Natural Variation of Leaf Thickness and Its Association to Yield Traits in indica Rice

Leaf thickness is an important morphological trait in rice. Its association to the yield potential, as of now has not been documented because of the shortage of the equipment which could conveniently measure the leaf thickness in rice. In this study, the thickness of top three leaves of 208 cultivars had been determined by a nondestructive rice leaf thickness instrument for the research of the natural variation of leaves thickness and its association to yield traits in indica rice. The results showed that the flag leaf was the thickest, and the 2nd leaf was thicker than the 3rd leaf. Analysis of variance indicated the existence of wide genetic diversity of leaf thickness among the investigated indica rice genotypes. The tight correlation among the thicknesses of the top three leaves means that the leaf thickness traits share one genetic control system. Leaf thickness had a significant positive correlation with leaf length and a positive correlation with leaf width, indicated that thicker leaf was beneficial to increasing the single leaf area. The results of correlation analysis revealed that thicker leaf should be profitable to the leaf erection, higher numbers of grains per panicle and higher grains weight per panicle. However, the significantly negative correlation between leaf thickness and number of panicles per plant counteracted the profitability from increased grains weight per panicle, so that the correlations of the thicknesses of the top three leaves to yield and biomass were positive but not significantly. It has made great progress in the genetic improvement of leaves thickness in inbred indica rice breeding in Guangdong Province, China, since the 1990s.

Preliminary Studies on Thickness of Nondestructive Rice (Oryza sativa L.) Leaf Blade

Two varieties, Yuexinzhan and Guangchao 3, were used to study leaf thickness in rice in this experiment. The thickness of the leaf blade was measured by the nondestructive leaf thickness instrument, which was modified from the thickness instrument for steel objects （John Bull, England）. The contacting area between the leaf and the probe of the instrument was 0.5 cm^2. There was no significant difference between the thickness of steel materials measured by the nondestructive rice leaf thickness instrument and the micrometer. The correlation between the thickness of the rice leaf blade measured by the nondestructive rice leaf thickness instrument and the specific leaf weight （SLW） was significant （P 〈 0.05 or P〈 0.01）. The results also showed that the rice leaf thickness was uneven and asymmetric. The thickness and SLW of flag leaf tended to increase from the base to the tip of the leaf blade. The middle part of the second and third top leaf was the thickest, but no significant difference in thickness between the basal part and the fore part was found. Drawing a line on the main vein in the top three leaves, the left part was thinner than the right part. The thickness of the lower leaves （6/0-9/0） on the main culm tended to increase with increasing positions of the leaves in the early and middle stages, but the tendency was not the same for the higher leaves （10/0 upwards）, although the higher leaves （10/0 upward） were thicker than the lower leaves （9/0 or downward）. Furthermore, different CO2 concentrations （550±30, 460 ± 30 μmol mol^-1） in the growth boxes had no effect on the thickness of rice leaf blades. It can be concluded that the measurement of rice leaf thickness using the nondestructive rice leaf thickness instrument is simple, precise, and nondestructive.

Arbuscular mycorrhizal fungi-mediated resistance to salt spray in Cinnamomum camphora seedlings enhanced by leaf functional traits

Salt spray is a natural disturbance in coastal region.Arbuscular mycorrhizal fungi(AMF)are recognized as bio-ameliorators of soil salinity in plants.However,the mechanism through which AMF protects Cinnamomum camphora against aerial salinity remains unclear.To address this knowledge gap,plants were subjected to four fungal regimes,namely sterilized fungal inoculum,Glomus tortuosum,Funneliformis mosseae,or a combination of these two fungi,and exposed to three sprayed-salt regimes(0,7,or 14 mg NaCl cm−2 d−1)in a greenhouse.Salt spray significantly decreased photosynthetic capabilities,total dry weight,and salinity tolerance of non-mycorrhizal plants.Mycorrhizal inoculation,particularly a combination of G.tortuosum and F.mosseae,evidently mitigated the detrimental effects induced by salt spray.Meanwhile,mycorrhiza-mediated protection depended on the intensity of sprayed salt and the identity of fungal taxa.Furthermore,the enhanced resistance of mycorrhizal C.camphora seedlings to aerial salinity was mainly owing to increased leaf thickness and photosynthetic capabilities.These findings imply that inoculation with combined fungi could be an optimal strategy for cultivating C.camphora plants in coastal regions.The results gained hold the potential to offer both theoretical and practical guidance for the managers of coastal ecosystems in soil restoration and conservation.

Development of a Compound Photorespiration Inhibitor and Its Application on Sweet Cherry

[Objectives]This study was conducted to investigate the effects of compound photorespiration inhibitors on related indexes of sweet cherry.[Methods]With the main sweet cherry variety‘Meizao’as a test material,relevant research work was carried out.[Results]Several compound photorespiration inhibitors had a better promotion effect on the photosynthetic capacity,yield and quality of sweet cherry variety‘Meizao’,and especially,the combination of 300 mg/L sodium bicarbonate,300 mg/L sodium bisulfite,300 mg/L 2,3-epoxypropionic acid and 1.5%tween-80 had the best effect.[Conclusions]The combined use of the three photorespiration inhibitors is better than the single use,and produces a good synergistic effect.

Leaf traits indicate survival strategies among 42 dominant plant species in a dry, sandy habitat, China

The objective of this paper was to assess the congruency of leaf traits and soil characteristics and to analyze the survival strategies of different plant functional types in response to drought and nutrient-poor environ-ments in the southeastern Ke’erqin Sandy Lands in China.Six leaf traits—leaf thickness(TH),density(DN),specific leaf area(SLA),leaf dry weight to fresh weight ratio(DW/FW),leaf N concentration(N mass),and N resorption efficiency(NRE_(mass))-of 42 plant species were investi-gated at four sites.The correlations between leaf traits and soil characteristics-organic C(OC),total N(TN),total P(TP),and soil moisture(SM)-were examined.We found that the six leaf traits across all the 42 species showed large variations and that DW/FW was negatively correlated with OC,TN,TP,and SM(P<0.05),while other leaf traits showed no significant correlations with soil characteristics.To find the dissimilarity to accommodate environment,a hierarchical agglomerative clustering analysis was made of all the species.All the species clustered into three groups except the Scutellaria baicalensis.Species of group III might be most tolerant of an arid environment,and species of group II might avoid nutrient stress in the nutrient-poor environment,while group I was somewhat intermediate.Therefore,species from the different groups may be selected for use in vegetation restoration of different sites based on soil moisture and nutrient conditions.

Leaf traits and their interrelationship of 23 plant species in southeast of Keerqin Sandy Lands,China

Six leaf traits,i.e.,fresh mass(FM),dry mass(DM),leaf dry matter content(DMC),area(AR),specific leaf area(SLA)and thickness(TH)from 23 plant species in the southeastern Keerqin Sandy Lands,China were measured.The results show that leaf traits of herbs were more diversified than those of shrubs and trees and aver-age SLA tended towards a decreasing trend from herbs to shrubs to trees.On the contrary,DMC and DM show an upward trend from herbs to shrubs to trees.No apparent difference was found in TH.Except for DM and TH,there were significant variations in SLA and DMC among three different growth forms.Moreover,a significant correlation was found between SLA and DMC.It is concluded that SLA and DMC could be used to predict species position along a resource use gradient.