Responses of Caryopsis Germination, Seedling Emergence, and Development to Sand Water Content of Agropyron cristatum （L.） Gaertn. and Bromus inermis Leyss.

Responses of caryopsis germination, seedling emergence, and development of Agropyron cristatum （L.） Gaertn. （Gramineae） and Bromus inermis Leyss. （Gramineae）, two dominant perennial grasses in the Otindag Sandland of China, to different sand water content （SWC; 1%, 2%, 3%, 4%, 6%, 8%, 12%, 16%, and 20%） were studied comparatively. The results showed that the germination responses of the two grasses to SWC were similar （i.e. caryopses could not germinate when the SWC was below 3%; at SWC ranging from 3% to 12%, the higher the SWC, the higher the germination percentage; and at a SWC of 12%-20%, germination reached similarly high percentages）. At a sand burial depth of 0.5 cm, the threshold of SWC for seedling emergence was 6% forA. cristatum and 8% forB. inermis; at 12%-20% SWC, the seedling emergence of both species reached similarly high percentages. The seedling growth responses of these two species to SWC gradients were different. For A. cristatum, the biomass of seedlings increased with SWC from 6% to 12%, and decreased with SWC from 12% to 20%. For B. inermis, the biomass of seedlings always increased with SWC from 8% to 20%. The results also showed that the seedlings of both species allocated more biomass to the roots with decreases in SWC. The SWC changes from April to October in natural microhabitats of both species suggested that the SWC may play an important role in caryopsis germination, seedling emergence, and the growth characteristics of the two grasses. The responses of caryopsis germination, seedling emergence, and the growth characteristics of these two species to SWC may determine their distribution pattems in the Otindag Sandland.

不同处理对朝鲜白头翁种子萌发的影响

以朝鲜白头翁种子为材料,测定其基本特征和吸水特性,研究GA3、PEG6000浸种和超声处理对其种子萌发的影响。结果表明,朝鲜白头翁种子具有快速吸水的生物学特性,入水后1 h的吸水量可达最大吸水量的61.09%;适宜的GA3、PEG6000浸种以及超声处理均可以显著提高朝鲜白头翁种子发芽率和出苗率,100 mg.L-1GA3浸种12 h、10%~30%PEG6000浸种12 h和40℃条件下80 W超声波处理20 min,3种前处理萌发出苗效果最好,其出苗率可分别达到48.33%、52.00%和55.67%。赤霉素GA3操作简单易行,成本低,适合生产采用。

苍耳种子萌发和出苗特性的研究

通过发芽试验研究了温度、p H、光、N、P、K、播深、种子部位等因素对苍耳种子萌发出苗的影响。结果表明 ,苍耳种子的最适萌发温度在 15～ 2 5℃。苍耳为明发种子 ,可通过控制光照时间来改变其萌发率 ;其对 p H具有广泛的适应性 ,在p H为 2～ 10范围内均可萌发 ;0 .10 %～ 0 .18%范围内的含钾量 ,0 .0 0 6 %～ 0 .0 18%范围内的含磷量 ,0 .0 2 %～ 0 .18%范围内的含氮量均可以明显地增加苍耳种子的萌发速率。苍耳种子的最适播深为 0～ 4 cm 。

燕山地区不同居群白头翁种子萌发的初步评价

以燕山地区6个不同居群白头翁果实和种子为试验材料,对果实形态、种子发芽与幼苗特性进行观测与分析,并通过隶属函数法综合排序。结果表明,青龙都山居群白头翁果实长度、宽度和花柱长度最大,滦州华山峰居群的果实千粒质量、发芽率、出苗率、子叶长度、主根长度、侧根数和初生叶长度最大,蓟州于各庄居群的胚根长度、下胚轴长度和初生叶宽度最大,抚宁天马山居群的皿播苗长和子叶宽度最大。白头翁的子叶宽度、初生叶长度和发芽率是影响出苗率的关键因素,花柱长度是影响果实的长度和宽度的关键因素。以发芽率、胚根长度、出苗率和主根长度为指标,通过隶属函数法进行综合排序,滦州华山峰居群白头翁最好。