan Island with great ornamental and medicinal values. However, unascertained reference genes restrict the quantitative analysis of gene expression in the species. In this study, using our previous transcriptome data of D. sinense, the 164 candidate genes were identified with low variance (CV≤0.2) and moderate expressions (TPM between 10-300). By GO clustering, 24 candidate genes were selected from different functional groups to avoid the effect of co-expression on further stability analysis. In order to avoid the false positive of genomic DNA that may remain in the template during RT-qPCR amplification, primers across introns were designed in this study, and amplification primers that met the requirements of 15 candidate reference genes were screened by electrophoresis. To ensure the specificity of RT-qPCR amplification, LightCycler 96 was used for melting curve analysis. According to the RT-qPCR data of 15 candidate genes, four tools were used to evaluate the expression stability. The results of multiple algorithm analysis showed that CLP1 & SEC23, SEC23 & CPY71, CLP1 & SEC23 and RNG1L & PECT were the best reference genes under drought stress. After comprehensive sorting, SEC23 and CLP1 were selected as the most stable reference genes under drought stress. In different tissues of D.sinense, ADF11 & IBR5, PRP19 & CLP1, ADF11 & CLP1, ACBP2 & IBR5 were identified as the best reference genes, respectively. After comprehensive analysis, ADF11 and ACBP2 were identified as the most stable reference genes in different tissues. Combined with the above drought stress and different tissue analysis data, IBR5 and CPY71 were finally determined as stable reference genes under comprehensive conditions. The validation of internal reference genes showed that compared with the traditional Actin internal reference, the internal reference genes screened in this study could obtain more accurate RT-qPCR calibration results, indicating that the generated internal reference genes had extremely high stability. In summary, this study provides ideas for identifying stable reference genes using transcriptome data. For the first time, stable reference genes were identified in the whole genome of D.sinense, which laid a foundation for further study of gene expression and function.

Potato is the fourth largest food crop in the world, but little research has been done on this crop about rice husk mulching and copper (Cu). Rice husk is a by-product of rice processing and has great potential to reduce environmental pollution. Plastic film mulching gives us a non-negligible problem of environmental pollution, and even crop yields will be affected. Compared with black film, it has the advantages of wide source, lower cost and no need for recycling, which can basically be used locally. Previous studies have shown that the photosynthetic pigment content, photosynthetic rate, nutrient content, plant height, stem thickness, tuber number, above ground dry weight and yield of potato plants were enhanced by both Cu solution dip treatment and foliar spray of Cu. In this experiment, the accumulation and distribution of Cu in potato plants under different mulching patterns were investigated by using potato "Favorita" as the material and three mulching patterns: bare ground (CK), rice husk (6 000 kg/hm²) mulching (DK) and black film mulching (HM) for winter cultivation in the field. The results showed that the accumulation of Cu in stems and leaves showed a trend of increasing and then decreasing under different mulching patterns, while the accumulation in tubers and whole plants showed a trend of gradually increasing. The accumulation of Cu in stems and leaves ranged from 13.45%~17.70% and 82.30%~86.55% of the whole plant 10 d after full seedling emergence to 2.99%~3.53% and 8.40%~10.56% 58 d after full seedling emergence, respectively. The accumulation of tubers increased from 26.76%~29.60% 22 d after full seedling emergence to 85.91%~88.68% 58 d after full seedling emergence. The Cu accumulation of plants under DK treatment was generally higher than that of LD and HM treatments in the whole growth period. The Cu accumulation of plants under DK treatment was 38.01%, 80.92%, 40.24%, 72.45% more than that of CK treatment in stem, leaf, tuber and whole plant respectively, and 92.21%, 47.22%, 48.12%, 45.16% higher than than that of the HM treatment, respectively. The accumulation of Cu in potato plants 10 d after full seedling emergence was positively correlated with the accumulation of Cu at the later stage, and the accumulation of Cu in stems and leaves was also positively correlated with the yield until 58 d after full seedling emergence. The difference in accumulation by site is due to the fact that in the early growth period, when potato plant is still in the seedling stage, stems and leaves are the sites of Cu accumulation. As the plant grows, tubers are gradually formed. About 31 days after full seedling emergence, the growth of stems and leaves gradually slow down, while the tubers are in the growth phase. At this time, the accumulation center shifts to the tuber, from stems and leaves, which shows that the accumulation of stem and leaves gradually decreases, while the accumulation of tuber continues to increase. The reasons for the higher accumulation of DK than CK and HM may be as follows. First, rice husk, on the other hand, can not only act as a thermal insulation layer to isolate strong external heat, but also improve soil water storage efficiency, increase soil water content, and have significant effects in reducing soil temperature. Second, rice husk can increase soil organic carbon content after being degraded as exogenous organic matter, and the study found that the soil available Cu content was significantly and positively correlated with soil organic carbon content. The experiment showed that under the test conditions, the accumulation of Cu by potato plants could be effectively increased under rice husk mulching at 6000 kg/hm² level.

