造林用苗木质量评价研究进展综述

在阐述苗高、根体积、矿质营养等形态、生理和活力指标的基础上,综述了20世纪80年代以来国内外苗木质量评价研究情况,提出苗木质量评价应坚持分阶段、多指标、动态评价的原则,并用造林数据验证苗木质量调控技术,旨在为苗木质量研究提供参考。     

苗木质量评价的研究现状与趋势

如何正确评价苗木质量的问题正受到普遍关注。本文对苗木质量评价的研究现状做了简要介绍。评价苗木质量的指标主要有苗木水分状况,矿物质含量,碳水化合物储量,芽休眠状态,形质指标,根生长潜力,抗冻性和抗逆性等。文章对以上指标的测定方法及各自的特点做了简述,并分析了存在的问题与发展方向。     

苗木活力评价指标及体系研究述评

苗木形态指标、生理指标和苗木活力的表现指标是评价苗木质量的3个主要方面，作者重点阐述了当前国内外学者对苗木活力评价指标及其体系的研究，包括直接指标和间接指标的研究，并对其研究及发展的历程进行了简明扼要的论述。     

评价出圃苗木质量的几个主要指标

出圃苗木质量的优劣关系着造林的成与败,质量优良的苗木,有利于达到速生丰产优质的指标。虽然刘勇等人提出了用苗木的形态指标(苗高、地径、高径比、苗木重量、根系、茎根比等)、生理指标、生长表现指标评价苗木质量,但由于这些指标有些易于观察、掌握,有些则受检验条件和技术要求的限制难以把握。所以,如何利用易测的苗木形态指标快速确定苗木质量,则是生产部门急需解决的课题。现结合多年的观察和实践,就几项可行,易于操作和观察的苗木形态评价指标简介如下。     

侧柏苗木主要生理指标的研究

侧柏1年生苗在不同程度的干旱胁迫下,根水势、须根外渗液电导率、细胞膜破损率、须根导电能力和造林成活率都发生了变化,经测定和分析,作者认为:苗木根水势、须根外渗液电导率和导电能力在反映苗木质量方面是一致的,能够准确地评价苗。本的生命活力,可以作为评价侧柏苗木质量的生理指标。并认为,应用BLY植物组织活力测定仪测定苗木须根的导电能力,是测定苗木生理活性的简便方法。     

苗木生理与质量研究进展

综述了矿质营养、碳水化合物含量、水分状况、生长调节物质含量、耐寒能力等苗木生理状况与质量的关系。对根生长势、电阻抗等10种苗木质量生理指标的测定方法作了简要介绍。     

现代苗木质量评价的生理指标

本文对苗木质量评价的生理指标进行了系统论述，指出现代苗木质量评价的生理指标主要有苗木水份、矿质营养、碳水化合物、导电能力、叶绿素含量、根系活力、芽休眠及其他生理指标。论述了各生理指标的作用、重要性和研究现状及方向。     

国外松壮苗培育技术总结

本文综述了国外松苗木质量的评价因子,对几项育苗技术试验结果进行总结,种子大小和重量与种子发芽速度相关,早发芽幼苗在苗床上拥有生长空间优势,经种子分级,采用大,中粒种子育苗能够提高苗木质量,根据苗木质量评价和造林表现及育苗经济综合分析,提出国外松适宜的育苗密度为１１０－１４０株／ｍ＾２苗木切根改善根系质量和苗木结构,显著提高造林成活率和改善苗木生长,在亚热带地区,宜在８－１０月份实施２－３次,深度１     

出圃苗木质量评价的几个主要指标

出圃苗木质量的优劣关系着造林的成与败。质量优良的苗木，有利于达到速生丰产优质的指标。虽然有人提出了用苗木的形态指标（苗高、地径、高径比、苗木重量、根系、茎根比等）、生理指标、生长表现指标评价苗木质量，但由于这些指标有些易于观察、掌握，有些则受检验条件和技术要求的限制难以把握。     

世界苗木质量研究的进展和趋势

从苗木质量概念、质旺评价研究的发展现状及未来发展方向出发，概要地综述了国际上有关研究所取得的成就。鉴于我国苗木质量研究和评价与国际先进水平存在的巨大差距，提出了由林木生理学家全面参与，国有林业企业积极配合，有计划地开展以提高根生长潜力为中心的全面控制苗木质量的苗木培育学研究。     

