Effects of uniconazole or gibberellic acid application on the lignin metabolism in relation to lodging resistance of culm in common buckwheat (Fagopyrum esculentum M.)

Lignin plays an important role in increasing the mechanical intensity of culm and improving lodging resistance of culm. In this study, three common buckwheat, Youqiao2 (lodging‐tolerant cultivar; YQ2), Ningqiao1 (middle lodging‐tolerant cultivar; NQ1) and Ukraine daliqiao (lodging‐susceptible cultivar; UD), were used to investigate the effects of spraying exogenous hormones uniconazole (S‐3307) or gibberellic acid (GA3) on lignin metabolism and its relation to lodging resistance in the three common buckwheat cultivars. Results showed that application of S‐3307 significantly increased lignin content and its related enzymes activities of phenylalanine ammonia‐lyase (PAL), 4‐hydroxy cinnamoyl CoA ligase (4CL), cinnamyl alcohol dehydrogenase (CAD) and peroxidase (POD). The major genes involved in lignin synthesis, PAL, CCR (cinnamyl CoA reductase), C4H (cinnamate4‐hydroxylase), 4CL and CCoAOMT (caffeoyl CoA O‐methyltransferase), were all upregulated expression, and COMT (catechol‐O‐methyltransferase) was downregulated. What is more, application of S‐3307 significantly improved the resistance of common buckwheat stem to lodging and increased yield. Whereas, spraying with GA3 caused opposite effect on those characteristics. These results suggested that application of exogenous S‐3307 or GA3 significantly changed the risk of lodging occurred by regulating the lignin metabolism in culms of common buckwheat.     

芷江野生南方红豆杉资源现状及保护对策

简述了野生南方红豆杉在芷江侗族自治县的分布现状、生境条件，分析了珍稀濒危的原因，探讨了野生南方红豆杉的保护对策。     

华北落叶松胚性组织超低温保存技术研究

  目的  超低温保存是植物优良种质长期保存的重要方法。本文为探究梯度预处理对超低温保存存活率的影响，以期有效保存华北落叶松胚性组织的发育潜能。  方法  本研究以华北落叶松胚性组织为材料，对超低温冷冻保存程序中预培养、冷冻处理方式、解冻方式和恢复培养等关键环节开展研究。预培养和冷冻保护共设计成4种处理，以不经过预培养和冷冻保护直接冷冻保存为对照，每个处理重复3次。  结果  结果表明:处理组合1、2、3之间虽无显著差异，但结合冷冻保护剂二甲基亚砜（ DMSO）对细胞具有一定毒害作用，高浓度的DMSO会影响后续胚性组织的恢复甚至造成细胞死亡，因此选出效果较好的超低温保存方法为: 0.2、0.4 mol/L山梨醇液体梯度预处理与0.4 mol/L山梨醇 + 5%DMSO为冷冻保护剂进行冷冻保护，最佳解冻方式为37 ℃水浴，解冻后的胚性愈伤组织细胞活性最高达78%；超低温保存后的胚性组织与正常增殖的胚性组织在外观及显微结构上无明显差异，且低温保存后的愈伤组织仍保持分化形成体细胞胚的能力。  结论  研究结果为华北落叶松乃至其他针叶树胚性组织的超低温保存提供了参考。      

樟子松人工林摘芽修枝试验初报

樟子松造林后第4年进行摘芽试验,结果表明,摘芽与不摘芽的高生长和胸径生长存在明显差异,摘芽处理的高生长较不摘芽处理高出13.9%,胸径生长高出9.49%;摘芽处理树干无节高度平均为5.0 m,无节处直径与根径相差2.7 cm,而未摘芽的直径与根径相差5.4 cm,树干圆满度显著提高,经济效益明显。     

蓝萼香茶菜子叶组织脱分化及再生培养研究

以蓝萼香茶菜的子叶为外植体,研究诱导愈伤组织不同激素的最佳浓度,建立蓝萼香茶菜的快速繁殖体系。结果表明:蓝萼香茶菜子叶在2,4-D 0.8 mg/L、KT 1.4 mg/L6、-BA 1.5mg/L时最早出现愈伤组织,且愈伤组织长势最好。     

The flexural properties of young Pinus elliottii x Pinus caribaea var. hondurensis timber from the Southern Cape and their prediction from acoustic measurements

The objectives of this study were to determine the bending strength and stiffness properties of young Pinus elliottii x P. caribaea var. hondurensis timber from the Southern Cape, South Africa, and to evaluate the predictability of these properties from acoustic measurements on standing trees, logs and their sawn boards. The timber has good bending strength (MOR) properties but the mean stiffness (MOE_stat) was significantly lower than that required for structural-grade timber. The mean MOE_stat was also about 30% lower than a P. radiata control sample. The MOE_stat of sawn boards could be predicted from acoustic stress wave measurements on standing trees with a correlation (r) of 0.48 and from acoustic resonance frequency measurements on sawn boards with a correlation of 0.85. The MOR of sawn boards was not significantly correlated with acoustic stress wave measurements on standing trees and only moderately correlated with acoustic resonance frequency measurements on sawn boards (r = 0.45).     

天山中部林区疏林地分类及改造措施的初步研究

以天山中部林区人为不合理采伐形成的天山云杉疏林为研究对象，根据调查收集的４５块疏林地典型样地资料，从分析天山云杉疏林地的立地条件和林分特征入手，采用主分量分析，聚类分析的方法，将天山中部林区天山云杉疏林地划分为四种类型，并按因地，因地制宜的原则，提出了相应的改造利用措施。     

四川凉山州光叶紫花苕良种选育及推广研究

通过对凉山光叶紫花苕良种选育及应用研究，系统分析了该草种在不同生态条件下（海拔１５００～３２００ｍ）的生物学和生态学特性。主要经济性状是：分枝期全草干物质中粗蛋白含量为３０．６９％，粗脂肪８．７０％，粗纤维２２．８０％，无氮浸出物为２８．０３％，粗灰分８．７２％，钙１．４８％，磷０．２３％，还含有１７种必需氨基酸。平均鲜草产量４５０００～７５０００ｋｇ／ｈｍ２，种子产量６００～１２００ｋｇ／ｈｍ２。１９９６～１９９８年全州种植面积达８．５万ｈｍ２，鲜草总产２６．２６８亿ｋｇ，产值２．６２６８亿元，推动了全州畜牧业生产的发展。     

南方红豆杉林下幼苗空间分布型的研究

采用聚集度（C，I，Iδ．X和CA等）及IwaoX－回归和Taylor回归分析方法研究了南方红豆杉林下幼苗的分布型．研究结果表明，南方红豆杉在林下的分布呈聚集分布型（α＞0，β＝1）。对IwaoX－X的回归方程参数α和β进行随机偏离度的检验，结果α值和0差异极显著，β值与1差异不显著。     

中国北方生态型笋形茎用芥‘鲁笋芥1号’

原产四川的芥菜种笋子芥变种引种到北方后因先期抽薹严重，不能形成产品器官，“鲁笋芥1号”是根据植物对光周期反应原理，新育成的北方生态型笋形茎用芥新品种，早熟、高产、质优、抗病，可秋春两作，笋茎产量30－40t/hm^2，可食叶片15－20t/hm^2。