Breadfruit is considered as the most potential food crop to solve tropical famine with high economic value. Breadfruit was introduced from several countries, and there are no research on the systematic taxonomic and genetic diversity analysis about it. The objective of this study was to specify the genetic distance and relationship among breadfruit and its closest wild relatives. For genetic diversity analysis, 33 pairs of SSR primers with clear amplified bands, high polymorphism and good stability were selected from 75 pairs of SSR primers. PCR amplification was performed, and the products were detected by 8% denaturing polyacrylamide gel. Genetic diversity correlation analysis was performed by NTSYS software. The results showed that the polymorphism ratio of amplified bands of the 33 SSR markers was 94.57%. 199 number of polymorphic sites were detected, with an average of 6.030 per marker. The PIC values of the SSR markers ranged from 0.623 to 0.940, with an average of 0.865. The genetic similarity coefficients among the breadfruit resources ranged from 0.517 to 0.951, with an average genetic similarity coefficient of 0.685. Furthermore, germplasm ZZP possessed the greatest variation among individuals, with an average genetic similarity coefficient of 0.626. Germplasm XYS1-3 possessed the least variation among individuals, with an average genetic similarity coefficient of 0.723. At the genetic similarity coefficient of 0.713, the 30 breadfruit resources were clustered into five groups, with XBL and breadnut type I (ZZP, LX, STH, HJ5) which used for landscaping clustered into one group, breadfruit SLLK, XYS2, XYS3, XYS5, XYS6 and YN clustered into one group, breadnut type Ⅱ SLM2, YDNXY1, G1 and G2 clustered into one group, breadnut type Ⅱ W1, W3, SMY, 8-4, 8-3, 5-5 and 5-6 clustered into one group. The three-dimensional diagram could better distinguish XBL and breadnut type I ZZP, LX, STH, HJ5 from the breadfruit and breadnut type Ⅱ resource with edible value. Based on the cluster analysis, we speculated that XYS2, XYS3, XYS5 and XYS6 might be introduced from Vietnam, XYS1-3, YBG and XYS1 might be introduced from Indonesia. Furthermore, FJ was regarded as a breadfruit germplasm. The present study reported the genetic diversity of breadfruit resources in China firstly, and elucidated the genetic relationship among breadfruit resources. In addition, the results could provide theoretical basis for variety breeding and identification of breadfruit complex.

