石灰性紫色土壤pH及矫治措施对甜橙叶片过氧化物酶和过氧化氢酶的影响

枳壳、红桔和香橙砧木的伏令夏橙叶片过氧化物酶和过氧化氢酶活性与紫色土壤pH 均呈极显著幂函数负相关。土壤pH 不但影响过氧化物酶活性,也引起过氧化物酶同工酶谱带数和活性的变化。三种砧木中,以香橙最耐碱,枳壳最不耐碱,砧木既影响着吸收和向叶片输送的总铁量,也可能影响铁元素的有效性。本试验所采用的四种矫治措施,均不同程度地提高了叶片中这两种酶的活性,表明确实具有明显的生理作用。     

枳砧甜橙黄化问题的研究

枳砧嫁接各种柑桔类品种,只有少酸类甜橙发生黄化。不同株系枳的单株嫁接甜橙,黄化程度有明显差异,用茎尖脱毒的暗柳橙接穗嫁接成苗后出现的黄化率反而高于用黄化的改良橙接穗。 在防虫网室中用实生暗柳橙接穗嫁接小叶大花系枳出现7.4％的黄化株和59.2％轻度黄化株,在这些黄化株上嫁接腊斯克枳橙不表现碎叶病症状,因而认为枳砧甜橙黄化系嫁接不亲和引起,与碎叶病毒无关。     

“三江并流区”不同类型土壤腐殖质特性的研究*

 为研究各类型土壤的肥力差异,初步分析了紫色土、黄棕壤、高山草甸土、石灰岩土、棕色针叶林土、棕壤、暗棕壤、红壤这8种典型土壤的腐殖质组成和性质。结果表明：仅红壤、黄棕壤的腐殖质含量属中等含量,其余6种均属高含量。腐殖质组成中,均以胡敏素占绝大多数,除暗棕壤和棕色针叶林土外,各土样中富里酸的有机碳的相对数量均大于胡敏酸的有机碳的相对数量。胡敏素含量与腐殖质、有机碳含量呈极显著相关(P＜001)。8种典型土样的腐殖化程度由高到低依次为:棕色针叶林土＞暗棕壤＞棕壤＞紫色土＞石灰岩土＞黄棕壤＞高山草甸土＞红壤。各土样胡敏酸的复杂程度和化学稳定性序列为棕壤＞暗棕壤＞黄棕壤＞紫色土＞红壤＞棕色针叶林土＞高山草甸土＞石灰岩土。各土样中富里酸的缩合度、芳香度和化学稳定性由高到低依次为:石灰岩土＞高山草甸土＞黄棕壤＞紫色土＞棕色针叶林土＞暗棕壤＞棕壤＞红壤。     

不同砧木对黄果柑光合特性、光合作用关键酶及其基因表达的影响

为了从光合生理方面了解砧木对黄果柑的影响,以枳壳、红橘和香橙为砧木,黄果柑实生苗为对照,在果实成熟期测定其净光合速率（Pn）、蒸腾速率（Tr）、胞间CO2浓度（Ci）、气孔导度（Gs）等日变化参数和光合响应曲线,以及核酮糖1,5 二磷酸羧化酶/加氧酶（Rubisco）含量、Rubisco活化酶（RCA）含量以及 Rubisco基因 （rbcS和rbcL）及其活化酶基因 （rca）表达的影响。结果表明：不同砧木嫁接的黄果柑叶片净光合速率日变化曲线均呈双峰型,存在光合午休,3种嫁接树的净光合速率均大于实生苗;其蒸腾速率的日变化均呈单峰型,水分利用效率的日变化均为双峰型。此外,香橙嫁接的黄果柑叶片有较高的净光合速率、Rubisco含量和RCA含量及较强的rbc和rca基因表达。综合比较分析,香橙砧适宜作为黄果柑的砧木进行推广。     

不同砧木锦橙叶片过氧化物酶活性与植株生长结果的关系

 不同砧木锦橙叶片过氧化物酶(POX)活性存在着差异,半矮化砧上锦橙叶片POX活性显着高于乔化砧,叶片POX活性与树高、干粗、节长、树冠体积等生长势指标呈负相关,与叶片质量、光合强度及果实产量呈正相关.因此,可把叶片POX活性作为砧木对嫁接丰产品种性及矮化性早期预测的辅助生化指标.     

