| Camellia oleifera(Camellia oleifera Abel.)is an important edible woody in China.The development of Camellia oleifera industry requires good species and seedlings as material basis and preconditon,while the scientific and rational evaluation of seedling quality is an important means to guarantee good species and seedlings.However,quality classification of seedlings in the production of Camellia oleifera is usually based on a few morphological indexes such as seedling height and ground diameter,which makes it difficult to accurately reflect the physiological level of seedling quality,and also leads to excessive fertilizer and water management due to sheer pursuit of seedling height and ground diameter growth in the cultivation of Camellia oleifera seedlings.Thus,this causes problems such as insufficient lignification,poor adaptability and resistance,low afforestation survival rate and poor performance in the later stage of nursery seedlings transplanted from the nursery,seriously affecting the quality of new afforested Camellia oleifera.The experiment takes biennial container seedlings of the mainly planted Camellia oleifera varieties,namely,"Huashuo","Huajin","Xianglin No.1" and "Xianglin 210",as the research subjects,tests and analyzes their morphological and physiological indexes which affects seedling quality of Camellia oleifera.It delves into the classification method of seedling quality which combines morphological and physiological indexes,and tests and observes the growth performance of seedlings of different quality levels after planting and growth,providing scientific basis and technical method for comprehensive evaluation of seedling quality of Camellia oleifera.1.On the premise of normal distribution,standard deviation method is used to partition four varieties of Camellia oleifera seedlings and build a seedling partition standard with seedling height and ground diameter as indexes.The seedlings are partitioned into Section Ⅰ seedling,Section Ⅱ seedling,Section Ⅲ seedling and SectionⅣ seedling,while the sample amount of later-stage index measurement and planting and growth of seedlings are reduced and the randomly selected samples are more accurate.2.Analysis and comparison of morphological indexes of Camellia oleifera seedlings finds significant differences of total root length,root surface area,root volume,total number of root tips and number of stem nodes in different sections of the 4 varieties of Camellia oleifera,all progressively decreasing from Section Ⅰ seedling,Section Ⅱ seedling,Section Ⅲ seedling to Section Ⅳ seedling,with a significant difference between Section Ⅰ seedling and Section Ⅳ seedling.Based on the correlation analysis of root indexes,it is believed the total root length can reflect root quality on a relatively comprehensive basis.3.The analysis and comparison of the physiological indexes of Camellia oleifera demonstrate no significant differences in physiological indexes,except soluble sugar content and root activity,of "Huashuo ","Huajin","Xianglin No.1" and "Xianglin 210".There is no significant difference in relative leaf water content and chlorophyll content in different sections of four varieties of Camellia oleifera seedlings.The soluble sugar content,soluble protein content and root vigor of the four varieties of Camellia oleifera shows a decreasing trend from Section Ⅰ seedling,Section Ⅱ seedling,Section Ⅲseedling to Section Ⅳ seedling,while the malondialdehyde content presents an increasing trend from Section Ⅰ seedling,Section Ⅱ seedling,Section Ⅲ seedling to Section Ⅳ seedling.The analysis of variance demonstrates significant differences among different sections.The correlation analysis of morphological and physiological indexes of Camellia oleifera seedlings shows a close changing correlation between seedling form and root vigor of Camellia oleifera,both with a significantly positive correlation.4.After the planting and growth of Camellia oleifera seedlings,the observation of the growth finds significantly different growth performance of the seedlings after planting and growth.Growth amount of tree height and ground diameter,number of effective buds and individual tree leaves are highest in Section Ⅰ Seedling and lowest in Section Ⅳ Seedling.After the planting and growth of 270d,the survival rates of Camellia oleifera seedlings in different sections are significantly different,with the survival rate of Section Ⅰ Seedling averagely above 86.6%,while Section Ⅳ Seedling averagely below 74%.5.According to the results of principal component analysis and considering the operability in the practical measurement,except seedling height and ground diameter,root system is a key index to be considered to be added,and total root length,number of stem nodes and root vigor can be selected as key indexes for seedling quality evaluation.The comprehensive evaluation results show a highest comprehensive score in Section Ⅰ Seedling,followed by Section Ⅱ Seedling,Section Ⅲ Seedling and SectionⅣ Seedling.This is consistent with the results of growth and planting of seedlings.Based on this,the quality of Section Ⅰ Seedling meets the standards of transplanting from the nursery and can be directly used for afforestation,Section Ⅱ Seedling and Section Ⅲ Seedling share a relatively high quality and can be kept in the nursery for continued cultivation of as 3-year-old seedlings,while Section Ⅳ Seedling,with a poor performance,is recommended to be abandoned. |