Sugarcane plantations are mainly distributed in mountainous areas with high land fragmentation and complex cropping structure in Yunnan Province. Frequent cloud cover reduces the good observations of the land cover by using optical remote sensing. So it is difficult to extract sugarcane plantations with a high accuracy based on satellite optical remote sensing data. Xinping Country, a typical mountainous sugarcane plantation region, was chosen to explore a suitable method for the extraction of sugarcane plantations in mountainous areas. In this study, Landsat-8 and Sentinel-2 optical imagery for Xinping from October 1, 2019 to July 1, 2021 were used as the main data sources, and the DEM data and field survey data were used as the auxiliary data. The synthetic time-series images with high spatial-temporal resolution were constructed on Google Earth Engine (GEE). Firstly, we analyzed the differences among sugarcane and evergreen vegetation, water body, impervious, and other crops in spectral index characteristics, phenological characteristics, and topographic characteristics. Secondly, we determined the optimal thresholds for extracting sugarcane plantations for the four phenological parameters including rise time, fall time, above integral of season and below integral of season, as well as elevation and slope factors based on the training samples. Thirdly, we mapped the sugarcane plantations of 2020 and the mapping accuracy was verified using the validation samples in the study area. Finally, the spatial distribution of sugarcane plantations was analyzed at town scale. The results showed that synthetic time-series images based on the Landsat-8 and Sentinel-2 optical imagery could increase the number of good observations in the study area and improve the spatial resolution of the images, which could solve the problem of low quality of remote sensing images in mountainous areas and could better monitor phenological characteristics and seasonal changes of vegetation. The resultant 2020 sugarcane map had overall, user and producer accuracy of 97.07%, 88.85% and 80.57%, respectively with the Kappa coefficient of 0.83. According to the annual sugarcane map in 2020, there was a total of 7705 hm² sugarcane in Xinping, there were more sugarcane distribution in the southeast than in the northwest, as well as the southeast terrain was lower than that in the northwest. There were significant differences in the area of sugarcane plantations between townships, the township with the largest sugarcane plantation area is Mosha Town (2786 hm²) and the township with the smallest sugarcane plantation area is Gucheng district (0.87 hm²), which is consistent with the actual research. The sensitivity analysis of phenology parameters for sugarcane mapping demonstrated that the four parameters including rise time, fall time, above integral of season, and below integral of season are all important to improve the user accuracy and reduce the commission errors in the sugarcane mapping. The sugarcane plantation mapping algorithm proposed in this study could provide a reference for the extraction of sugarcane plantations in the complex landscapes of mountainous areas in the future.

Polyploidy can be accompanied by some super character, such as enhanced stress resistance, larger organ size, and increasing biomass. Polyploidy provides an important way for cassava varieties breeding. The single-node axillary buds of cassava variety SC12 were used as the explants to observe the effect of the different colchicine concentrations on autotetraploid induction rate. The morphology, anatomy and agronomic characteristics of autotetraploid and the diploid parents were compared. The highest efficiency of inducing autotetraploid of SC12 was 7.78% at the concentration of 0.03 g/L colchicine. The ploidy of 20 plants was identified by the flow cytometry and chromosome numbers counts in root tip cells. Consequently, a total of 11 tetraploid plants as well as 5 chimeric plants were obtained. Positive autotetraploid cassava lines accounted for 55% of all the tested lines, and the variation rate was 80% of the tested lines. Significant differences in morphology and anatomy were observed between the autotetraploid and the diploid parents. In morphology, the tetraploid plants became shorter, the stem became thicker, the leaf tip became shield, the leaves changed from lanceolate to arch, the cleft leaf length/cleft width decreased significantly, and the chlorophyll content increased significantly. The length, width and chloroplast number of tetraploid guard cells was significantly increased by 2.33%, 28.99% and 117.79%, respectively, compared with that of diploid parent. Stomatal density was decreased by 40.06% compared with the control. The guard cells of tetraploid variant were oval, while those of diploid variant were cylindrical. The leaf thickness and palisade tissue thickness of tetraploids were significantly higher than those of diploids, and increased by 24.41% and 43.88% compared with the control, respectively. The palisade tissue/sponge tissues of autotetraploid plants were 1.9 times as large as the diploid line, indicating that the palisade tissue of tetraploid leaves was closely arranged, but the spongy tissue was not well developed. The results of yield detection showed that the tubers weight per plant and harvest index of polyploid line SC12-11 was 3.30 kg and 0.43, respectively, which was significantly higher than that of the control.