石灰性紫色土桃树黄化病的诊断

采用形态诊断、土壤植物化学分析和酶学诊断法对成都市龙泉区石双性紫色土桃黄化病进行了诊断。发现桃黄化病系典型的缺铁症，发病土壤ＰＨ较高，有效铁含量低，叶片全铁、活性铁均低于正常植株，黄化叶片的过氧化氢酶活性极显著降低。故诊断将石灰性紫色土桃黄化病为缺铁所致。     

外加碳氮对不同有机碳土壤N2O和CO2排放的影响

以两种有机碳含量不同的土壤为对象,采用室内培养试验方法,研究了外加可溶性碳氮对黄棕壤(高有机碳含量)和紫色土(低有机碳含量)N₂O、CO₂排放的影响。试验设置五种处理分别为:对照(CK),低氮(LN),高氮(HN),低氮配施碳(LNC)和高氮配施碳(HNC).结果表明,土壤有机碳含量较高的黄棕壤各处理N₂O与CO₂排放均高于紫色土。与对照相比,单施氮肥显着促进了两种土壤N₂O排放,紫色土HN处理N₂O排放最高,而黄棕壤LN处理最高;与单施氮肥相比,LNC和HNC处理均显着降低了紫色土N₂O排放,而黄棕壤仅LNC处理N₂O排放显着降低。外源碳的输入显着提高了两种土壤CO₂排放,但单施氮肥对CO₂排放影响不明显。黄棕壤N₂O排放通量与CO₂排放通量呈极显着正相关,而紫色土N₂O排放通量与CO₂排放通量没有相关关系。上述结果说明,外加可溶性碳氮源对土壤呼吸及硝化-反硝化强度有一定的激发效应。     

施用生物炭对云南烟区典型土壤养分淋失的影响

土壤养分尤其是氮、钾的淋失是制约云南烟叶生产可持续发展的重要因素之一。近些年来的一些研究表明,生物炭在减少土壤养分淋失方面有着很好的应用效果。然而,关于生物炭在云南植烟土壤上的应用效果研究报道较少。本文基于土柱淋洗模拟试验,研究了添加生物炭对南方紫色土、赤红壤和黄棕壤硝态氮、磷、钾养分淋失的影响,以期为生物炭的合理广泛应用提供理论依据。研究结果显示,添加生物炭后,紫色土、赤红壤和黄棕壤的硝态氮淋洗总量分别减少16%、14%和22%;紫色土、赤红壤的磷素淋洗总量分别减少41%和32%,黄棕壤磷素淋洗总量变化不明显;紫色土和黄棕壤的钾素淋洗总量分别增加19%和23%,赤红壤的钾素淋洗总量变化不明显。研究表明,施用生物炭是控制云南植烟土壤氮磷淋失的有效措施。     

The effects of rootstocks on performances of three late-ripening navel orange varieties

Selection of rootstock is very important for citrus production. Besides its major role on resistance, the rootstock also can affect fruit production and quality. Currently, the main concerns on selection of rootstock for citrus production are compatibility and resistance, due to less information on the impacts of rootstock to the performance of scion varieties. This study aims to provide information on performances of navel orange varieties on different rootstocks. Three late-ripening navel orange varieties(Citrus sinensis var. Powell, Chislett and Banfield) grafted on seven rootstocks(Swingle citrumelo(C. paradisi× P. trifoliata), Carrizo citrange(C. sinensis×P. trifoliata), X639(C. reticulata×P. trifoliata), MXT(C. sinensis×P. trifoliata), Hongju(C. reticulata), Ziyang Xiangcheng(C. junos) and trifoliate orange(P. trifoliata)) were used as plant materials for comprehensive comparison of the performances on tree growth, fruit yield and quality in 21 scion–stock combinations. Investigation was carried out in these combinations in field nine years after planting. Vigorous growth of all the three late-ripening navel orange varieties was observed on Carrizo citrange with the largest canopy volume at 33.34 m3 and the highest yield at 29.43 kg per tree, but a low yield efficiency at 2.87 kg m–3. On the contrary, those on trifoliate orange had the smallest canopy volume at 10.79 m3 and the lowest fruit yield at 12.51 kg per tree, but the highest yield efficiency at 3.95 kg m–3. Rootstocks did not show significant effects on fruit size, fruit shape index, peel thickness and the edible rate of the fruits, but fruit quality was significantly affected by the rootstocks. Fruits from the trees grafted on trifoliate orange presented the best quality with significantly higher total soluble solids(TSS) content than those on Ziyang Xiangcheng and Hongju, and also the highest ratio of TSS/titratable acidity(TA). The TA content was observed from the fruits on X639 at 0.59 g 100 mL–1. Vitamin C(Vc) content of fruits on Hongju was the highest at 49.25 mg 100 mL–1. Growth vigor of the trees was positively correlated with fruit yield at an extremely significant level. The canopy volume was negatively correlated with yield efficiency, but positively correlated with compatibility index. Results of this study indicated that the rootstock has great impacts on the growth vigor of the tree, yield efficiency and quality of the fruit. In order to achieve good quality and yield efficiency for navel orange production, less growth vigor rootstock such as trifoliate orange is highly recommended.     

苹果砧木脱落酸与树木生长规律的研究

用气象色谱法分析了苹果矮化砧木和乔化砧木5月10日～11月10日叶片内源脱落酸(ABA)的含量水平。结果表明:(1)矮化和乔化砧木叶片内ABA含量以相似的规律变化着,其内在变化影响树体新梢生长、幼芽发育及落叶等生长环节,(2)矮化砧木的ABA含量水平始终高于乔化砧木,通过对M,S和SH系的相关分析,表明树体叶片的ABA含量水平与树体高度、树干周长及新梢长度均呈显著负相关。