Predicting field performance using seedling quality assessment

Seedling quality is defined as fitness for purpose. Attributes for assessing seedling quality are grouped in material attributes that can be rapidly assessed by any number of direct or indirect methods, and performance attributes that are assessed by subjecting whole seedlings to certain environmental regimes and evaluating their growth response. Material attributes comprising morphology, bud dormancy, water relations and nutrition and performance attributes comprising frost hardiness, vigour and root growth potential are discussed with regard to relevance for predicting field performance. Measurement techniques and relevance in assessing seedling quality are presented for different physiological attributes: electrolyte leakage, enzymatic activity, water potential, water conductance, mineral nutrition, food reserves, mitotic index, gas exchange, chlorophyll content, plant growth regulators, stress-induced volatile emission, and nuclear magnetic resonance. Methods with future potential in improving the prediction of field performance are identified and discussed. The methods presented in this respect are chlorophyll fluorescence, infrared thermography, machine vision systems, integrated approaches and ecophysiological evaluations.     

Prediction of planted seedling survival of five Mediterranean species based on initial seedling morphology

Field performance can be predicted by evaluating nursery stock quality, but optimal morphological variables for use in these assessments may vary by species especially under dry Mediterranean conditions. Our objective was to identify initial seedling morphological characteristics that successfully predict field performance of five Mediterranean species (Pinus halepensis, Quercus ilex, Quercus coccifera, Ceratonia silqua and Pistacia lentiscus). Container seedling morphology was evaluated following the nursery phase, and then seedlings were outplanted in the field where field survival was monitored for two successive years. Results indicate that survival can successfully be predicted from seedling initial morphological characteristics for all these species, yet not all the initial characteristics were good predictors. Survival of P. halepensis and Pist. lentiscus seedlings was positively correlated to initial seedling root-collar diameter, total dry weight and Dickson’s quality index, and can be reliably predicted by these variables. In contrast, seedling field survival of the two Mediterranean evergreen oak species was correlated with few initial morphological attributes; initial diameter provided an accurate index to predict second-year outplanting survival for both species while height/diameter was a good survival predictor for Q. coccifera seedlings. For C. siliqua seedlings, seedlings with larger initial diameter and total biomass survive better in the field. Thus, diameter was the common variable that accurately predicted survival for all species, which should be >5 mm for P. halepensis seedlings and >7 mm for the remaining species.     

Quantifying root system quality of nursery seedlings and relationship to outplanting performance

With over 1.5 billion forest tree seedlings produced annually in the USA, seedling quality assessment is critical to ensure reforestation success. While height and root-collar diameter are the most common traits evaluated during seedling quality assessment, above-ground morphology is not always an accurate predictor of performance after outplanting. Root system morphology and physiological status may provide a more accurate indication of seedling potential. However, relatively few studies have attempted to quantitatively assess root system quality in relation to outplanting success. Large root volume, high root fibrosity, and an increased number of first-order lateral roots have shown some correlation to improved field performance. Physiological seedling quality assessment is commonly practiced through evaluation of root growth potential. Other tests, such as root electrolyte leakage, have also shown some potential as measures of seedling physiological quality. This review identifies current methods of assessing seedling root system quality and discusses potential shortcomings of these methods. An increased understanding of the suitability of current tests, coupled with the development of new tests and multiple parameter relationships, may foster the development of species and site-specific targets for seedling root system quality assessment. The production of seedlings with root systems that meet high morphological and physiological standards better enables seedlings to rapidly establish and thrive upon outplanting.     

不同种源旱冬瓜苗期生长量的地理变异研究

通过对滇西南地区15个县的0.5年生旱冬瓜种源的苗高、地径进行调查分析,研究了不同种源旱冬瓜苗高、地径的生长变异及其与地理环境因子的关系,利用苗高和地径2个因子进行逐步聚类分析。结果表明,各种源间在苗高、地径生长上均表现出极显著的差异,苗高生长表现最好的是孟连种源,平均苗高达31.4 cm;地径生长表现最好的种源是勐海种源,平均地径为0.38 cm。环境因子及地理因素对旱冬瓜种源的遗传变异有影响,苗高、地径与各种源原产地的地理经度呈负相关;采用种源间苗高、地径进行逐步聚类分析,15个种源可分为5类,根据各种源苗期苗高、地径的生长状况,初步筛选出瑞丽、孟连2个优良种源。     

