梨树在自然干旱条件下叶片解剖学特征

比较测定了水、旱地梨树的叶片解剖构造、气孔分布密度与相对开张度、气孔传导率、蒸腾速率以及光合速率。结果表明 ,梨树在自然干旱条件下 ,叶片厚度极显著地变薄 ,栅栏组织厚度、海绵组织厚度和表皮厚度也均显著或极显著地变薄。但是 ,栅叶比和栅海比则无显著变化。在自然干旱条件下 ,梨树叶片气孔密度增大 ,而气孔相对开张度却变小。气孔传导率、蒸腾速率和光合速率均无显著变化  

用隶属函数值法评价10个蓖麻品种抗旱性

以10个蓖麻盆栽幼苗为试材,采用自然干旱胁迫方法,研究了自然干旱胁迫对其幼苗生长7个生理生化指标的影响,并用模糊隶属函数值法对其抗干旱能力进行综合评价。结果表明,10个蓖麻品种的抗旱性排序为:Z5>F7>ZhB7>JX2>T202>Zh3>HZT>A007>T5>JB2,同时表明,抗旱性是一个综合指标,不应由单一指标决定。  

干旱胁迫对4种灌木生理生化特性的影响

采用自然干旱方式，对美丽胡枝子Lespedeza formosa，马棘Indigofera pseudotinctoria，伞房决明Cassiacorymbosa和紫穗槐Amorpha fruticosa等4种灌木进行干旱胁迫条件下的抗氧化酶（超氧化物歧化酶SOD和过氧化物酶POD）活性、脯氨酸（Pro）质量分数和丙二醛（MDA）质量摩尔浓度的影响试验。结果表明：在土壤相对含水量逐渐下降的过程中，美丽胡枝子和马棘的SOD活性初期变化较小，后期迅速上升．复水后有所下降。伞房决明和紫穗槐则是初期上升至最大值后下降，复水后小幅上升：POD活性总体上均呈先升后降复水后上升的变化趋势，但不同植物的POD活性大小存在一定差异：MDA质量摩尔浓度在胁迫初期下降，随胁迫程度的加剧，逐渐上升，复水后又下降；Pro质量分数在胁迫期间上升、复水后下降．美丽胡枝子变化幅度最大，伞房决明变幅最小。干旱胁迫引起了美丽胡枝子等4种灌木植物体内生理生化物质含量的变化．但不同植物的变化趋势不尽相同，受植物体内物质的综合调控，其抗旱机制存在一定差异．相比之下伞房决明的抗旱能力较强。图5参10  

Photosynthetic Characteristics of Clerodendrum trichotomum Thumb.Responses to Drought,Salt and Water-logging Stresses

In order to reveal the photosynthetic characteristics of C.trichotomum responses to drought,salt and water-logging stresses,one-year-old potted seedlings were taken as materials,and the several stresses including natural drought,submergence stress,water-logging and different salt treatments (0.2％,0.4％,0.6％ and 0.8％ NaCl) were carried out on August 15,2012.The morphological and photosynthetic characteristics were observed and determined.The results showed that adverse enviromental stress had a significant effect on the morphological changes and photosynthetic characteristics of C.trichotomum.On the 14th day after natural drought,the leaves wilted and could not recovery at night,and 60％ of the seedlings could recover after re-watering.From the 7th day to the 10th day after submergence stress treatment,the 2nd and the 3rd leaves at the base of 60％ seedling turned yellow and the lenticels were observed.At the early stage of water-logging stress,white lenticels appeared at the base of seedlings,and the leaves wilted,chlorina and fallen off on the 8th day.A large number of leaves fallen off under 0.6％ NaCl or more salt stress,and even the whole plant died.The chlorophyll content,net photosynthetic rate (Pn) and transpiration rate (Tr) decreased gradually with the stress process,such as 8 days after natural drought,less than 0.4％ salt stress and water-logging stress,but the changes were not significant compared with those of the control.With the increase of the stress intensity and the prolonged time,the changes of photosynthetic index were significant.All the results indicated that C.trichotomum had a certain degree of tolerance to drought,water and salt,but it was not suitable for living in water-logging condition for a long time.  

土壤自然干旱及复水对通关藤抗旱能力的影响

以通关藤为材料,设计4个实验处理组,分析通关藤在干旱胁迫及复水后抗旱生理指标的变化,为通关藤的仿野生栽培提供理论指导.结果表明,脯氨酸及可溶性糖含量随着胁迫程度的加剧,呈“先升高后降低”的变化趋势,2个指标均在第8天时达到最大值,各胁迫处理的含量均显著高于对照;MDA含量呈“先升高后降低再升高”的趋势,胁迫第8～ 12天时MDA含量显著低于对照;SOD和POD在整个胁迫期内活性均显著高于对照,复水后其活性有所降低,但仍高于对照.上述变化结果表明,干旱胁迫8～12d达到通关藤抗旱高峰,随后抗旱能力下降,胁迫解除后自身修复能力较强.