An overview of Ontario's Stock Quality Assessment Program

Since 1992, the Stock Quality Assessment Program at the Ontario Forest Research Institute (OFRI) has offered seedling physiological testing services to foresters and nursery managers. The purpose of this program is to improve nursery stock quality and plantation performance by developing and applying procedures for assessing the physiological quality of nursery stock. Two levels of testing are available: Seedling Certification and Problem Stock Testing. Testing at both levels involves a visual assessment, measurement of chlorophyll fluorescence of the foliage and root growth potential. Applying these tests has directly improved plantation establishment between 1992 and 1995 by preventing over 3 million damaged seedlings from being planted, at an estimated regeneration cost savings of over $2 million (Can). Consideration of cost-benefits for both direct and indirect values demonstrates the merits of a stock testing program. Testing has been conducted either at OFRI or at a private lab, providing clients with an impartial assessment of their stock. Consistent test results, comparable from year-to-year and between laboratories, are achieved by the use of controlled environment testing, trained personnel and duplicate testing on selected stocklots. A database comprised of physiological test information for over 1100 stocklots provides a basis for comparing and ranking seedlings grown throughout the province. This database may be used to refine operational nursery practices, to evaluate changes in seedling quality over time, and to relate seedling quality to field performance.     

Why seedlings survive: influence of plant attributes

Seedling survival and successful forest restoration involves many silvicultural practices. One important aspect of a successful forest restoration program is planting quality seedlings with high survival capability. Thus the nursery needs to create seedlings with plant attributes that allow for the best chance of success once a seedling is field planted. Since the mid-twentieth century, research foresters have critically examined plant attributes that confer improved seedling survival to field site conditions. This review describes the value of commonly measured seedling quality material (i.e. shoot height, stem diameter, root mass, shoot to root ratio, drought resistance, mineral nutrient status) and performance (i.e. freezing tolerance and root growth) plant attributes defined as important in answering the question of why seedlings survive after planting. Desirable levels of these plant attributes can increase the speed with which seedlings overcome planting stress, become ‘coupled’ to the forest restoration site, thereby ensuring successful seedling establishment. Although planting seedlings with these desirable plant attributes does not guarantee high survival rates; planting seedlings with desirable plant attributes increases chances for survival after field planting.     

基于人工智能的苗木质量无损检测研究进展

我国森林面积广域，人工林面积居世界首位。为了确保质优量足的苗木进一步提升苗木造林效果，苗木质量的无损检测成为苗木质量精准快速评价的关键。文中概述人工智能理论与算法在苗木质量的形态、生理和活力指标3个方面的无损检测应用现状；针对传统检测指标单一、效率低和主观误差大的问题，指出综合应用图像采集、数字图像处理和机器学习技术的人工智能算法与理论在苗木质量评价指标检测领域具有明显优势，并从检测技术融合、提升检测算法和多源数据融合等方面进行展望，旨在为苗木质量快速精准评价提供参考。     

Initial seedling morphological characteristics and field performance of two Sudanian savanna species in relation to nursery production period and watering regimes

It has become apparent that some interventions are required to aid the regeneration of woody species in the Sudanian savanna. Direct seeding has been ineffective, thus planting high quality seedlings may be a viable alternative. In this study, we examined the stock quality of two valuable Sudanian savanna species, Acacia macrostachya and Pterocarpus erinaceus. Different nursery production periods were tested as well as the species’ field performance under well-watered and stressed conditions. The results showed that older seedlings (9-month) were morphologically distinct from younger ones (3-month), particularly in the case of P. erinaceus. Eighteen months after planting out, survival and growth of seedlings were not affected by initial seedling size; this was the result of the high root to shoot ratio of seedlings in all age groups at the time of planting. Seedling mortality as high as 30% was observed and attributed to both drought stress and other factors such as herbivory. Regression analyses revealed that initial shoot height was a poor predictor of field performance for both species, but initial root collar diameter accounted for 25% of the variation in diameter of P. erinaceus in the field. We conclude that initial seedling size does not affect survival and growth in the field provided that all sizes of seedling have a high root to shoot ratio at the time of planting. The prediction of field performance could be improved by developing a model that incorporates a wide range of root collar diameter.